radiation safety in perioperative practice · the long-term health effects of ionizing radiation...

RADIATION SAFETYIN PERIOPERATIVE PRACTICE

1970

1970RADIATION SAFETY IN PERIOPERATIVE PRACTICE

STUDY GUIDE

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Reprinted with permission from The Association of periOperative Registered Nurses, Inc.

Copyright 2014 “RADIATION SAFETY IN

PERIOPERATIVE PRACTICE.”

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PURPOSE/GOAL .............................................................................................................................4

OBJECTIVES....................................................................................................................................4

INTRODUCTION.............................................................................................................................5

IONIZING RADIATION ..................................................................................................................5

ADVERSE EFFECTS OF IONIZING RADIATION .......................................................................5

FUNDAMENTAL CONCEPTS AND PRACTICES........................................................................7

RADIATION SOURCES IN PERIOPERATIVE PRACTICE .........................................................9

DOSE LIMITS AND REGULATIONS ..........................................................................................13

DOSIMETRY ..................................................................................................................................13

CONCLUSIONS AND RESOURCES............................................................................................17

GLOSSARY ....................................................................................................................................18

POST-TEST.....................................................................................................................................23

POST-TEST ANSWERS .................................................................................................................26

RADIATION SAFETY IN PERIOPERATIVE PRACTICE

Radiation Safety in Perioperative Practice

TABLE OF CONTENTS

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PURPOSE/GOAL

The purpose of this study guide and accompanying video is to educate perioperative personnel on the clinical applications,

risks, and safety practices for the use of ionizing radiation in perioperative practice.

OBJECTIVES

After viewing the video and completing the study guide, the participant will be able to

• define ionizing radiation;

• summarize the acute and long-term adverse effects of ionizing radiation exposure;

• list the types, sources, and applications of ionizing radiation in perioperative practice;

• explain the linear-no-threshold model and the concept of ALARA;

• describe how to use the principles of time, distance, and shielding to minimize radiation exposure for personnel and

patients;

• define federal dose limits and describe state regulations on occupational and public radiation exposure; and

• understand the proper use of dosimetry to measure radiation exposure.

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INTRODUCTION

Radiographic modalities that use ionizing radiation play an

essential diagnostic and therapeutic role in numerous areas of

perioperative practice.1 For both patients and health care

personnel, however, ionizing radiation exposure can increase

the risks of acute and long-term health effects, such as skin

injury and cancer. By implementing proper radiation safety

practices, perioperative nurses and other team members can

substantially decrease the risks of ionizing radiation exposure

for patients and health care workers.

The expanding use of ionizing radiation during invasive

procedures underscores the need for radiation safety education

and training for perioperative nurses. This study guide and the

accompanying video review the definitions, clinical uses and

risks of ionizing radiation, federal and state regulations and

radiation dose limits, and essential concepts and practices to

minimize radiation exposure for patients and personnel.

IONIZING RADIATION

Radiation is energy emitted by matter in the form of high-

speed particles or rays.2 When radiation is of high enough

frequency, it has sufficient energy to remove tightly bound

electrons from atoms. This process is called ionization

because it creates ions, and these high-energy forms of

radiation are called ionizing radiation. Ionizing radiation (ie,

radioactivity) includes gamma rays, x-rays, alpha particles,

beta particles, neutrons, and positrons. Non-ionizing radiation,

which does not have sufficient energy to displace electrons

from atoms, includes radio waves, microwaves, visible light,

heat, and radar. This study guide and the accompanying video

focus on ionizing radiation.

Ionizing radiation penetrates and ionizes atoms and molecules

in living tissue, which is the basis of its applications in

diagnostic and interventional radiology, nuclear medicine, and

radiotherapy. Two sources of ionizing radiation used in

perioperative and other clinical practice settings are radiation-

producing devices,

such as x-ray and

fluoroscopy machines,

and radionuclides,

which are atoms with

unstable nuclei that

emit radioactive

particles as they

decay.1 The most

common forms of

ionizing radiation

used for medical purposes are gamma radiation, x-rays, and

positrons.

Gamma radiation

is electromagnetic

radiation emitted

from the nuclei of

radioactive atoms.1

Gamma radiation

can deeply penetrate

living tissue and is

used in nuclear

medicine. However,

gamma radiation exposure can also occur during the use of

Iodine-131 (I-131), an isotope that emits both gamma and beta

radiation. I-131 causes cell death when it undergoes beta

decay and is used during inpatient and outpatient thyroid

procedures, such as in the treatment of hyperthyroidism and

thyroid cancer.1,3

X-rays share many characteristics with gamma radiation, but

are emitted from the electronic shell instead of the nucleus of

atoms.4 X-ray photons used in medicine are created when

electrons are accelerated to a high speed inside a metal tube

before colliding with a metal target.1 X-rays are primarily used

in diagnostic radiology, computed tomography (CT),

fluoroscopy, and during x-ray therapy for cancer.

Positrons are positively charged particles emitted from the

nuclei of some radionuclides.1 When positrons and electrons

interact, both are converted to photons. Positrons are used in

positron emission tomography (PET) scans to evaluate

metabolic activity. Because malignancies have higher

metabolic activity than normal human tissue, PET scans are a

sensitive and noninvasive method for detecting conditions

such as malignant pulmonary nodules, breast tumors, and liver

metastases.5,6

ADVERSE EFFECTS OF IONIZING RADIATION

Ionizing radiation has numerous potential diagnostic and

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therapeutic benefits. However, exposure to ionizing radiation

can be hazardous for patients as well as radiologists,

radiologic technologists, surgeons, perioperative nurses, and

other personnel who work with radiologic modalities.1,7 It is

essential to understand that ionizing radiation poses risks for

everyone, not just people who are pregnant or of reproductive

age.7 At sufficient doses, all types of ionizing radiation can

cause acute damage to tissue. In addition, ionizing radiation

exposure directly increases the risk of serious long-term health

outcomes, most notably cancer.

While ionizing radiation can adversely affect all living cells,

some types of cells are more sensitive to radiation exposure

than others. When cells are dividing, DNA damage can cause

the death or mutation of daughter cells.8 Cells that are highly

mitotic (divide rapidly) or undifferentiated are most sensitive

to the deleterious effects of ionizing radiation exposure. Thus,

the most radiosensitive cells include those of the

hematopoiesis system, gonads, and developing embryo, while

the least radiosensitive include muscle and nerve cells.8-10

Ionizing radiation causes both stochastic and deterministic

effects on human tissue.1,11 Deterministic effects occur acutely

after a threshold radiation dose is reached, and increase in both

incidence and severity as dose increases past threshold.

Examples of deterministic effects include acute cutaneous

radiation injury, sterility, cataracts, acute radiation syndrome,

and teratogenesis or fetal death. These adverse outcomes result

from cellular death, which is most likely to occur after

relatively high radiation doses delivered over a short time

period.1

Because patients undergo direct irradiation during radiologic

procedures, they are at higher risk for deterministic health

effects than health care workers. However, relatively low

threshold doses of ionizing radiation can cause progressive

cataracts.12,13 One study reported that cataracts can occur if

the lens of the eye is exposed to ionizing radiation doses of

100 centigray or less.13 Therefore, personnel who work with

ionizing radiation, such as radiologic technologists,

radiologists, and perioperative team members, are at risk for

radiation-induced cataracts unless proper eye protection is

consistently used. In one study of health care workers in

Serbia, the occupational incidence of cataract was 64% for

radiologic technologists, 16% for radiologists, and 4% for

nurses.13

The primary perioperative nursing diagnosis relevant to this

study guide is impaired skin integrity caused by gamma

radiation exposure.7 Acute cutaneous radiation injuries

typically affect the epidermis during early stages and the

dermis at later stages.14 Signs and symptoms include skin

erythema, edema, blistering, dry and moist desquamation,

ulceration, hair loss or loss of the nails at the irradiated site,

itching, and localized changes in sensation. Complications can

be serious and include pain, bleeding, fluid loss, and infection.

