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SHIELDING: A TIME-HONORED TRADITION

Kristin Beinschroth, BSRS, R.T.(R)

Visiting Professor, California Baptist University

Adjunct Faculty, Chaffey College

kbeinschroth@calbaptist.edu

DISCLOSURE

• I am not an employee or a stakeholder of any of the organizations listed

in this presentation.

• There is no conflict of interest.

• Resources available upon request- email kbeinschroth@calbaptist.edu

OBJECTIVES

• Discuss the time-bound practice of gonadal shielding of patients in

medical imaging.

• Examine new data regarding the practice of shielding.

• Deduce new policies in line with current recommendations from

leading professional organizations in the field of medical imaging.

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HISTORY• Three Cardinal Principles of Radiation Protection:

• Time

• Distance

• SHIELDING

• Where does the idea of shielding come from?

• Early radiation injuries

CURRENT PRACTICES

• ASRT curriculum

• Radiation Protection- Content, Section V.- Application

• Part C.- Cardinal Principles in Protection (Time, Distance, and Shielding)

• Section VI.- Patient Protection

• Part B.- Radiation Safety Practices (Beam Restriction, Shielding, Exposure Factors,

Positioning, Immobilization)

• Objective: “Explain the purpose and importance of patient

shielding.”

CURRENT PRACTICES

• CDPH-RHB

• Health and Safety Code, Div. 104, Part 9, Chapter 8, Article 4, Section 115061

• “(a) In order to better protect the public and radiation workers from unnecessary

exposure to radiation and to reduce the occurrence of misdiagnosis, the

Radiologic Health Branch within the State Department of Health Services shall

adopt regulations that require personnel and facilities using radiation-producing

equipment for medical and dental purposes to maintain and implement medical

and dental quality assurance standards that protect the public health and safety

by reducing unnecessary exposure to ionizing radiation while ensuring that

images are of diagnostic quality. The standards shall require quality assurance

tests to be performed on all radiation-producing equipment used for medical

and dental purposes.”

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CURRENT PRACTICES

• CDPH-RHB

• Health and Safety Code Section 114840

• “The Legislature finds and declares that the public health interest requires

that the people of this state be protected from excessive and improper

exposure to ionizing radiation. It is the purpose of this chapter to establish

standards of education, training, and experience for persons who use X-rays

on human beings and to prescribe means for assuring that these standards

are met.”

CURRENT PRACTICES

• CDPH-RHB Radiation Safety and Protection Program Requirement

Guidance

• “Additionally, the registrant shall use, to the extent practical, procedures and

engineering controls based upon sound radiation protection principles to

achieve occupational doses and doses to members of the public that are “as low

as reasonably achievable”.

• “The registrant must audit the program on an annual basis to ensure it remains

within the scope and extent of activities requiring the program.”

• Other Controls- “The following items should be considered:”

• 1. ….. “gonadal shielding, protective aprons, protective gloves, mobile shields, etc.”

BONTRAGER’STEXTBOOK OF RADIOGRAPHIC

POSITIONING AND RELATED ANATOMY,

9TH EDITION

• Specific area shielding is essential

• When gonads are in or near the useful beam

• When it does not interfere with the objectives

of the exam

• Reduce gonadal dose by 50-90% (when in

primary beam)

• Improper placement of shields is

common and well-documented

• “Although there is evidence that gonadal

shielding may not offer as much

protection as originally anticipated, it is

still recommended and required in some

states to use gonadal shields.”

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INTRODUCTION TO RADIOLOGIC

TECHNOLOGY, 8TH

EDITION

• “Patient exposure can be reduced

tremendously when the radiographer

uses gonadal shielding.”

• “The technologist must take the time and

effort to use shielding as an effective

means of reducing genetic risks for the

whole population.”

• “Gonad shields should be used

whenever the reproductive organs are in

the primary beam if the area shielded is

not necessary for the diagnosis.”

RADIATION PROTECTION IN

MEDICAL RADIOGRAPHY, 8TH

EDITION

• “Gonadal shielding ought to always be

used whenever it will not obscure

necessary clinical information.”

• “Gonadal shielding is used unless it will

compromise the diagnostic value of the

examination.”

