NC Radiation Protection Section- DENR

NC Health Physics Society

ENERGY

Energy

Travels in Waves

High Speed Particles

Ionizingionizes [strips electrons from]

atoms

Non-Ionizingmany other modes of

interaction

Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough energy to remove electrons from

the atom.

Ionization is the process in which a charged portion of a molecule (usually an electron) is given enough energy to break away from the atom.

This process results in the formation of two charged particles or ions:

• molecule with a net positive charge

• free electron with a negative charge

Alpha Radiation ()

• Particle released when the nucleus kicks out 2 neutrons and 2 protons

• Relatively massive

• Relatively slow

• Total charge of +2

Mass number changes by 4 and atomic number changes by 2

Beta Radiation ()

• Particle released when the nucleus changes a neutron into a proton and a beta particle

• Relatively small mass

• Relatively fast moving

• Total charge of -1

Atomic Mass Number remains constant

PN

Gamma Radiation ()

• Pure energy. Released from the nucleus when an alpha or a beta is emitted

• No mass

• Speed of light

• No charge

NO CHANGE

Courtesy of David C Howell, Radiation Safety Officer-Wake Forest University-Baptist Medical Center

Property of some atoms to spontaneously give off energy as particles or rays

Caused by instability in the atom’s nucleus or an excess of energy

Radioactive atoms try to achieve stability by throwing off Protons or Neutrons, other

particles, or by releasing excess energy in other forms

StableRadioactive Decay Process

Time required for the disintegration of one-half of the radioactive atoms that are present in a given amount

• Uranium-238 (In soil)– 4.5 Billion years

• Potassium-40 (in soil and body)– 1.3 Billion years

• Carbon-14 (In all living tissue)– 5730 years

• Hydrogen-3 (in all water)– 12 years

• Radium-226 (In soil - produces radon)– 1600 years

• Radon-222 (in soil and air)– 3.8 days

• Polonium-214 (radon progeny that decays in lungs)– 164 microseconds

Dose = Rad/ Gray (Gy) 1Gy = 100 rads

Dose Equivalent = Rem/ Sievert (Sv) 1Sv = 100 rem

Exposure = Roentgen (R)

Examples of Radiation Dose from Medical Radiation Exposures– Chest X-ray: 8 mrem (0.08 mSv)– Head CT scan: 111 mrem (1.11 mSv)– Barium Enema: 406 mrem (4.06 mSv)– Extremity X-ray: 1 mrem (0.01 mSv)Source: NCRP Report 100

Risk

Dose(in addition to natural background radiation)

Most sensitive cells:

Rapidly dividing cells(Small intestines, bone marrow, hair, fetus)

Least sensitive cells:Slowly dividing cells

(brain, nerves)

Acute Somatic

• Immediate effects to the organism receiving the dose

Delayed Somatic

• Effects that appear years later to organism receiving the dose

Genetic

• Effects that appear in offspring

Symptoms of Radiation Sickness

• Nausea and vomiting • Diarrhea • Skin burns (redness, blistering) • Weakness, fatigue, exhaustion, fainting • Dehydration • Inflammation of exposed areas (redness, tenderness, swelling, bleeding) • Hair loss • Ulceration of the oral mucosa • Ulceration of the esophagus, stomach or intestines • Vomiting blood • Bloody stool • Bleeding from the nose, mouth, gums, and rectum • Bruising • Sloughing of skin • Open sores on the skin

Health Effect Organ Dose (rad)

Blood cell depression Bone Marrow 50

Reversible skin effects Skin 200

Permanent sterility Ovaries 250 – 600

Vomiting GI 300

Temporary hair loss Skin 300 – 500

Permanent sterility Testis 350

Skin erythema Skin 500 – 600

Dose Health Effect

>300,000 mRAcute

Exposure

• Destroy cell tissue almost immediately• Death results within a few days or weeks for more than half the exposed population

>5,000 mRHigh Level Exposure

• Increase risk of infection, cancer, & potentially cause genetic damage to person &/or offspring• Cataracts, premature aging, hair loss, skin burns, & shortened life span

Low-Dose Effects

• Difficult to determine because cells can repair some damage & difficulty to identify cause of cancers as due to radiation exposure verses environmental/ genetic factors

Time

Distance

Shielding

Containment

• Well logging

• Test pipes & welds

• Control thickness of sheet products

• Cold sterilize plastics, pharmaceuticals, cosmetics, & other heat sensitive products

• Security checks (luggage)

• Prove authenticity of old paintings

• Detect pollution

• Food treatment comparable to pasteurization– Kills pests/microorganisms without food degradation– Controls sprouting

• Does not make the food radioactive• FDA Approved• Must be labeled

Good information about food irradiation:http://uw-food-irradiation.engr.wisc.edu/Facts.html

• Smoke Detection Equipment• Self-powered Lighting in Exit Signs• Lighted Aircraft Instrumentation• Pharmaceutical Detection• Bomb/Weapons Detection• Scanning and Surveillance

Equipment• Theft Deterrent Systems

• Television sets accelerate electrons to make the picture on the screen and in the process produce a few low energy x-rays.

• Some more products or services: long lasting light bulbs, building materials, and luminous dials, among many others.

• Eliminate dust from computer disks & audio & video tapes

• Sterilize baby powder, bandages, cosmetics, hair products, & contact lens solutions

• Control thickness of sheet products• Attach a non-stick surface to pans• Brighten porcelain in false teeth

• Small radioactive sources have provided heat and electrical power for space probes for decades

• Radioactive power supplies have allowed space craft to explore the outer solar system, too far from the sun for solar panels to be effective

Map of U.S. Nuclear Regulatory Commission Regions

• X-radiation– Radiographs– Fluoroscopy– CT scan

• Nuclear Medicine

Generally low dosesShort-time exposures

Radiotherapy (Direct radiation beam)Gamma raysElectron beamsX-radiation

Brachytherapy (Radiation from internally deposited radioactivity)Removable seeds (long half-life)Permanent seeds (short half-life)

Generally high dosesShort to long time exposures

• Radioactivity remaining after atmospheric nuclear weapons testing• Less than 0.01 mSv (1 mrem)/yr • Long-lived radionuclides:

– Cesium-137: 30 year half-life• Mimics potassium - found in muscle

– Strontium-90: 29 year half-life• Mimics calcium - found in bones

Leukemia is among the greatest of afflictions that are passed on to the offspring of survivors

http://www.serendipity.li/more/atomic.html

U.S. Ecology FacilityRichland, WA

Chem Nuclear FacilityBarnwell, S.C.

Envirocare FacilityClive, UT

Thank you for your attention

Any Questions?