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RTCA241 Radiobiology > Patient Radiation Dose Management > Flashcards

Patient Radiation Dose Management Flashcards

1
Q

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

A

18%

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2
Q

Patient dose is usually estimated by

A

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

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3
Q

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

A

Exposure, Bone Marrow Dose and Gonadal dose

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4
Q

Bone Marrow is important because

A

it can indicate radiation-induced leukemia Bone.

calculated from ESE

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5
Q

Marrow dose is estimated by

A

Entrance Skin Exposure.

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6
Q

Entrance skin exposure

A

Most common way to report dose, easy to measure directly

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7
Q

Gonadal dose

A

target for genetic effects, easy to measure or estimate

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8
Q

Entrance Skin dose most often referred to as _____

A

“patient dose”

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9
Q

Entrance Skin dose(ESD)

A
  • 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.
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10
Q

Thermoluminescence Dosimetry

A
  • 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.
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11
Q

Thermoluminescence Dosimetry uses

A

lithium fluoride (LiF)

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12
Q

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

A

Thermoluminescence Dosimetry

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13
Q

disadvantage of Thermoluminescence Dosimetry (TLD)

A
  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
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14
Q

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

A

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

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15
Q

Reducing Unnecessary Patient Dose

A

unnecessary exams, repeat exams, technique and positioning

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16
Q

Frequency of repeats may range as high as __

A

10%

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17
Q

Repeat rate should NOT exceed ___

A

5%

18
Q

major cause for repeats

A

Technologist error

19
Q

Exams with high repeat rates:

A
  • L – spine
  • T – spine
  • Abdomen
20
Q

High Dose Examinations

A
  • CT with an x-ray procedure.
  • Helical CT – using multislice
  • Fluoroscopy
  • C – arm in surgery
21
Q

CT accounts for ___ of the total patient effective dose

A

70%

22
Q

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

A

reduced pt. dose

23
Q

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

A

lower pt. dose

24
Q

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

A

pregnant patients.

25
Q

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

A

Fast

26
Q

What is most sensitive in early pregnancy?

A

Fetus

27
Q

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

A

more severe

28
Q

Radiation & Pregnancy is ______& ____ dependence

A

time and dose

29
Q

Major Organogenesis occur during

A

2nd – 10th week of pregnancy

30
Q

First two weeks of pregnancy

A
  • high exposure may cause resorption of the embryo
  • no other response likely
  • no possibility of the induction of congenital abnormalities
31
Q

Second week to 10th week

A
  • major Organogenesis
  • major organ systems of the fetus developing
  • high exposure may cause congenitial abnormalities
32
Q

___ of all live births exhibit a manifest congenital abnormality.

A

5%

33
Q

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

A

1%

34
Q

Spontaneous abortion in the absence of radiation – ____

A

25% – 50%

35
Q

Protocol for patient safety

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

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

A
  • Congenital abnormalities (skeletal deformities)

- Neurologic deficiencies

37
Q

NCRP recommendations:

A
  • No recommendations for abortion after diagnostic x-ray exposure.
  • Manifest damage to the new born is unlikely at fetal doses below 25 rad.
38
Q

Safeguard against the irradiation of unsuspected pregnancy

A

elective booking

39
Q

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

A

40 mGyt/min

40
Q

The higher the multislice value, the __________

A

lower the patient dose will be

RTCA241 Radiobiology (3 decks)

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