• Secondary protective measure only

RADIOLOGIC SCIENCE FOR

TECHNOLOGISTS, 11TH EDITION

The Ten Commandments of Radiation Protection

• 1. Understand and apply the cardinal principles of

radiation control: time, distance, and shielding.

• 8. Use gonadal shields on all people of childbearing

age when such use will not interfere with the

examination.

• “Gonadal shields should be used with all persons of

childbearing age when the gonads are in or near the

useful x-ray beam and when use of such shielding will

not interfere with the diagnostic value of the

examination.”

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BUSHONG CONTINUED• Gonadal Shielding

• Gonadal shielding should be considered for all patients, especially children and

those who are potentially reproductive. As an administrative procedure, this

would include all patients younger than 40 years of age and perhaps even older

men.

• Gonadal shielding should be used when the gonads lie in or near the useful

beam.

• Proper patient positioning and beam collimation should not be relaxed when

gonadal shields are in use.

• Gonadal shielding should be used only when it does not interfere with obtaining

the required diagnostic information.

• “The shield must shadow the gonads without interfering with the

desired anatomy. Improper positioning of the shadow shield can

result in a repeat examination and increased patient dose.”

WHEN SHIELDING GOES WRONG

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AEC/ABC

• Photocells covered with shielding can utilize back up mAs

• 600 mAs, 6 secs- MAXIMUM as regulated

• But you have to set the back up mAs!

• Rule of thumb- 3x what you THINK you will need

• Too much collimation in fluoro leads to increased dose

• ABC system reads that very few x-rays are reaching the input phosphor

• ABC increases dose to compensate for low brightness

• But the system will not be able to penetrate the shield to its specifications!

ARTICLES

• Marsh and Silosky, April 2019, Patient Shielding in Diagnostic Imaging:

Discontinuing a Legacy Practice. American Journal of Roentgenology,

212, 755-757 doi:10.2214/AJR.18.20508

• Asked R.T.s what they would do if their facility adopted a no-shielding

policy

• 86% said they would shield anyway- ZOINKS

• Three main points

• Not for the reason initially intended

• No benefit (negligible)

• Significant risks

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JUSTIFICATION 1

• Patient shielding was intended to alleviate hereditary

risks

• Shielding is justified as a matter of protection from hereditary

risks, not as an overall reduction in stochastic risk.

• Initially implemented these practices in 1976

• U.S. Code of Federal Regulations

• Only cited concern in mutations in germ cells that affect offspring

• 42 years later, no hereditary effects from radiation have ever

been observed in humans.

JUSTIFICATION 2• Patient shielding provides negligible (or no) benefit.

• We have had a drastic reduction in the dose associated with radiography since

1976.

• 1959= AP Pediatric male pelvis ~2.5 mGy, AP pediatric female pelvis ~1.2

mGy

• 2012= “ “ ~0.06 mGy, “ “ ~0.01 mGy

• 96% reduction in dose!

• “To our knowledge, no evidence exists to indicate that a single imaging study

poses any risk to a fetus.”

• Epidemiologic studies do not support the linear non-threshold model under 100

mSv.

• Most data show that biologic effects at low doses of radiation vary substantially from

those of acute doses.

• Hormesis is supported with the J-curve

JUSTIFICATION 3

• Patient shielding introduces significant risks.

• AEC, ABC, ATCM

• Increased repeat rates from obscured anatomy.

• Franzen et. al found that gonadal shields were incorrectly placed for 91% of

pelvic radiographs of girls, and 66% of boys.

• Another study showed that pelvic shields were misplaced in 49% of AP pelvis

and 63% of frog lateral hips.

• Pelvic bony landmarks were obscured by shielding in up to 43% of images.

• Not all exams were repeated, leaving gaps in information.

• Shielding practices are largely supported by a skewed perception of radiation

risk.

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ARTICLES

• Fawcett and Barter, May 2009, The use of gonad shielding in paediatric

hip and pelvis radiographs. British Journal of Radiology, 82(977), 363-70.

doi:10.1259/bjr/86609718

• Shields were used 70% of the time.

• Only 38% of all shields were considered to be positioned accurately.

