Sensitivity to radiaiton calculating pt dose
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Sensitivity to Radiaiton & Calculating pt dose. Stat ch 8 Bush ch 40. Tissue and Cell Sensitivity to Radiation. Most Sensitive: Reproductive organs Blood-forming organs Skin Bone and teeth. Least sensitive : Muscle Nervous system. Tissue Radiation Sensitivity.

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Sensitivity to Radiaiton & Calculating pt dose

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Sensitivity to radiaiton calculating pt dose

Sensitivity to Radiaiton&Calculating pt dose

Stat ch 8

Bush ch 40


Tissue and cell sensitivity to radiation

Tissue and Cell Sensitivity to Radiation


Tissue radiation sensitivity

Most Sensitive:

Reproductive organs

Blood-forming organs

Skin

Bone and teeth

Least sensitive:

Muscle

Nervous system

Tissue Radiation Sensitivity


Effects of overdose to humans

Effects of Overdose to Humans


Effects of acute radiation exposures in humans

Effects of Acute Radiation Exposures in Humans


Why cancer risks at low doses are uncertain

Why cancer risks at low doses are uncertain

  • It has been difficult to estimate cancer induction risks, because most of the radiation exposures that humans receive are very close to background levels.

  • At low dose levels of millirems to tens of rems, the risk of radiation-induced cancers is so low,

  • that if the risk exists, it is not readily distinguishable from normal levels of cancer occurrence.

  • In addition, leukemia or solid tumors induced by radiation are indistinguishable from those that result from other causes. 


Relative risk of a 1 in a million chance of death from activities common to our society

Relative Risk of a 1 in a million chance of death from activities common to our society:

  • ·Smoking 1.4 cigarettes in a lifetime (lung cancer)

  • Eating 40 tablespoons of peanut butter (aflatoxin)

  • Spending two days in New York City (air pollution)

  • Driving 40 miles in a car (accident)

  • Flying 2500 miles in a jet (accident)

  • Canoeing for 6 minutes (drowning)

  • Receiving a dose of 10 mrem of radiation (cancer)


Patient dose

PATIENT DOSE

  • RAD

  • MR/MAS PER EXPOSURE - At each kVp level – there is a determined output for each radiographic room

  • EX 70 kvp = 2.5 mr/mas

  • ABD done 70 kVp, 20 mas

  • 2.5 x 20 = 50 mR for that one exposure.

  • LOOK AT formula: mr/mas Ch 8 Stat

  • CH 40 BUSHONG


Sensitivity to radiaiton calculating pt dose

  • LOOK AT CHART: mr/mas PG 210 Stat

  • “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??


Sensitivity to radiaiton calculating pt dose

  • LOOK AT CHART: mr/mas PG 210 Stat

  • “AVE” CHEST EXPOSURE - 2 IMAGES

  • WHAT IS THE PATIENT’S DOSE??

  • OUTPUT OF TUBE NEEDED:

  • PA Chest = mr/mas = 9.5

  • LAT 110 KVP 20 MAS 16:1 GRID 400 RS 72”


Sensitivity to radiaiton calculating pt dose

  • Which of the following technical factors will create the highest skin entrance dose to the patient?

  • A. 80 kvp 300 ma .5s no filter B. 80 kvp 300ma 1/10s no filter

  • C. 80 kvp 1000ma 1/20s 2.5mm al eq. filter

  • D. 80 kvp 800ma 1/60 sec .05mm al eq filter


Sensitivity to radiaiton calculating pt dose

  • The exposure rate to a tech at 4 feet from the source is 240 m R/hr. What distance would be necessary to reduced the rate below 60 mR/hr?

  • A. 1 foot

  • B. 6 feet

  • C. 2 feet

  • D. 9 feet


Sensitivity to radiaiton calculating pt dose

  • If the exposure at 2 inches = 9 R/min, what is the exposure at 6 inches from the source?

  • A. 1 R B. 5 R C. 3 R

  • D. 81 R E. 60R


Sensitivity to radiaiton calculating pt dose

  • If 85 kvp, 400ma 0.12s = 150mR - what is the mr/mas?

  • A. 0.32

  • B. 3.1

  • C. 33.1

  • D. 17.6


Sensitivity to radiaiton calculating pt dose

  • Primary radiation barriers must be at LEAST how high (in feet)?

  • A. 5

  • B. 6

  • C. 7

  • D. 8


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