Imaging Safety

Question 1

contraindications to contrast?

Answer 1

renal function eg eGFR <30

contrast allergy

Question 2

imaging is not usually done for __ week post-op patients

Answer 2

<6

Question 3

contraindications to MRI?

Answer 3

pacemaker

some metallic implants

Question 4

what areas of the body are most susceptible to radiation damage? what happens to them?

Answer 4

lens of eye -> cataracts
skin -> erythema
bone marrow -> dec production
gonads -> infertility

Question 5

what layer of skin is most susceptible to radiation damage?

Answer 5

stratum corneum

Question 6

what emits more radiation: CXR or lumbar spine XR

Answer 6

lumbar spine XR

emits about 1mSV whereas CXR emits 0.02msV

Question 7

what cells have to be affected for someone’s child to develop radiation-related developmental issues?

Answer 7

germline cells

Question 8

name some long term somatic effects of radiation

Answer 8

cancer
cerebrovascular disease
cardiovascular disease

Question 9

give an example of a stochastic effect of radiation

Answer 9

cancer
hereditary abnormalities

these do not have a set threshold at which they would occur, they just involve chance

Question 10

give an example of a deterministic effect of radiation

Answer 10

erythema
cataracts
hair loss

these are guaranteed to occur above a certain threshold

Question 11

the severity of a stochastic radiation effect increases with dose T/F

Answer 11

F

is unrelated to dose, it could happen at a low dose or a high dose

Question 12

what imaging option has the most radiation exposure?

Answer 12

abdo CT (10msv)

Question 13

how much radiation are we exposed to from our environment?

Answer 13

2msv

Question 14

what kind of imaging exposes you to the same amount of radiation you would accumulate in a year?

Answer 14

head CT (2msv)

Question 15

a barium enema emits more radiation than a lumbar spine XR T or F

Answer 15

T

BE emits about 3-8msv whereas a lumbar spine XR emits 0.7msv

Question 16

what are the risks of radiation exposure early in pregnancy?

Answer 16

tissue abnormalities
slowed mental development
death
childhood cancer

Question 17

which radiation risk during pregnancy is the most common?

Answer 17

fetal death

Question 18

what fetal tissues are most at risk of malformation from radiation? why?

Answer 18

brain
CNS

these cells are highly undifferentiated

Question 19

most neural development occurs between _ and - weeks

Answer 19

8 and 15

Question 20

iodine based Tx or Ix can cause abnormalities where in the fetus?

Answer 20

thyroid

Question 21

what advice should be given to a woman of childbearing age who is to receive radionucleotide Tx?

Answer 21

avoid conception for several months

Question 22

radioactivity can be secreted in breast milk T/F

Answer 22

T

Question 23

a woman should stop breastfeeding altogether if she is on radionucleotides T/F

Answer 23

F

depends on the radionucleotide strength

Question 24

During the first __ days of the menstrual cycle it is thought that there is no significant risk of any radiation effect in a foetus that is conceived subsequently

Answer 24

10

if radiation exposure occurs before ovulation the fetus should be unaffected

Question 25

An absorbed dose to the foetus of >__ mGy after the first few weeks of pregnancy could double the natural incidence of childhood cancer

Answer 25

10 (this is very unlikely though)