Patient Radiation Dose Management

Question 1

Exposure to medical radiation is up by ___ in the U.S.

Answer 1

18%

Question 2

Patient dose is usually estimated by

Answer 2

conducting simulated x-ray exams with human phantoms and test objects.

Question 3

Patient dose from diagnostic x-rays can be reported in three ways

Answer 3

Exposure, Bone Marrow Dose and Gonadal dose

Question 4

Bone Marrow is important because

Answer 4

it can indicate radiation-induced leukemia Bone.

calculated from ESE

Question 5

Marrow dose is estimated by

Answer 5

Entrance Skin Exposure.

Question 6

Entrance skin exposure

Answer 6

Most common way to report dose, easy to measure directly

Question 7

Gonadal dose

Answer 7

target for genetic effects, easy to measure or estimate

Question 8

Entrance Skin dose most often referred to as _____

Answer 8

“patient dose”

Question 9

Entrance Skin dose(ESD)

Answer 9

• Easily measured with or without measurement devices
• Entrance Skin Dose is used to estimate Bone Marrow Does
• Efficiency of the radiology equipment will change these doses from facility to facility.

Question 10

Thermoluminescence Dosimetry

Answer 10

• Like the film badge can be worn up to 3 mos.
• Must be processed – can measure as low as 1 millirem.
• Highly sensitive , compact
• Most accurate and not affected by humidy.
• Twice the price of a film badge.

Question 11

Thermoluminescence Dosimetry uses

Answer 11

lithium fluoride (LiF)

Question 12

what monitor is most frequently used to measure pt. exposure?

Answer 12

Thermoluminescence Dosimetry

Question 13

disadvantage of Thermoluminescence Dosimetry (TLD)

Answer 13

1. Higher cost
2. Can only be read once and then reused
3. Previous records are erased – therefore no permanent or legal record of exposure

Question 14

We can Reduce Unnecessary Patient Dose by unnecessary exams of what kind?

Answer 14

-mass screening of TB
-hospital admission
-preemployment physicals
-periodic health exams
-emergency room CT
-Whole body multislice spiral CT screening
-

Question 15

Reducing Unnecessary Patient Dose

Answer 15

unnecessary exams, repeat exams, technique and positioning

Question 16

Frequency of repeats may range as high as __

Answer 16

10%

Question 17

Repeat rate should NOT exceed ___

Answer 17

5%

Question 18

major cause for repeats

Answer 18

Technologist error

Question 19

Exams with high repeat rates:

Answer 19

• L – spine
• T – spine
• Abdomen

Question 20

High Dose Examinations

Answer 20

• CT with an x-ray procedure.
• Helical CT – using multislice
• Fluoroscopy
• C – arm in surgery

Question 21

CT accounts for ___ of the total patient effective dose

Answer 21

70%

Question 22

Practices to reduce dose to patients: High kVp technique results in _______

Answer 22

reduced pt. dose

Question 23

Practices to reduce dose to patients: Digital radiography can be conducted at higher kVp, resulting in ______

Answer 23

lower pt. dose

Question 24

Practices to reduce dose to patients: Proper collimation is essential especially with________

Answer 24

pregnant patients.

Question 25

____ screen-film combination should be used to reduce patient dose

Answer 25

Fast

Question 26

What is most sensitive in early pregnancy?

Answer 26

Fetus

Question 27

Pregnancy: Higher the dose the ______ will be the radiation response

Answer 27

more severe

Question 28

Radiation & Pregnancy is ______& ____ dependence

Answer 28

time and dose

Question 29

Major Organogenesis occur during

Answer 29

2nd – 10th week of pregnancy

Question 30

First two weeks of pregnancy

Answer 30

- high exposure may cause resorption of the embryo - no other response likely - no possibility of the induction of congenital abnormalities

Question 31

Second week to 10th week

Answer 31

- major Organogenesis - major organ systems of the fetus developing - high exposure may cause congenitial abnormalities

Question 32

___ of all live births exhibit a manifest congenital abnormality.

Answer 32

5%

Question 33

___ increase there after the exposure of radiation (10 rad).

Answer 33

1%

Question 34

Spontaneous abortion in the absence of radiation – ____

Answer 34

25% – 50%

Question 35

Protocol for patient safety

Answer 35

1. Elective Booking 2. Patient Questionnaire 3. Posting

Question 36

A dose >25 rads (250 mGy) must be acquired to see an increase of risk factors such as:

Answer 36

- Congenital abnormalities (skeletal deformities) | - Neurologic deficiencies

Question 37

NCRP recommendations:

Answer 37

- No recommendations for abortion after diagnostic x-ray exposure. - Manifest damage to the new born is unlikely at fetal doses below 25 rad.

Question 38

Safeguard against the irradiation of unsuspected pregnancy

Answer 38

elective booking

Question 39

For average fluoro exam, one can assume an ESD of ____

Answer 39

40 mGyt/min

Question 40

The higher the multislice value, the __________

Answer 40

lower the patient dose will be