Exam 4 Ch. 39- Patient Radiation Dose Management

Question 1

all medical physics activity is directed in some way to-

Answer 1

minimizing radiation exposure

Question 2

2 reasons for increased attention of radiation use-

Answer 2

-overall increase in use of x-ray imging.
-acute affects seen after interventional studies & stochastic effects in the public

Question 3

average mammo patient dose-

Answer 3

ESE appx. 8 mGya/view

Question 4

digital imaging replaces film/screen-

Answer 4

further dose reduction is limited by kVp

Question 5

grids increase-

Answer 5

dose to breast tissue

Question 6

grid ratios most common in mammo-

Answer 6

4:1 & 5:1 w bucky factor of 2

Question 7

glandular dose is most concerning-

Answer 7

limit screening exams to 2 views

Question 8

extremity exams-

Answer 8

-routine exams, but not a major concern
-techniques are relatively low
-reduce risk of skin exposure
-most extremity exams are of joints & not of long bones (bone marrow exposure is low)
-no gonadal exposure (GSD not affected).

Question 9

reduce unnecessary patient dose by (5)-

Answer 9

-reducing unnecessary exams
-reducing repeat exams
-technique
-IR
-positioning

Question 10

reducing unnecessary exams (6)-

Answer 10

-mass screening for TB
-hospital admissions
-pre-employment physicals
-periodic health examinations
-emergency room CT
-whole-body multislice helical CT screening

Question 11

technique-

Answer 11

always use high kVp & low mAs; no amt of kVp can compensate for insufficient mAs

Question 12

IR-

Answer 12

high speed IR require more patient dose

Question 13

positioning-

Answer 13

position the whole patient & not just the part

Question 14

specific area shielding-

Answer 14

primarily gonadal

Question 15

practices to reduce patient dose (4)-

Answer 15

-use high kVp/low mAs techniques- 150 is max kVp
-use appropriate IR
-position patient to avoid gonadal exposure
-use lead shielding

Question 16

general rule of radiobiology-

Answer 16

the higher the dose the more likely a severe response

Question 17

most critical time for a pregnant patient-

Answer 17

first 2 weeks

Question 18

radiobiology of a pregnant patient in the first 2 weeks-

Answer 18

-Pt. may not know she’s pregnant
-Most likely response is spontaneous abortion, reabsorption of fetus

Question 19

2nd-10th week of pregnant patient aka-

Answer 19

period of major organogenesis

Question 20

associated w: period of major organogenesis-

Answer 20

congenital abnormalities

Question 21

irradiation in 2nd & 3rd trimester-

Answer 21

will most likely result in malignant disease in early childhood

Question 22

major administration concern in a pregnant patient-

Answer 22

safeguard against accidental irradiation

Question 23

technical factor most appropriate for imaging a pregnant patient-

Answer 23

high kVp

Question 24

elective booking-

Answer 24

requires radiologist or technician to determine the time of the patients previous menstrual cycle

Question 25

10 day rule-

Answer 25

women of childbearing age receives x-rays of abdomen or pelvis only during first 10 days after start of menstrual cycle when it’s reasonably certain they can’t be pregnant