Acute cutaneous radiation injuries can occur in patients who

have undergone fluoroscopically guided interventional

procedures, such as cerebral aneurysm embolization. Minimal

threshold radiation doses associated with acute cutaneous

radiation injury have been estimated at 3.5 to 5 gray (Gy).14

However, in a prospective study of 702 fluoroscopically

guided endovascular neurosurgery cases, almost 40% of

patients who received skin doses exceeding 2 Gy reported

subsequent subacute skin changes or hair loss, and 30% of

these patients reported permanent hair loss.15 Acute cutaneous

radiation effects also can occur in patients who undergo

radiation therapy for cancer. The concurrent use of

chemotherapy further increases the risk of radiation-induced

skin injury in cancer patients.16

In contrast to deterministic effects, stochastic health effects

occur by chance.1 An example of a stochastic health effect is

cancer, which is the most serious long-term adverse outcome

from radiation exposure. Almost 41% of people born in the

United States will be diagnosed with some type of cancer in

their lifetimes, according to population estimates by the

National Cancer Institute.17 Exposure to ionizing radiation

further increases this risk, as indicated by long-term follow-

up studies of survivors of atomic bomb blasts.18,19 Although

radiation doses used in clinical practice are of course much

lower, repeated exposure to medical doses of ionizing

radiation increases the risk of cancer.20-24 For example,

ependymomas have been reported in patients who underwent

gamma knife surgery, a minimally invasive procedure in

which gamma radiation is used to treat neurological disorders

such as spinal meningiomas.23 Furthermore, repeated

exposure to ionizing radiation from CT scans has been

associated with an increased risk of solid organ tumors.24 In

one study of endovascular repair patients, patients who

underwent eight CT scans for postoperative surveillance over

four years had a significantly increased risk of new solid organ

tumors compared to patients who underwent CT once in either

three or five years.24

The long-term health effects of ionizing radiation exposure in

health care personnel have been challenging to study because

individual dose data often are lacking.25

Some researchers have proposed that exposure to ionizing

radiation can increase the risk of hereditary defects such as

trisomy 21 (Down syndrome).26 For example, a cluster of

trisomy 21 cases was reported in Berlin nine months after the

Chernobyl reactor accident.27 Reports of such clusters have

contributed to the misconception that if a woman is exposed

to ionizing radiation, her germ cells will be affected and her

offspring will be more likely to have birth defects or cancer.1

To date, epidemiologic studies of humans exposed to ionizing

radiation have not confirmed this hypothesis, although this

effect has been observed in studies of animals.1,28

In contrast, human prenatal exposure to ionizing radiation has

definitely been linked to adverse effects in the fetus or

developing embryo.1,28,29 Ionizing radiation poses greater risks

during gestation because embryonic and fetal cells are rapidly

dividing.1 The effects of ionizing radiation on an embryo or

fetus vary based on the stage of gestation and the radiation

dose.1 During approximately the first 10 days after conception

and before implantation, ionizing radiation exposure is

thought to have an all-or-nothing effect on the embryo,

meaning that either development is unaffected or spontaneous

abortion occurs.29 Ionizing radiation exposure later during

gestation has been associated with increased rates of

teratogenic effects in humans (eg, mental retardation,

intrauterine growth retardation, childhood leukemia).1,28

Ionizing radiation can cause adverse health effects through

both direct beam and scatter exposure.5 Direct beam

exposure occurs when anatomical structures are directly in the

radiation beam. This risk is most relevant for patients, but can

affect health care workers who must manually position

patients during radiographic procedures.7 Scatter occurs when

radiation strikes and then deflects away from the body or from

surrounding surfaces, such as walls or procedure tables. It is

important to keep in mind that scatter can occur in any

direction and is the primary occupational source of ionizing

radiation exposure in health care facilities.7 Practices for

minimizing the risks of adverse effects of direct beam and

scatter radiation exposure will be discussed in detail later in

this study guide.

FUNDAMENTAL CONCEPTS AND PRACTICES

This section of the study guide reviews concepts and general

practices that are fundamental to radiation safety. First, studies

of the stochastic effects of ionizing radiation exposure in

humans and animals underlie an important hypothesis call the

linear-no-threshold model.30 This model proposes that

stochastic effects can result from any dose of ionizing

radiation and that the probability of occurrence increases

linearly with radiation dose. The linear-no-threshold model is

based on the assumption that a radiation dose of any size has

the potential to cause DNA double strand breaks (that is, sever

both strands of DNA), which can result in cell death or

genomic rearrangements.29 Thus, the linear-no-threshold

model asserts that the risk of stochastic health effects is very

low when ionizing radiation doses are low, but that risk

increases with dose, and that there is no minimum safe dose

of exposure.

The linear-no-threshold model guides radiation safety

practices for both patients and health care workers. For

patients, the model is used to weigh the decision to use

ionizing radiation for clinical benefit against the patient’s

long-term risk of cancer or other radiation-induced health

problems. Based on this model, AORN specifies that patient

exposure to ionizing radiation should be limited to situations


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where medically indicated and to the anatomical structures

that are being treated.7

For health care workers, the linear-no-threshold model

underlies the principle of keeping occupational radiation doses

as low as reasonably achievable (ALARA).31 The ALARA

concept is of paramount importance for perioperative nurses

and all other personnel who work with ionizing radiation. This

is because if appropriate protective measures are not taken,

personnel can accrue substantial occupational doses of

ionizing radiation over time, leading to a significantly

increased risk of adverse health effects.

The concepts of time, distance, and shielding are essential

to keeping occupational doses of ionizing radiation as low as

reasonably achievable and to achieving dose optimization for

patients.7 Robust data indicate that ionizing radiation dose

increases with increased exposure time, decreases with

increased distance from the radiation source, and can be

attenuated by means of proper shielding. It is therefore useful

to review data on time, distance, shielding, and general

practices for implementing these concepts. Procedure-specific

approaches related to time, distance, and shielding are

discussed in the next section.

Studies indicate that when radiation exposure occurs at a

constant rate, the total dose equivalent received depends on

the duration of exposure. Decreasing exposure time therefore

results in decreased dose. For example, in patients undergoing

treatment for breast cancer, cone-beam CT is used for

external-beam radiation therapy setup and to localize the target

of radiotherapy.32 In a study of two cone-beam CT protocols,

reducing exposure time by half resulted in a 50% decrease in

doses to patients’ organs.32

Physical distance from the source of ionizing radiation is

another important factor in radiation safety. When the distance

from the point source of radiation is doubled, the exposure is

approximately quartered.7 One study used polystyrene models

to estimate x-ray dose to the skin from fluoroscopy in patients

who underwent percutaneous transluminal coronary

angioplasty.33 Results indicated that when the distance

between the radiation source and the phantom was decreased,

estimated dose to the skin increased by 120-180%. The

researchers concluded that these parameters could increase

the risk for skin injuries following this procedure.

