RT 123 INTRODUCTION & Review of Radiation Protection (Merrills Ch. 2) WK #3

MARIE & PIERRE CURIE 1898 “NAMED RADIOACTIVITY” DEVELOPED A RADIATION DETECTOR 1914 (WW1) DEVELOPED A MOBILE RADIOGRAPHY X-RAY “CAR” TO TAKE XRAY IN THE BATTLE FRONTS TRAINED 150 “TECHNICIANS” TO OPERATED CARS

Early measurement of Radiation Skin dryness & erythema AKA radiodermatitis Ulcers formed Cataracts Cancers

DIAGNOSTIC RADIOLOGY STATIC – STILL SHOTS DYNAMIC XRAYS IN MOTION FLUOROSCOPY

STANDARD VS SI UNITS R - C/kg Rem - Sievert Rad - Gray

100 R = 1 C/kg 1Rad = 1/100 Gray 1 Rem = .01 Sievert (Rad + QF = REM) measurement 100 R = 1 C/kg 1Rad = 1/100 Gray 1 Rem = .01 Sievert (Rad + QF = REM) 1 REM = 10 mSv 1 Rem = 1000mRem

How dangerous the type of radiation is Quality Factor How dangerous the type of radiation is Alpha + fast neutrons = 20 X-ray, Beta, Gamma . = 1

REM IS A PRODUCT OF THE QF x RAD

Why did the bunny die?? BUNNY A Received 200 rads BUNNY B

Why did the bunny die?? BUNNY A 200 rads of X-RAY = 200 RADS BUNNY B 200 rads of alpha = 4000 rads

Permissible Occupational Dose Annual dose: 5 Rem / year 50 mSv / year Cumulative Dose 1rem x age 10mSv X age

Occupational Dose ANNUAL LIMITS WHOLE BODY = 5 REMS / 5000mRem LENS OF THE EYE = 15 REMS EXTREMITIES = 50 REMS

OCCUPATIONAL EXPOSURES 5 REMS / YEAR BUT NOT TO EXCEED 1.25 REM/QUARTER AVERAGE ACTUAL EXPOUSRE IS APPROXIMATELY 50 mrem/year OLD “MPD 5(Age – 18)”

PUBLIC EXPOSURE 10 % OF OCCUPATIONAL NON MEDICAL EXPOSURE .5 RAD OR 500 MRAD UNDER AGE 18 AND STUDENT .1 rem 1 mSv Pg 98 RTA BOOK

CARDINAL RULES OF RADIATION PROTECTION TIME DISTANCE SHIELDING

ROOM SHIELDING PRIMARY SHIELD – PRIMARY BEAM DIRECTED AT WALL 1/16 LEAD - 7 FEET HIGH

ROOM SHIELDING SECONDARY – NO PRIMARY BEAM 1/32 LEAD CONTROL BOOTH (SECONDARY) BEAM SCATTERS 2X BEFORE HITTING LEAD WINDOW – 1.5MM LEAD EQ

MONITORING CONTROLLED AREA – Used by occupationally exposed personnel (monitored) 100mrem / WEEK UNCONTROLLED AREA – PUBLIC 2 mrem per week*

SHEILDING TECHNOLOGIST . 25 mm LEAD LEAD APRON, GLOVES THYROID SHIELD, GLASSES PATIENT – GONAD SHEILDING . 5 mm LEAD

GONAD SHIELDING MUST BE . 5 MM OF LEAD MUST BE USED WHEN GONADS WILL LIE WITHING 5 CM OF THE COLLIMATED AREA (RHB) KUB. Lumbar Spine Pelvis male vs female shielding

TYPES OF SHEILDING FLAT /CONTACT SHAPED SHADOW

               

                  

Personnel Monitoring Devices Film Badges TLD / POSL Pocket Dosimeter Ring Badge

MEASUREMENT FILM BADGE TLD POSL POCKET DOSIMETER ABOVE 10 MREM NOT ACCURATE

REM IS A PRODUCT OF THE QF x RAD

Pregnancy & Embryo Mother – occupational worker (5 rem) Baby – (500 mRem) .5 rem/ year .05 rem/month 5 mSv .5 mSv / month

Declared Pregnant Worker Must declare pregnancy – 2 badges provided 1 worn at collar (Mother’s exposure) 1 worn inside apron at waist level Under 5 rad – negligible risk Risk increases above 15 rad Recommend abortion (spontaneous) 25 rad (“Baby exposure” approx 1/1000 of ESE) www.ntc.gov/NRC/RG/08/08-013.html

Pregnant patient ALWAYS ASK LMP before exposure made “10-day Rule” No longer used “Grace period” of implantation STATE – Beam 5 cm within gonads

PREGNANT PATIENTS ASCERTAIN LMP - IF FETUS IS EXPOSED PHYSICSTS WILL NEED INFORMATION: WHICH XRAY MACHINE USED (MR/MAS) # OF PROJECTIONS (INC REPEATS) TECHNIQUE FOR EACH EXPOSURE SID PATIENT MEASUREMENT AT C/R FLUORO TIME & TECHNIQUE USED PHYSICIST WILL CALCULATE FETAL DOSE

RADIATION DOSE TO PATIENTS ESE - ENTRACE SKIN EXPOSURE (MEASURED BY A TLD) SKIN DOSE GONADAL DOSE BONE MARROW DOSE (MEAN GLADULAR DOSE- MAMMO)

AP VS PA EXPOSURE/ESE

SOMATIC & GENETIC STOCHASTIC VS NON STOCHASTIC A = STOCHASTIC “CHANCE” EFFECTS GENETIC, LEUKEMIA, CANCER DIAGNOSTIC RADIOLOGY B= NON-STOCHASTIC THRESHOLD EFFECTS DETERMINISTIC SOMATIC EFFECTS SKIN ERYTHEMA, CATARACTS, STERILITY RAD -MALIGNANCIES

GSD 0. 20 mSv or 20 millirem GENETICALY SIGNIFICANT DOSE Takes all of the population into account Annual AVERAGE gonadal dose to population of childbearing age 0. 20 mSv or 20 millirem rem or rad???

REDUCING REPEATS TECHNIQUE CHARTS CAREFUL REVIEW OF TECHNICAL FACTORS REFER TO TECHNIQUE BOOK AND ASK WHEN YOU ARE NOT SURE!

Carlton Ch 13 - p. 208 & 210 & 214 “AVE” CHEST EXPOSURE - 2 IMAGES (Ave – Pt meas 23cm pa 40cm lat) PA 110 KVP 5 MAS 16:1 GRID 400RS 72” LAT 110 KVP 20 MAS 16:1 GRID 400 RS 72” WHAT IS THE PATIENT’S DOSE??

PEDIATRIC EXPOSURE MORE SENSITIVE TO RADIATION THAN ADULTS LIMIT BEAM TIME MAY REMOVE GRID (REDUCE EXPOSURE) AP VS PA COLLIMATION & SHIELDING !!!!!!!!!!!!!!! GENDER DIFFERENCES IMMOBILATION