Exam 4 Ch. 40- Occupational Radiation Dose Management Flashcards
high in occupational exposure-
interventional radiology
cardinal principles in occupational exposure-
time, distance, & shielding
time-
-biggest issue
-highest occupational & interventional exposure (fluoro/interventional)
distance-
tech should remain as far as practical from patient
shielding-
-maximize when possible
-protective curtain & bucky slot cover (shields rad & dr)
scatter during fluoro more intense when-
the tube is over the patient
average whole body exposure/dose-
0.7 mSv/yr
receiving less than minimum-
53%
receiving less than 1 mSv/yr-
88%
receiving more than 50 mSv/yr-
0.05%
occupational exposure high in-
-fluoro
-portables
-specials (extremities)
with II under the table-
-image quality is improvised
-occupational exposure is increased
occupational exposure low in-
mammo & CT
occupational exposure lower in mammo because-
lower kVp so scatter is reduced
occupational exposure low in CT because-
beam is so tightly collimated & technologist doesn’t have to be in room
occupational exposure in surgery-
Drs., nurses, & other technologists
goal of NCRP (3)-
-formulate & disseminate information
-guidance
-DL recommended that reflects most current scientific thinking
early dose limits were based on-
threshold doses
current dose limits prescribed for-
-specific organs
-whole body dose
although exposure should be kept ALARA, there’s-
no patient dose limit
current dose limits are based on-
linear, non-linear threshold dose response relationship
consider the level of exposure acceptable as-
occupational hazard
effective dose concepts taken into consideration-
-verifying effects of radiation exposure
-varying degree of radiosensitivity
wearing a lead apron reduces radiation dose to-
some tissues, nearly 0 (dose limits rarely exceeded
w: a collar monitor, a person who works in fluoro would need to-
convert effective dose readings due to wearing lead apron
whole body dose limit-
-50 mSv/yr
-5,000 mrem/yr
-5rem/yr
skin & extremities dose limit-
-500 mSv/yr
-50 rem/yr
dose limits in skin & extremities are-
-not normally a concern in diagnostic radiography
-very high levels & shouldn’t be reached if radiation safety is practiced
frequent public exposure dose limit-
-1 mSv/yr
-100 mrem
equivalent public exposure dose for lens of the eye-
-150 mSv/yr
-1500 mrem/yr
skin, hands, & feet public exposure dose limit-
-500 mSv/yr
-5000 mrem/yr
public exposure is accomplished w:-
barriers
educational public exposure dose limit-
students under 18 may not receive more than 1 mSv (100 mrem) for course of their training
reduction of occupational exposure mostly w:
-ALARA
-time
-distance
-shielding
monitoring occupational is done primarily w:-
monitoring devices
radiation monitor offers-
NO PROTECTION against exposure
monitoring devices (3)-
-Thermoluminescence Dosimeter (TLD)
-Pocket Ionizingg Chamber
-Optically Stimulated Luminescence (OSL)
Thermoluminescence Dosimeter (TLD)
-lithium fluoride more sensitive & accurate, but more expensive
-Provides no permanent record.
-Can be worn up to 1 yr.
Pocket Ionizing Chamber-
are accurate, but can’t be used for more than a couple days
Optically Stimulated Luminescence (OSL)-
-most sensitive, accurate, & appx same size as TLD
-Can only be measured 1x
-Has ability to determine exposure of radiation received
Reduction of Occupational Exposure- Protective Apparel (4)-
-must be- 0.25 mm Pb of equivalent
-must be checked for cracks at least 1 per year
-position of tech. during exams should be as far from scatter as practical
-patient holding should be kept to minimum
pregnant technologist-
-first inform supervisor
-Becomes declared pregnancy
-DL is 5 mSv for gestation pd.
-wear monitor @ waist.
management decisions for a pregnant technologist (3)-
-training
-periodic in-service
-counseling during pregnancy