Based on these data, AORN recommends that personnel limit

the amount of time they spend near a radiation source when

radiation exposure is possible, and that the radiation

equipment operator give a verbal warning before activating

the equipment.7

Shielding is used to attenuate direct beam and scatter

radiation. Lead remains the most commonly used and widely

studied material for shielding workers from occupational

radiation doses. Lead of 0.5 mm thickness will attenuate at

least 95% of scattered radiation.34 Numerous lead-based

options for shielding are available on the market, including

lead-lined aprons, skirts, and vests, thyroid shields, gloves,

and mobile rigid shields. Lead-lined garments and devices are

also used to shield patients from scatter or unnecessary direct

beam radiation.

Flexible “lead alternative”

apparel is also sold for radiation

protection. These flexible

garments are advertised as

lighter and more flexible than

lead-lined garments. However,

non-lead alternatives provide

no protection from direct beam

exposure and less protection

from scatter radiation. Some

facilities do not use non-lead

alternatives in part because of

concerns that they might be used to attempt to shield patients

from direct beam radiation. As of 2013, the federal

government did not regulate lead equivalent products used in

aprons and other protective apparel.

AORN specifies that shielding be used whenever possible

to attenuate radiation of potentially exposed personnel.7

Health care workers who assist with radiographic procedures

should wear a wrap-around apron shield if they must stand

with their back to an activated radiation device. If they must

stand near the radiation beam, personnel should shield the

upper legs to protect the long bones and bone marrow from

radiation doses. If they need to stand near the tube, radiation

can be reduced by shielding the upper chest and neck, such as

with a thyroid collar.


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Shielding devices also should be handled carefully and

visually inspected before use.7 Although the Joint

Commission states that protective garments must be checked

annually for defects, at present it does not specify how to do

so. Both tactile and imaging methods can be used to evaluate

protective apparel and other devices, but imaging is generally

more accurate. One strategy for imaging protective lead

apparel is to line aprons and other items up on a CT table and

scan them. This method can identify small pinhole defects that

could easily be missed by tactile examination, and use of CT

also allows garments to be compared over time to assess

changes and better identify tears. In addition, personnel are

not in the room when CT is performed so there is no

associated occupational exposure. To date, there is no

regulation of how companies measure the amount or thickness

of lead in their products and no requirement for companies to

disclose how they perform these measurements. Therefore, it

is advisable to check new lead aprons and other new protective

apparel for defects before they are worn. Finally, technology

such as radio-frequency identification (RFID) locator tags can

be installed in lead-lined aprons and other protective garments.

These devices help prevent garments from being mislaid or

overlooked during annual screenings.

In addition, areas where ionizing radiation is used may be

protected with lead-filled walls, windows, doors, and control

booths. Clear leaded doors are acceptable for shielding rooms

if they are properly constructed. It is advisable to require that

a radiation safety specialist evaluate new construction to be

sure that lead was properly installed. A shielding integrity

check can be performed by obtaining a radioactive source

from the nuclear medicine department, placing it inside the

shielded room, and then using a survey meter to measure

radiation levels from outside the room to determine if ionizing

radiation is penetrating the walls.

RADIATION SOURCES IN PERIOPERATIVE

PRACTICE

Ionizing radiation plays a key and expanding role in the

perioperative practice setting.1 It is used widely in traditional

ORs, hybrid operating suites, health provider offices,

diagnostic and interventional radiology departments, and

cardiac catheterization suites, among other locales.

Perioperative teams work with ionizing radiation during

procedures such as orthopedic surgery, coronary angiography,

genitourinary procedures, sentinel lymph node biopsy, stent

insertion, shunt and pacemaker placements, peripheral

vascular angioplasty, and low-dose and high-dose

brachytherapy. Such procedures can be lifesaving and can

significantly improve quality of life. This section reviews

perioperative sources of ionizing radiation and recommends

measures for minimizing occupational exposure during

perioperative procedures.

FluoroscopyFluoroscopy is an

advanced medical

imaging technique used

during many types of

surgical and other

invasive procedures.5

Fluoroscopy functions

much like an x-ray video.

A low-intensity x-ray

beam passes continuously

through the patient’s body

and strikes a detector under the patient. This detector converts

low-intensity x-rays to visible light, creating an image

displayed on a computer monitor.

Fluoroscopy is clinically valuable because it produces detailed

images of the body or of instruments or contrast agents as they

move inside the body. However, fluoroscopy also can expose

patients to some of the highest radiation levels of any

radiographic modality.7 This is because unlike conventional

radiography, fluoroscopy produces ionizing radiation

continuously over a duration of minutes.

Improvements in the complexity and capacity of fluoroscopic

equipment have led to the expanded use of fluoroscopy during

a range of procedures.35 Modern fluoroscopy includes both

simple and interventional techniques.1 Simple fluoroscopic

procedures include angiography, catheter insertion and

manipulation, orthopedic joint replacements and fracture

repairs, and gastrointestinal imaging by means of barium

swallow or barium enema. Interventional applications of

fluoroscopy include endografts for treating aortic aneurisms,

vertebroplasty and kyphoplasty for spinal fractures, uterine

artery embolization, and endoscopic biliary and upper urinary

tract procedures.36

Several types of fluoroscopic devices are used in the

perioperative practice setting.1 These include portable C-arms

and fixed fluoroscopy machines used in hybrid operating

suites and cystoscopy rooms. Portable C-arms resemble

portable x-ray units.37 The “C” portion of the unit contains the

x-ray tube, and the chassis houses the generator and video-

storage equipment. Portable C-arms are available in larger and

miniature sizes. A clinician might use a larger portable C-arm

unit to visualize joint alignment and seating during a total hip

replacement or to visualize catheter and drain placement


9

during surgery. Portable miniature C-arms are used during

surgeries that require narrower visual fields, such as re-setting

bones in the extremities.

Miniature C-arms produce less radiation than larger sized C-

arm units.38,39 For example, one study assessed doses of

ionizing radiation created by conventional C-arms during

several types of procedures, and compared these levels to

doses from miniature C-arms used during the same types of

procedures.38 The results indicated significantly less radiation

scatter to the surgeon when miniature C-arms were used, but

no significant difference in radiation exposure of patients.

Based on these findings, the researchers recommended the use

of the miniature C-arm when possible. In another study,

researcher used dosimeters to test exposure levels during 155

simulated procedures in which a miniature C-arm was used

to image a replica upper extremity.39 The results indicated that

scatter was relatively low and that the dosimeter only incurred

a substantial amount of radiation when it was placed in the

direct line of the beam. However, based on the linear non-

threshold model, there is no minimum safe radiation level and

appropriate precautions should be taken during the use of

miniature C-arms and all other radiologic devices.

In some cases, the use of fluoroscopy has caused serious

cutaneous radiation injuries in patients, such as burns that

progressed to large areas of necrotizing erosion.35 Fluoroscopy

is also a significant source of ionizing radiation exposure for

health care workers. In one study, researchers evaluated

occupational exposure to fluoroscopic radiation during spinal

surgery.40 The results indicated that surgeons received an

average of 1,225 millirems (mrems) of ionizing radiation

during 37 minutes of fluoroscopic time. The next highest

exposure measured was for first assistants, who received 369

mrems.

