Chapter 4 + 10 Flashcards by Taylor Donato

Discovery

-‘wonder rays’ w unknown effect
-lots of experimenting lead to visual somatic effects
-Clarence Daily was first to die at 39 (Edison’s fluoro assistant)

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Dose Limit Term History (1900-Present)

1900-1930 - Skin Erythema Dose - when skin looked red=dose reached
1930-1950 - Tolerance Dose - dose limit before visible damage
1950-1977 - Maximum Permissible Dose - dose thought to be acceptable w/o effects, starting to monitor w PMD measured in REM
1977-1991 - Effective Dose Equivalent (Equivalent Dose) accounts radiation type
1991- Present - Efective Dose Limit - accounts radiation and tissue type

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Occupational Exposure

Rad exposure received by worker in the course of exercising their professional responsibilities

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Early tissue reactions

W/in minutes hrs days weeks after exposure ex. nausea fatigue skin erythema hair loss

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Late tissue reactions

W/in months to years after exposure, potential of creating genetic/inheritable effects ex. cataracts fibrosis organ atrophy reduced fertility

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Stochastic tissue reactions

The exact dose that causes is unknown ex. cancer genetic/hereditary effects

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Exposure (X)

radiation in air, measured w/cutie pie
SI: C/Kg
Trad: R (roentgen)

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Air-KERMA

Kinetic energy released in matter, replaced exposure, amount of radiation in air
SI: J/Kg or Gy(A)

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Absorbed Dose (D)

amount of energy per unit of mass absorbed
SI: Gy(T)

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Conversions

centi: 100
milli: 1000
micro: 1000000

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DAP (Dose Area Product)

-measures air kerma being focused n entire area of pt
-accounts dose and field size
-mGycm2

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Differential Absorption

Affected by 3 things
1. Anatomic Structure (Atomic #) based on composition
2. Mass or Density of tissue (compactness-bone vs lung)
3. KVP - beam quality affects penetrability

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Equivalence of Radiation Damage

1 Gy xray vs 1 Gy alpha will have very different bio effects, so multiplier is assigned called QF (quality factor) or WR (radiation weighing factor)

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LET (linear energy transfer)

the amount of energy transferred on avg by incident radiation to an object per unit length of track through the object
high let=high damage=high QF/WR
low let=low damage=low QF/WR

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Equivalent Dose

accounts the type of radiation (WR)
EQD=D x WR equation
(Sv=Gyt x WR) measurements

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Effective Dose

accounts the type of radiation and tissue (WR, WT)
EFD=D x WR x WT equation
Sv=Gyt x WR x WT measurements

ICRP

International Commission on Radiological Protection
-authority regarding safe use of ionizing rad
-provides protection guidance through recommendations on occupational + public dose limits

NCRP

National Council on Radiation Protection and Measurements
-review recommendations of ICRP + decide how to incorporate into protection criteria
publish dose limit recommendations
-not an enforcement agency

UNSCEAR

United Nations Scientific Committee on the Effects of Atomic Radiation
-protection guidelines
-epidemiologic data to evaluate human + environmental ionizing rad (radioactive materials, accidents etc)

NAS/NRC-BEIR

National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation
-advisory group that review studies of bio effects
-follow up studies on rad events (ex. Japan atomic bomb survivors)

NRC

Nuclear Regulatory Commission
-enforces rad protection standards
-controls manufacture/use of radioactive substances
-licenses users of radioactive materials
-can make unannounced inspections
-writes standards

Agreement States

States that assume responsibility of enforcing rad protection regulations thru their health depts have agreements w the NRC
States may enforce their own laws but most follow whatever is more stringent

EPA

Environmental Protection Agency
-responsible for protecting the health of humans + safeguarding natural env
main area: detection + control of radon

FDA

US Food + Drug Administration
-regulate design/manufacturing of electronic products like diag equipment
-conduct site inspection on xray equipment
-compliance w their standards ensures protection of (non) occupationally exposed persons from faulty manufacturing

OSHA

Occupational Safety + Health Administration -employment monitoring agency + regulations concerning employees -'right to know' of workplace hazards regulates training programs

Radiation Safety Program

-ensures adequate protection of workers and pts -oversees development of policies + procedures -must name radiation safety officer

RSO

Radiation Safety Officer -oversees daily operations and provides formal annual review -develops appropriate rad safety program for facility -maintain all monitoring records for personnel/staff Have authority to -identify rad safety problems -provide corrective action -stop unsafe operations

ALARA

'as low as reasonably achievable' created in 1954 by now NCRP purpose to keep exposure to pt and tech as low as possible

FDA White Paper

each pt should get the right exam at the right time w the right dose focuses on use of safe med imaging devices, informed decision, and increases pt awareness

Consumer-Patient Radiation Health and Safety Act of 1981

establishes minimum standards for accreditation and education programs and ensures rad safely is taught

Radiation Control for Health and Safety Act of 1968

-holds manufacturers accountable to protect public from unnecesary exposure (microwaves, diagnostic equip, etc)

CDRH

Center for Devices + Radiologic Health -conducts + monitors rad control program for all electronic products giving off Em -monitors installation, assembly, maintenance, bio effects, emissions -conducts research on lowering rad exposure

Code of Standards

1. Automatic Collimation + PBL (positive beam limitation) 2. Minimal Amt of Tube Filtration (2.5 mm Al equiv) 3A. Reproducibility - want consistent output at given technique (same one tested 5-10 times w cutie pie) #B. Exposure Linearity - consistent output with same kvp but different ma + s combinations (tested 3-4 times w cutie pie) 4. Accurate beam limitation on fluoro exams 5. Beam on indications - visual and audible 6. Manual back up timers for AEC - stops exposure is automatic exposure control malfunctions

Non-Stochastic/Deterministic/Tissue Reactions

Can determine dose that creates response, somatic effects that can be directly related to dose received, can have threshold dose (amt received w/o reaction

Stochastic/Probalistic

Don't know the dose that correlates to reach a response, any dose could cause the response, no threshold, assume there is no safe dose

ARS

Acute Radiation Syndrome 1. Hematopoietic (1-2Gy) 2. Gastrointestinal (6-10Gy) 3. Cerebrovascular (50Gy +)

Teratogenesis

birth defects from irradiation the embryo/fetus in utero

Mutagenesis

birth defects from irradiating the reproductive calls prior to fertilization

Radiation Hormesis

beneficial consequence of radiation for populations continuously exposed to moderately high levels of rad on a regular basis (ex. Hiroshima bomb survivors have 50% lower cancer rate than general public)