Ch 37 Patient dose

Question 1

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

Answer 1

18%

Question 2

Patient dose is usually estimated by conducting simulated x-ray exams with human ________ and test objects.

Answer 2

Phantoms

Question 3

What are the (3) ways patient dose from diagnostic x-rays can be reported?

Answer 3

1. Entrance Skin Exposure
2. Bone Marrow Dose
3. Gonadal Dose

Question 4

What is Entrance Skin Exposure?

Answer 4

• Most common way to report dose

- Easy to measure directly

Question 5

What is Bone Marrow Dose?

Answer 5

• Target area for Leukemia
• Cannot be measured directly
• Calculated from ESE

Question 6

What is Gonadal Dose?

Answer 6

• Target for genetic effects

- Easy to measure or estimate

Question 7

What is ESD (Entrance Skin Dose) most often referred to as?

Answer 7

Patient Dose

Question 8

How long can a TLD (Thermoluminescence Dosimetry) be worn?

Answer 8

Up to 3 months

Question 9

TLD’s are highly ______ and compact.

Answer 9

Sensitive

Question 10

_____ use a Lithium Fluoride sensing agent

Answer 10

TLD’s

Question 11

What type of monitor is used to frequently measure patient exposure.

Answer 11

TLD’s

Question 12

TLD’s are ____ the price of a film badge.

Answer 12

Twice

Question 13

TLD’s can measure as low as ____ millirem.

Answer 13

1

Question 14

What are the disadvantages of TLD’s?

Answer 14

• Higher cost
• Can only be read once and then reused
• Previous records are erased
• No permanent record of exposure

Question 15

What are examples of some unnecessary exams?

Answer 15

• Mass screening for tuberculosis
• Hospital admission
• Preemployment physicals
• Periodic health examinations
• ER CT
• Repeat exams
• Technique and positioning

Question 16

What are the exams with the highest repeat rates?

Answer 16

• L-spine
• T-spine
• Chest and Abdomen

Question 17

What is the major cause for repeats?

Answer 17

Technologist error

Question 18

Repeat rate should not exceed ___%

Answer 18

5%

Question 19

Frequency of repeats may range as high as ___%

Answer 19

10%

Question 20

What are some examples of high dose examinations?

Answer 20

• CT with an x-ray procedure
• Helical CT- using multi slice
• Fluoroscopy
• C arm in surgery

Question 21

CT accounts for ___% of the total patient effective dose.

Answer 21

70%

Question 22

Proper ________ is essential, especially with pregnant patients.

Answer 22

Collimation

Question 23

Digital radiography can be conducted at ____ kVp, resulting in lower patient dose.

Answer 23

Higher

Question 24

Fast screen film combination should be used to ____ patient dose.

Answer 24

Reduce

Question 25

When is Major Organogenesis?

Answer 25

2nd- 10th week of pregnancy

Question 26

The higher the dose the more _____ the radiation response.

Answer 26

Severe

Question 27

What is major organogenesis?

Answer 27

The major organ systems of the fetus developing

Question 28

The most likely biologic response to irradiation during the first 2 weeks of pregnancy is ______ of the embryo, and therefore no pregnancy

Answer 28

Resorption

Question 29

What time during pregnancy is the least hazardous to receive irradiation?

Answer 29

The first two weeks

Question 30

Early in organogenesis if radiation dose is sufficiently high what is the most likely abnormality to occur?

Answer 30

Skeletal deformities

Question 31

Later in organogenesis if radiation dose is sufficiently high what type of abnormalities can occur?

Answer 31

Neurologic deficiencies

Question 32

___% of all live births exhibit a manifest congenital abnormality

Answer 32

5%

Question 33

What is the chance of a spontaneous abortion in the absence of radiation?

Answer 33

25-50%

Question 34

A 1% increase in congenital abnormalities happen after the exposure of a ___.

Answer 34

10 rad

Question 35

What is the protocol for patient safety to check for pregnancy?

Answer 35

1. Elective Booking 2. Patient Questionnaire 3. Posting

Question 36

What is the dose required to see an increase in risk factors such as congenital abnormalities and neurologic deficiencies?

Answer 36

Greater than 25 rads

Question 37

Manifest damage to the new born is unlikely at fetal doses below...

Answer 37

25 rad

Question 38

After a diagnostic x-ray exposure, what is the recommended dose before an abortion is recommended?

Answer 38

There is none

Question 39

For the average fluoroscopic exam, one can assume an ESE of ...

Answer 39

40 mGy/ min

Question 40

Glandular dose is approximately ___% of ESE.

Answer 40

15%