The American Association of Physicists in Medicine (AAPM)

has recently emphasized that technical and clinical advances

in the use of fluoroscopy have outpaced safety-related

education and training initiatives, and credentialing

requirements.35 Because of this, fluoroscopy has been widely

used by both physician specialists and non-physicians who

are not trained or are inadequately trained in relevant

principles of radiation safety. In response to this concern,

AAPM published detailed guidelines in 2012 to help health

care facilities establish fluoroscopy credentialing and

privileging programs.35

During fluoroscopy, AORN recommends that staff

members stand on the image detector side of the unit when

possible to decrease radiation intensity.7 Personnel should

also keep the patient as close as possible to the image detector

and away from the tube. This practice decreases the dose

required to produce an image, decreases scatter, and decreases

the amount of radiation emitted to personnel. Leaded

eyeglasses are also available and may be advisable if the

health care worker must stand within 24 inches of the x-ray

beam during fluoroscopic procedures.

Hybrid SuitesHybrid operating suites incorporate advanced imaging

equipment into the sterile OR setting.41 This approach

facilitates minimally invasive surgery and allows the

interdisciplinary integration of surgery with endovascular

approaches and other interventional techniques.41,42 Examples

of procedures performed in hybrid suites include hybrid

coronary revascularization, transcatheter valve replacement

and repair, and placement of stents or grafts in the thoracic

aorta.41

High-powered fixed angiography systems are a centerpiece

of many hybrid suites. These systems use a high frame rate

and power output, and have superior imaging capacity

compared to mobile C-arms.43 For example, fixed

angiography systems are used to image the moving heart

during cardiac surgery. Some hybrid ORs are equipped with

other advanced imaging modalities, such as CT and magnetic

resonance imaging (MRI).

Hybrid ORs offer numerous potential advantages, but also

present special challenges with regard to radiation safety. To

minimize ionizing radiation exposure for staff and optimize


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doses for patients, hybrid OR managers and designated

radiation safety officers need to ensure that personnel who

work in hybrid suites are fully trained regarding appropriate

use of fluoroscopic and other imaging and surgical

equipment.42 Radiation protection and dose optimization must

be part of procedure planning. Hybrid suites are covered in

more detail in a separate AORN learner video and study guide.

Cystoscopy RoomsCystoscopy rooms are usually located within surgery suites.

Cystoscopy rooms are designed for genitourinary procedures

such as those of the kidneys, bladder, prostate, and urethra.37

Examples of fluoroscopically guided cystoscopic procedures

include transurethral resection of the prostate and contrast

studies of the kidneys and lower urinary tract. During many

cystoscopic techniques, fluoroscopy is used intermittently

rather than continuously; as a result, cumulative exposure

levels are typically lower than for interventional fluoroscopy.

Conventional radiographyConventional radiography is also used in conjunction with

operative and other invasive procedures to assess the skeleton

and soft tissue.5 Conventional radiography uses higher levels

of ionizing radiation compared to fluoroscopy, but shorter

exposure times, which typically results in much lower levels

of exposure for the patient and less total scatter radiation.

Although the imaging capacity of mobile x-ray units has

improved, image quality tends to be lower than for fixed

units.44 This is because radiographic cassettes in mobile units

cannot be aligned as accurately, and because the distance

between the cassette and the x-ray tube varies.44 In addition,

the output of mobile units is lower, so the range of obtainable

exposures is limited, which may necessitate the use of longer

exposure times.44 For these reasons, mobile radiography

generally should be used only when it is infeasible to examine

a patient on a fixed x-ray machine.

Finally, radiologic technologists, perioperative nurses and

other personnel should not restrain or position patients

manually during radiographic studies because of the risk

of direct beam exposure.7 Instead, personnel should use

traction devices, slings, or sandbags to keep the patient in

position during the study. In rare exceptions when a health

care worker must use his or her hands to position the patient,

the use of protective shielding such as lead-lined gloves

should be considered.

Radiation safety during intraoperative MRIIntraoperative MRI (iMRI) has numerous potential uses

during surgery and other invasive procedures. For example,

iMRI is used during brain tumor biopsies and resections and

to guide placement of deep brain stimulation systems.45,46

Intraoperative MRI helps surgeons visualize, in real time, the

locations of lesions and critical structures of the brain that

must not be damaged.45 This is particularly useful if the brain

or a tumor moves during resection or if cyst decompression

occurs after cerebrospinal fluid is removed.

However, MRI technology is potentially hazardous because

it uses large magnets that create powerful magnetic fields.47

These magnetic fields interact with ferromagnetic materials

such as iron, nickel, and certain types of stainless steel. If

instruments, tools, or other items made from ferromagnetic

material are brought into a MRI room, they can be pulled

suddenly and violently toward the magnet, resulting in a

missile effect.47,48 Examples of ferromagnetic equipment

include oxygen tanks, crash carts, tables, chairs, cleaning

equipment, scissors, laryngoscopes, gurneys, and IV poles.

Serious injuries and death have resulted from bringing

ferromagnetic equipment into the MRI room.48 In one case, a

pediatric patient was killed during routine postoperative MRI

when a non-MR safe oxygen tank was accidentally brought

into the MRI suite.48 The tank became a missile that was

pulled through the air by the magnetic force created by the 10-

ton magnet. The tank then struck the skull of the immobilized

patient, causing fatal cerebral hemorrhage.

Because of these severe hazards, health care organizations

need to establish comprehensive policies and training

activities to ensure the safety of patients and the perioperative

team and the most accurate possible interpretation of images.49

In 2013, the American College of Radiology (ACR) published

updated guidelines on the safe use of MRI.47 These expanded

guidelines highlight the importance of establishing,

implementing, and maintaining current safety policies and

procedures for the use of MRI in all settings. The guidelines

also emphasize that there should be zero tolerance for errors

in settings where MRI is used.47

The ACR guidelines recommend that all sites that use MR for

clinical or research purposes establish and maintain MR safety


11

policies.47 In addition, these sites should name an MRI

medical director to ensure that these policies remain current

with changing technologies and MRI practices. Adverse

events, safety accidents, or near accidents related to the use

of MRI should be reported to the MRI medical director. The

ACR guidelines further address MRI safety issues for specific

groups such as pregnant women, pediatric patients, people

with claustrophobia, and patients with intracranial aneurysm

clips, cardiac pacemakers, or implantable cardioverter

defibrillators.