• For cases where shielding was indicated, an accurately placed shield was present

in just 26%.

ARTICLES

• Frantzen et. al, Feb 2012, Gonad shielding in paediatric pelvic

radiography: disadvantages prevail over benefit. Insights Imaging, 3(1),

23-32, doi:10.1007/s13244-011-0130-3.

• For girls, shield were incorrectly placed in 91% of the cases, for boys

66%.

• With shielding, the reduction in hereditary risk for girls was on

average 6±3% of the total risk for the radiograph; for boys 24±6%.

• Effective dose ranged from 0.008 to 0.098 mSv.

• With modern optimized x-ray systems, benefit of gonadal shielding is

negligible.

ARTICLES

• Kumar et. al, Dec 2018, Gonadal shield; is it the albatross hanging around the neck of

developmental dysplasia of the hip research? Journal of Child Orthopedics, 12(6), 606-

613, doi:10.1302/1863-2548.12.180133

• Only 42.67% of pelvis radiographs used gonadal shielding despite the presence of a

clear protocol.

• Useful anatomical landmarks were obstructed in 58.9% of radiographs with shielding

present.

• Lost diagnostic information was more common in females than males- 68.1% vs.

11.1%, p<0.01

• Gonadal shielding was ineffective at gonadal protection in 73.2% of the pelvises,

with worse protection in females- 78.7% vs. 44.4%

• Essential anatomy was obstructed in all of the adequately protected female pelvises.

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ARTICLES

• Jacklevic (Kaiser Health News), Jan. 2020, That lead apron in the x-ray

room? You may not need it, The New York Times, https://nyti.ms/2tgJpRf

• Advanced Health Education Center (AHEC), Jan. 2018, What would you

do? Stop shielding your patients?, AHEConline Blog,

https://aheconline.blog/2018/01/15/what-would-you-do-stop-

shielding-your-patients/

SUPPORT

• AAPM Position Statement on the Use of Patient Gonadal and Fetal

Shielding

• Policy date- 4/2/2019, sunset date 12/31/2014

• Patient gonadal and fetal shielding during X-ray based diagnostic

imaging should be discontinued as routine practice.

SUPPORT• ACR endorses AAPM Position on Patient Gonadal and Fetal Shielding

(6/6/2019)

• Image Gently ® endorses AAPM Gonadal shielding position

(11/12/2019)

• Board of Directors of the Canadian Association of Radiologists (CAR)

votes to endorse the AAPM Position Statement (10/1/2019)

• Canadian Organization of Medical Physicists (COMP) officially endorse

the AAPM Position Statement (06/25/2019)

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OPPOSITION

• The ASRT Board cannot endorse (at the time) the proposal to

remove gonadal shielding and fetal shielding (07/02/2019)

• Scheduled meeting in the Fall of 2019

• Facilities that have had recent state audits

• Shielding on male pelvises is commonly evaluated by state

inspectors

ARRT CODE OF ETHICS

• 4- The radiologic technologist practices technology founded upon theoretical

knowledge and concepts, uses equipment and accessories consistent with the

purposes for which they were designed, and employs procedures and techniques

appropriately.

• 5- The radiologic technologist assesses situations; exercises care, discretion, and

judgment; assumes responsibility for professional decisions; and acts in the best

interest of the patient.

• 7-The radiologic technologist uses equipment and accessories, employs techniques

and procedures, performs services in accordance with an accepted standard of

practice, and demonstrates expertise in minimizing radiation exposure to the

patient, self, and other members of the healthcare team.

• 10- The radiologic technologist continually strives to improve knowledge and

skills by participating in continuing education and professional activities, sharing

knowledge with colleagues, and investigating new aspects of professional

practice.

CONCLUSION

• AJR Article- Practical Implementation of a no-shielding practice

• A significant departure from how radiology has been practiced for decades.

• Incumbent on health care professionals to help patients feel confident about the

care they receive.

• 1st- Address patients’ concerns when introducing yourself.

• Posters, brochures

• This is intentional, not unintentional

• 2nd- Give technologists discretion to provide shielding in certain circumstances

• Advise patients of potential risk, but ultimately provide shielding if requested

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