Ch 37 Patient dose Flashcards Preview

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Flashcards in Ch 37 Patient dose Deck (40)
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1
Q

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

A

18%

2
Q

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

A

Phantoms

3
Q

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

A
  1. Entrance Skin Exposure
  2. Bone Marrow Dose
  3. Gonadal Dose
4
Q

What is Entrance Skin Exposure?

A
  • Most common way to report dose

- Easy to measure directly

5
Q

What is Bone Marrow Dose?

A
  • Target area for Leukemia
  • Cannot be measured directly
  • Calculated from ESE
6
Q

What is Gonadal Dose?

A
  • Target for genetic effects

- Easy to measure or estimate

7
Q

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

A

Patient Dose

8
Q

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

A

Up to 3 months

9
Q

TLD’s are highly ______ and compact.

A

Sensitive

10
Q

_____ use a Lithium Fluoride sensing agent

A

TLD’s

11
Q

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

A

TLD’s

12
Q

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

A

Twice

13
Q

TLD’s can measure as low as ____ millirem.

A

1

14
Q

What are the disadvantages of TLD’s?

A
  • Higher cost
  • Can only be read once and then reused
  • Previous records are erased
  • No permanent record of exposure
15
Q

What are examples of some unnecessary exams?

A
  • Mass screening for tuberculosis
  • Hospital admission
  • Preemployment physicals
  • Periodic health examinations
  • ER CT
  • Repeat exams
  • Technique and positioning
16
Q

What are the exams with the highest repeat rates?

A
  • L-spine
  • T-spine
  • Chest and Abdomen
17
Q

What is the major cause for repeats?

A

Technologist error

18
Q

Repeat rate should not exceed ___%

A

5%

19
Q

Frequency of repeats may range as high as ___%

A

10%

20
Q

What are some examples of high dose examinations?

A
  • CT with an x-ray procedure
  • Helical CT- using multi slice
  • Fluoroscopy
  • C arm in surgery
21
Q

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

A

70%

22
Q

Proper ________ is essential, especially with pregnant patients.

A

Collimation

23
Q

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

A

Higher

24
Q

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

A

Reduce

25
Q

When is Major Organogenesis?

A

2nd- 10th week of pregnancy

26
Q

The higher the dose the more _____ the radiation response.

A

Severe

27
Q

What is major organogenesis?

A

The major organ systems of the fetus developing

28
Q

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

A

Resorption

29
Q

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

A

The first two weeks

30
Q

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

A

Skeletal deformities

31
Q

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

A

Neurologic deficiencies

32
Q

___% of all live births exhibit a manifest congenital abnormality

A

5%

33
Q

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

A

25-50%

34
Q

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

A

10 rad

35
Q

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

A
  1. Elective Booking
  2. Patient Questionnaire
  3. Posting
36
Q

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

A

Greater than 25 rads

37
Q

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

A

25 rad

38
Q

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

A

There is none

39
Q

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

A

40 mGy/ min

40
Q

Glandular dose is approximately ___% of ESE.

A

15%