The ACR guidelines also specify how a facility should restrict

access to its MRI site.47 In total, the ACR recommends four

access zones that restrict the movement of patients and

personnel based on increasing levels of risk:

• Zone I is where MRI poses no risk and patients are

permitted to move freely. An example of a Zone I area

is an outpatient entrance, reception, and waiting area

for an MRI suite. Zone I channels patients and staff to

the prescreening area and helps restrict further access

to the MRI suite.47

• Zone II serves as an interface or buffer zone between

Zone I and the highly controlled inner zones III and

IV. In Zone II, patients can interact with health care

personnel and move around under supervision. An

example of a Zone II area is an MRI screening area in

which health care personnel verbally assess patients

and obtain medical and radiation histories.47

• Zone III has severely restricted access for both

patients and non-MRI staff. This is because the

presence of objects or equipment made from

ferromagnetic substances can result in serious injury

or death as a result of electromagnetic interactions

with the scanner’s magnets. The ACR guidelines

stipulate that MRI staff must strictly control access to

Zone III and that this zone should be physically

restricted from public access by means of key locks

or passkey locking systems.47

• Zone IV is the MRI scanner magnet room itself. By

definition, it is always located within Zone III. Zone

IV is under severely restricted access.47

The MRI-integrated OR should be considered a high-risk zone

in which there is no room for error.50 Several measures can

promote the safest possible use of iMRI. For example, a health

care organization can create a specific safety manual and

implement a series of checklists and protocols for use of iMRI

and actions to take in case of emergency.50 All personnel who

work with iMRI can be required to undergo appropriate MRI

safety training and to use the surgical MRI safety manual and

checklists. Finally, an on-duty safety nurse can be assigned to

screen patients and staff and to ensure that policies and

procedures are appropriately followed at all times when iMRI

is used.

PATIENTS AS SOURCES OF RADIATION

EXPOSURE

In some situations, patients themselves must be regarded as

potential sources of ionizing radiation exposure. Patients who

have received therapeutic radionuclides, for example, are

potential sources of occupational radiation exposure until the

radionuclide has decayed or been eliminated from the body.

Patients who have undergone iodine-131 thyroid therapy for

hyperthyroidism or thyroid cancer or temporary or permanent

brachytherapy for cancer can expose perioperative nurses and

other health care workers to ionizing radiation if appropriate

precautions are not taken.1 AORN recommends that safety

protocols related to these patients be overseen by a

radiation safety officer.7 In addition, several specific

radiation safety practices should be followed.

When body fluid or tissue is removed from a patient who has

had a diagnostic nuclear medicine study or sentinel lymph

node biopsy, the samples should be labeled as radioactive and

handled in compliance with standard precautions and radiation

safety procedures.7 These procedures should be based on

government regulations and recommendations.

Before transferring patients who received therapeutic

radionuclides in the OR, perioperative personnel should first

notify the staff receiving the patients about the radiation

source and its anatomical location.1 Radiation precautions

should then be followed during transfer.

Precautions are also necessary when working with patients

who have received permanent or temporary radioactive

implants.1 An example of a permanent radioactive implant is


12

the placement of radioactive seeds (radioactive material in the

form of micropolymer beads, also known as microspheres)

into organs.1 These procedures are used to treat diseases such

as liver or prostate cancer. The microbeads are infused through

a catheter, travel through the arterial system, and lodge in the

hepatic capillary bed. An interventional radiologist usually

performs this procedure. The infusion syringe must be

shielded to decrease external exposure. In addition,

precautions are needed to prevent spillage of the microspheres,

and universal precautions should be practiced to protect staff

from internal exposure.

An example of a temporary radioactive implant is eye plaques,

which are used in the treatment of choroidal melanoma.1 For

eye plaque implantation, radionuclide seeds are placed in a

silastic insert, which is secured to a disc (or plaque) and

sutured next to the tumor. Plaques are made of gold to reduce

scatter radiation to the optic nerve, choroid, and retina, and

typically are removed after several days.

AORN specifies that manufacturers’ written instructions

be followed when preparing eye plaques.7 In addition, if

implants are sterilized in-house, the manufacturer’s written

recommendations should be followed and the process should

be overseen by a radiation safety officer or designee. Plaques

also should be kept secure and tracked at all times.

DOSE LIMITS AND REGULATIONS

Because of the health risks of radiation exposure, governments

regulate the use of radiation devices and the activities of

radiation safety programs and personnel. Many health care

organizations designate radiation safety officers who supervise

radiation safety programs and ensure that staff and patients

are appropriately protected. Radiation safety officers also

determine which personnel are in frequent proximity to

ionizing radiation, how occupational exposure should be

monitored and recorded, and who should wear monitoring

devices to assess radiation exposure. These activities must be

performed in accordance with federal, state, and local

regulations.

At the federal level, the United States Nuclear Regulatory

Commission (NRC) requires radiation protection programs to

use procedures and engineering controls that keep radiation

doses as low as reasonably achievable.31 The NRC also sets

radiation dose limits for occupational exposure and exposure

of members of the public.

Occupational dose limits for adults are:31

• Total body: 5 rems per year

• Lens of the eye: 15 rems per year

• Skin: 50 rems per year

• Extremities: 50 rems year

In the event that minors are employed, their annual

occupational dose limits are 10% of the dose limits for

adults.31

The NRC also sets dose limits for members of the public,

defined as people who do not work directly with ionizing

radiation and have not received radiation safety training.31

Dose limits for these people are 0.1 rem per year and less than

0.002 rem in any hour. These are the maximum doses that an

individual should receive from any operation or facility that

is licensed to use ionizing radiation.

States, and in some cases local governments, also regulate the

use of radiation in health care settings. However, state

regulations vary considerably in terms of licensure

requirements for health care facilities that use radiation and

requirements for registering radiation devices and training

both physicians and non-physicians who work with radiation.

In cases where state regulations are stricter than federal

regulations, state requirements must be followed. The

American Association of Physicists in Medicine and the

Conference of Radiation Control Program Directors have

published an online interactive map of radiation control

programs in the United States.

DOSIMETRY

Dosimeters, commonly known as badges, are used to monitor

radiation doses to health care workers and other personnel

who work in settings where ionizing radiation is used. Federal

regulations require that radiation doses be monitored if an

occupational dose is likely to exceed 10% of the limit of 5

rems per year, regardless of the practice setting.31 However,

states and localities also regulate dosimeter use and may have

more stringent requirements. These stricter regulations must

be followed if they are in place.


13

In addition to following federal, state, and local regulations

on who must wear a dosimeter, some radiation safety officers

elect to provide dosimeters to everyone who requests them.

This approach allows health care workers to determine their

cumulative radiation dose in the future if they want, even if

they are not expected to exceed 10% of the annual dose limits.

Badges are the most accurate source of data on a cumulative

occupational radiation exposure levels, and as such they

should be worn in careful accordance with radiation safety

protocols.1,7 Several practices should be followed to increase

the accuracy of dosimetry data. Badges should be used only

at work, not taken home where they could be lost, forgotten

when returning to work, or accrue exposure to environmental

sources of ionizing radiation. Badges also should be treated

as an individual record of radiation exposure and not left on

aprons or other protective garments when not in use.

Regulations related to radiation monitoring are enforced by

state programs or the NRC. When two dosimeters are used,

the most common practice is for one to be worn inside the

leaded apron to measure whole-body exposure, and the other

to be worn on the collar outside the apron to measure exposure

to the head, neck, and lens of the eye. When only one

dosimeter is used, AORN recommends that all personnel

wear it on the same area of the body.7 Staff members might

use a single collar dosimeter or a chest dosimeter, for example.

In addition, ring dosimeters might be required for personnel

who handle radioactive material or who are otherwise at risk

of exposing their hands to ionizing radiation in the workplace.1

An example is an interventional cardiologist who performs

catheterization procedures.

Personnel who are involved with fluoroscopic procedures

should wear at least one dosimeter that is made by a vendor

certified by the National Voluntary Laboratory

Accreditation Program.7 Dosimeters that meet this

requirement include film badges, thermoluminescent

dosimeters, and optically stimulated luminescent (OSL)

dosimeters.1 Thermoluminescent and OSL badges are more

durable and OSL dosimeters have the widest useful dose range

(0.001 rem to 1000 rem). In addition, ring dosimeters are used

to assess radiation to the extremities. Ring dosimeters are

required for people who are likely to meet or surpass the

annual dose limit to the extremities of 50 rem.31

If a dosimeter’s readings are higher than expected, it can be

helpful to consider some basic troubleshooting questions. For

example, if a badge was accidentally left on an apron, it might

have been irradiated when someone else used the apron, or if

the apron was placed on a table when service engineers were

testing or repairing ionizing radiation equipment. In other

cases, badges have even accidentally been included in checked

luggage that is directly exposed to ionizing radiation at the

airport. High dosimeter readings also might be recorded if a

dosimeter is worn for much longer than the designated wear

period or if a dosimeter that was lost is found, turned in, and

read.

The use of dosimetry during pregnancy is an important topic.

If a health care worker becomes pregnant, she has the option

to notify the radiation safety officer at her place of

employment.1 This is called declaring the pregnancy. The

rights of workers with declared pregnancies with regard to

radiation exposure are federally defined. The NRC dose limit

for an embryo or fetus is 0.5 rem for the entire gestation

period, and work restrictions are required if an embryo or fetus

is expected to receive more than this dose.31


14

To assess fetal dose, a dosimeter should be worn on the

abdomen at waist level beneath the shielding apron.1 In

addition, some health care facilities use aprons designed for

pregnant workers that include 1 mm of lead in the abdominal

region and 0.5 mm throughout the rest of the apron.1 For

personnel who are pregnant, dosimeters should be read

monthly, not quarterly.7

If the dose equivalent to the embryo or fetus exceeds 0.5 rem

(500 mrem) or is within 0.05 rem of the dose limit by the time

a woman declares her pregnancy to the radiation safety officer,

the NRC licensee is considered in compliance with NRC

regulations if any additional dose to the embryo or fetus is less

than or equal to 0.05 rem for the rest of the pregnancy.

The gestation period is assumed to be 10 months, meaning

that the monthly dose limit is 50 mrem. Monthly fetal

dosimeter measurements should be closely monitored. If a

spike in exposure is observed, it should be proactively

investigated and addressed even if the monthly exposure limit

has not been reached. This is an example of how ALARA is

applied in the workplace.

RADIATION SAFETY FOR PATIENTS

Radiation safety practices have undergone increased scrutiny

during the past several years.51,52 This stems from awareness

of marked increases in the public’s exposure to ionizing

radiation in the United States and elsewhere. In 2006, for

example, reported levels of cumulative radiation exposure for

US residents was more than seven times greater than during

the early 1980s, according to a report by the National Council

on Radiation Protection and Measurement.51 The Council

noted that the majority of this increase was attributable to the

increased use of CT and nuclear medicine. These modalities

are invaluable clinical tools that also expose patients to

relatively high levels of ionizing radiation, particularly with

repeated use.

Analyses of cumulative ionizing radiation exposure elsewhere

correlate with findings from the United States. For example,

a recent study in Italy reported that between 1970 and 2009,

ionizing radiation exposure increased approximately 155%

for patients hospitalized with ischemic heart disease.52 The

study’s authors attributed this rise to the increased use of CT

and invasive fluoroscopy in this patient population.

Increasing exposure to medical doses of ionizing radiation can

have measurable adverse consequences. In the United States,

it has been estimated that 0.02-0.4% of CT scans have been

associated with the subsequent development of cancer in

patients.53 One risk modeling analysis estimated that 29,000

future cancers could be related to CT scans performed in the

United States in 2007.54 The primary procedures implicated

in the risk model were scans of the chest, abdomen and pelvis,

and head, as well as chest CT angiography.

In 2011, in response to concerns about increases in ionizing

radiation exposure, the Joint Commission published a Sentinel

Alert on the use of radiation for clinical purposes.55 This alert

emphasized that diagnostic imaging occurs in a wide variety

of health care settings and that current practice guidelines and

US regulations allow any physician to order tests using

radiation at any dose, without first evaluating radiation

history.55

The Joint Commission made several recommendations in

response to these concerns. These included ordering the right

radiologic tests; optimizing patient doses; expanding the role

of the radiation safety officer to include patient safety;

ensuring that physicians and staff are educated regarding

doses and equipment use; and developing policies and

procedures on use of lead shielding for staff and patients.55 In

addition, the Joint Commission underscored the role of

medical physicists in testing diagnostic imaging equipment

according to pre-determined schedules and the importance of

developing an organizational culture of safety regarding

radiation use.

In 2010, the US Food and Drug Administration also

established the Initiative to Reduce Unnecessary Radiation

Exposure from Medical Imaging.56 This initiative is based on

two major principles— justification and dose optimization.

Justification means that an imaging procedure should be

judged to do more good than harm. Dose optimization means

that patients should receive the lowest radiation dose that

delivers an image of adequate quality for diagnosis or

intervention.

Other researchers have emphasized that increasing levels of

radiation exposure highlight the need for policies guiding the

justification of decisions to order and perform radiographic

procedures, and supporting the careful optimization of

radiation doses.52 The goal of dose optimization for patients


15

reflects the fundamental assumptions of the linear-no-

threshold model: that any level of radiation exposure increases

the risk of stochastic effects such as cancer, and that risk

increases in direct proportion with increased dose.30 To

optimize radiation doses, health care providers must assess a

patient’s radiation history, screen for pregnancy and acute or

chronic conditions that could contraindicate the use of

ionizing radiation, and then minimize radiation doses to the

extent possible while maintaining image quality or the desired

therapeutic benefit.57,58 In the case of CT, for example, this

could mean incrementally reducing the dose while altering

one parameter at a time.58

Perioperative nurses and other team members play an essential

role in protecting patients from unnecessary or excessive

doses of ionizing radiation. AORN recommends that

perioperative team members develop evidence-based

policies and procedures to minimize radiation exposure for

patients and to protect patients from unnecessary radiation

exposure.7 This should be done in collaboration with the

radiation safety staff and members of the radiology

department at the health care facility.

AORN further recommends that safety policies and

procedures specify who in the health care facility has authority

and is responsible for radiation safety, how the facility will

protect patients and staff from unnecessary exposure to

radiation, and what procedures to use when handling and

disposing of tissue and body fluids that may be radioactive.7

These protocols should also specify requirements for wearing

radiation monitoring devices and schedules for testing leaded

protective devices.

The nursing record serves as an important means of protecting

patients from unnecessary or excessive ionizing radiation

exposure. First, perioperative nurses should study their

patients’ medical records and note whether they have

undergone fluoroscopy or other diagnostic or therapeutic

radiographic modalities. If relevant information is found in

the record that could help reduce patients’ risk of radiation

injury, such as fluoroscopic time or the area that was

irradiated, this information should be reported to the treating

physician. Second, measures to protect patients from

radiation exposure should be documented in the

perioperative nursing record.7 Third, during procedures

such as invasive fluoroscopy, ionizing radiation doses

should be continually monitored and recorded.57 This

practice allows clinicians to assess the total dose received and

to assess the risk of deterministic effects such as cutaneous

radiation injury.

Patients also should be screened before undergoing procedures

that use ionizing radiation to ensure they do not have

substantial amounts of residual radioactive material in their

bodies, such as from recent procedures involving nuclear

medicine or radiation oncology.7 If significant amounts of

material remain, it may be necessary to delay additional

procedures in which ionizing radiation is used.

In addition, all reasonable efforts should be made to reconcile

incorrect needle, sponge, or instrument counts before imaging

is used to try to locate missing items.7 If imaging must be used

for this purpose, total exposure time should be kept to a

minimum.

Radiation exposure also should be minimized for patients by

keeping all extraneous body parts out of the primary radiation

beam and by placing lead shielding between the radiation

source and the patient to help prevent radiation injury.7 Lead

shielding should not be placed under the patient so that the

patient is between the lead shield and the radiation source, as

this practice can actually increase radiation exposure by

increasing scatter.1 Lead shielding also should be used to

protect the patient’s ovaries or testes and to protect the

thyroid.7 In addition, female patients of reproductive age

should be asked about the possibility of pregnancy.

To screen patients for acute cutaneous radiation injury,

perioperative nurses should examine patients after


16

procedures to ensure that the skin is intact, smooth, and

free of redness, tenderness, or blistering.7 Cutaneous

radiation injuries also are associated with an increased long-

term risk of squamous and basal cell carcinomas. Therefore,

patients with a history of cutaneous radiation injuries should

have the site examined at least annually.59

CONCLUSIONS AND RESOURCES

Ionizing radiation has numerous potential diagnostic and

therapeutic benefits, and its role in the perioperative practice

setting continues to expand. However, the improper use of

ionizing radiation for medical purposes carries substantial

risks for patients and health care workers, the most serious of

which is cancer. Perioperative nurses play an essential role in

protecting patients and staff from unnecessary or excessive

exposure to ionizing radiation. Because of this, perioperative

nurses need to fully understand the clinical effects of ionizing

radiation and the risks and benefits of various radiologic

modalities.

Radiation safety programs establish practices to minimize

occupational exposure to ionizing radiation, optimize radiation

doses for patients, monitor radiation exposure levels, and

promote patient and staff safety at all times when ionizing

radiation is used. AORN has published several online tools

designed to help health care organizations develop and

implement radiation safety programs. These include a

customizable manual of policies and procedures for

reducing radiation exposure in the perioperative practice

setting and an evaluation tool that provides performance

criteria for perioperative nurses and designated radiation

representative or radiation safety officers. These tools are

available at the AORN website.

• A Policy and Procedure Manual

• Radiation Safety Evaluation Tool


17

GLOSSARY

ALARA - an acronym for As Low As Reasonably Achievable. This is a radiation safety principle for minimizing radiation

doses and releases of radioactive materials by employing all reasonable methods. ALARA is not only a sound safety principle,

but is a regulatory requirement for all radiation safety programs.

Centigray - the international system (SI) unit of radiation dose expressed in terms of absorbed energy per unit mass of tissue.

A centigray is 1 hundredth of a Gray, which is the unit of absorbed dose and has replaced the rad. 1 gray = 1 Joule/kilogram and

also equals 100 rad.

Deterministic effects - health effects, the severity of which varies with the dose and for which a threshold is believed to exist.

Deterministic effects generally result from the receipt of a relatively high dose over a short time period. Skin erythema

(reddening) and radiation-induced cataract formation is an example of a deterministic effect (formerly called a nonstochastic

effect).

Declared pregnant woman - a woman who is also a radiation worker and has voluntarily informed her employer, in writing,

of her pregnancy and the estimated date of conception.

Ependymomas - the most common primary tumor of the spinal cord (especially in adults) and the third most common pediatric

CNS tumor.

Gray - the international system (SI) unit of radiation dose expressed in terms of absorbed energy per unit mass of tissue. A

Gray is the unit of absorbed dose and has replaced the rad. 1 gray = 1 Joule/kilogram and also equals 100 rad.

Ionization - the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons

to form ions, often in conjunction with other chemical changes.

Ionizing radiation - radiation with enough energy so that during an interaction with an atom, it can remove tightly bound

electrons from the orbit of an atom, causing the atom to become charged or ionized

Isotope - one of two or more atoms with the same number of protons, but different numbers of neutrons in their nuclei. Thus,

carbon-12, carbon-13, and carbon-14 are isotopes of the element, carbon, the numbers denoting the mass number of each isotope.

Isotopes have very nearly the same chemical properties, but often have different physical properties. For example, carbon-12

and carbon-13 are stable; carbon-14 is unstable, that is, it is radioactive. A radioisotope is an unstable isotope of an element that

decays or disintegrates spontaneously, emitting radiation. Approximately 5,000 natural and artificial radioisotopes have been

identified.

Linear-no-threshold model - conventionally, the cancer risk from long-lived radicals has been estimated by use of the linear

no-threshold theory (LNT). For example, it is assumed that the cancer risk from 0.001 Sv (100 mrem) of dose is 0.001 times

the risk from 1 Sv (100 rem).

mrems – also called millirem. One thousandth of a rem.

Optically stimulated luminescent (OSL) dosimeter - a personal radiation monitoring device similar to the thermoluminescence

dosimeter but using aluminum oxide to absorb the energy of x-rays and a laser rather than heat to release the stored energy and

measure the dose of ionizing radiation received.

Rad - the original unit developed for expressing absorbed dose, which is the amount of energy from any type of ionizing

radiation (e.g., alpha, beta, gamma, neutrons, etc.) deposited in any medium (e.g., water, tissue, air). A dose of one rad is

equivalent to the absorption of 100 ergs (a small but measurable amount of energy) per gram of absorbing tissue. The rad has

been replaced by the gray in the SI system of units (1 gray = 100 rad).

Radiation safety officer - a person who has the knowledge and responsibility to apply appropriate regulations for protection

against radiation and who assures that radioactive materials possessed under the license conform to the materials authorized by

the license.

Radio-frequency identification (RFId. - the wireless non-contact use of radio-frequency electromagnetic fields to transfer

data, for the purposes of automatically identifying and tracking tags attached to objects.


18

Radionuclide - a radioisotope.

Rem (Roentgen Equivalent Man) - a unit in the traditional system of units that measures the effects of ionizing radiation on

humans.

Scatter exposure - exposure from radiation that, during its passage through a substance, has been changed in direction. It may

also have been modified by a decrease in energy. It is one form of secondary radiation.

Stochastic effects - effects that occur by chance and which may occur without a threshold level of dose, whose probability is

proportional to the dose and whose severity is independent of the dose. In the context of radiation protection, the main stochastic

effect is cancer.


19

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23

1. Ionizing radiation is useful for diagnostic radiology

because

a. it can harm cells.

b. it is of low frequency.

c. it can penetrate tissue.

d. it is absorbed by lead.

2. Choose the TRUE statement

a. Only pregnant women are at risk from ionizing

radiation exposure.

b. The risks of adverse effects from ionizing

radiation exposure decrease with increasing

dose.

c. Anyone exposed to ionizing radiation can have

adverse effects.

d. There is a minimum (safe) threshold for

exposure to ionizing radiation.

3. The primary occupational source of ionizing

radiation exposure in health care facilities is

a. carelessness

b. incorrect positioning of equipment

c. scatter

d. lack of following radiation protocols

4. The three fundamental principles of radiation safety

are

a. regulations, protocols, and consistency.

b. measure, protect, and report.

c. aprons, dosimeters, and leaded walls.

d. time, distance, and shielding.

5. Ionizing radiation doses should be

a. monitored only if the radiation worker is a

minor or is older than 50 years.

b. administered at the highest level necessary,

regardless of a patients’ exposure history.

c. kept as low as reasonably achievable.

d. monitored only if the radiation worker is

pregnant.

6. In health care settings, the primary occupational

source of radiation exposure is

a. lasers.

b. direct beam radiation.

c. MRI scanners.

d. scatter.

7. Lead shielding should be used

a. only at the discretion of a surgeon or

radiologist.

b. whenever possible to attenuate radiation.

c. if a patient or staff person requests it.

d. if an ionizing radiation dose to a patient is

expected to exceed 20 rem.

8. A 0.25 mm lead apron will reduce scattered x-rays

by approximately

a. 15%.

b. 25%.

c. 50%.

d. 95%.

9. Average cumulative radiation exposure has

____________ in the past several decades as a result

of changes in medical applications of ionizing

radiation.

a. decreased

b. increased

c. remained about the same

10. A person who works with radiation is required to be

monitored if

a. he or she asks to be.

b. his or her annual dose is likely to exceed 15

mrem.

c. he or she is likely to exceed 10% of the dose

limit.

d. he or she is likely to exceed 50% of the dose

limit.

POST-TEST


Multiple choice. Please choose the word or phrase that best completes the following statements.

24


11. For adults who work with radiation, the annual

occupational whole body dose limit is

a. 5 rems.

b. 15 rems.

c. 50 rems.

d. 500 rems.

12. For adults who work with radiation, the annual dose

limit for the skin/extremities is

a. 5 rems.

b. 15 rems.

c. 50 rems.

d. 500 rems.

13. For adults who work with radiation, the annual dose

limit for the lens of the eye is

a. 5 rems.

b. 15 rems.

c. 50 rems.

d. 500 rems.

14. For minors who work with radiation, the annual

dose limit is

a. 10% of adult dose limits.

b. 50% of adult dose limits.

c. 75% of adult dose limits.

d. 150% of adult dose limits.

15. The dose limit for a fetus is

a. 0.5 rem during the entire pregnancy.

b. 0.5 rem per month.

c. 5 rem during the entire pregnancy.

d. 5 rem per month.

16. The linear-no-threshold model assumes that the

stochastic effects of radiation

a. are inversely proportional to the dose.

b. are directly proportional to the dose.

c. occur only after a certain level of cumulative

exposure.

d. increase exponentially as exposure increases.

17. All of the statements about the proper use of

dosimeters (badges) in the workplace are TRUE

except for.

a. When one dosimeter is used, all personnel

should wear it at the same place on the body.

b. Badges should be exchanged for assessment

and replaced at pre-determined intervals.

c. Badges should not be taken home at the end of

the workday.

d. The best place to leave a badge when not in use

is on an apron.

18. Badges worn by pregnant personnel should be worn

at waist level and read every

a. week.

b. month.

c. three months.

d. six months.

19. If a health care worker who works with radiation

becomes pregnant, she should

a. stop working with any form of radiation.

b. promptly inform the radiation safety officer.

c. wear a badge at waist level outside her apron.

d. switch from a lead apron to a lead-free

alternative for comfort.

20. The most serious long-term effect of ionizing

radiation exposure is

a. blindness.

b. osteoporosis.

c. cancer.

d. skin injuries.

21. To minimize patients’ risk of adverse effects from

radiation exposure, perioperative nurses should do

all of the following except

a. keep extraneous body parts out of the primary

radiation beam.

b. place lead shielding between the radiation

source and the patient.

c. place lead shielding on the opposite side of the

patient from the radiation source.

d. check medical records before radiographic

procedures to ensure patients do not have

substantial amounts of residual radioactive

material in their bodies.

22. Radiation dose limits for members of the public are

__________ rem per year and less than

_________rem in any hour.

a. 0.1, 0.002

b. 1, 0.02

c. 5, 1

d. 10, 20

25


23. Select the TRUE statement about appropriate

handling of shielding garments.

a. Protective garments should be discarded

annually

b. Leaded eyewear is not indicated unless

personnel are within 6 inches of the primary

beam.

c. Protective garments can be evaluated for

damage by lining them up and scanning them

on a CT table.

d. RFIDs contribute to radioactivity and should

not be used in equipment protecting against

radioactivity.

24. According to the 2013 American College of

Radiology guidelines on MR safety,

a. all clinical and research MR sites should

maintain MR safety policies.

b. an MR medical director should be designated to

ensure that safety guidelines are established and

updated.

c. the MRI suite should be a zero tolerance zone

where adverse events, MR safety incidents, or

near accidents are promptly reported to the MR

medical director.

d. All of the above.

25. Select the behavior or practice that does not conform

with the radiation safety principles of time, distance,

and shielding.

a. Wear a lead-free (lead alternative) garment to

protect against direct beam exposure.

b. Stand on the image detector side of the

fluoroscopy system, away from the tube.

c. Shield the upper legs when standing near the

radiation beam.

d. Stand facing the radiation source or wear a

wrap-around apron.

26. Which is not an appropriate way to decrease

exposure to ionizing radiation from patients?

a. Shield syringes containing radioactive

microspheres (eg, seeds, microbeads).

b. Follow universal precautions when patients are

treated with I-131 for thyroid cancer.

c. When patients have undergone diagnostic

nuclear medicine studies, handle their body

fluids and tissues the same way as for any

invasive procedure.

d. Label sentinel lymph node biopsy specimens as

radioactive in accordance with facility policies.

27. Which cell type or tissue is least sensitive to the

effects of ionizing radiation?

a. Neurons.

b. Bone marrow.

c. Gonads.

d. Embryonic cells.

28. According to American College of Radiology

guidelines on magnetic resonance (MR) safety,

a. patients and non-MR staff should be allowed to

travel freely through Zone II.

b. patients and non-MR staff should have

unrestricted access to Zone III.

c. non-MR staff should have access to Zone II as

long as they are wearing a dosimeter.

d. access to Zones III and IV should be severely

restricted because of the risk of injury or death

from magnetic interactions with ferromagnetic

materials.

29. A woman undergoes standard thoracic radiographs

(x-rays) for a chronic cough and enlarged left

cervical lymph node. Her prior exposure to ionizing

radiation is minimal. The woman later determines

that she was approximately 10 days pregnant when

the radiographs were taken. This woman most likely

has a

a. substantially increased risk of later developing

cancer.

b. very small increased risk of later developing

cancer.

c. substantially increased risk of spontaneous

abortion.

d. substantially increased risk of having a child

with a hereditary defect, such as trisomy 21

(Down’s syndrome).

30. When distance from the point source of radiation

doubles, ionizing radiation exposure is

approximately

a. one quarter of the previous level.

b. one third of the previous level.

c. the same as before.

d. twice the previous level.


26

1.c

2.c

3.c

4.d

5.c

6.d

7.b

8.d

9.b

10.c

11.a

12.c

13.b

14.a

15.a

16.b

17.d

18.b

19.b

20.c

21.c

22.a

23.c

24.d

25.a

26.c

27.a

28.d

29.b

30.a

POST-TEST ANSWERS


radiation safety in perioperative practice · the long-term health effects of ionizing radiation...

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