Ch 8

Question 1

Thermoluminescence refers to emission of:
A. High intensity light from electron beams
B. High intensity light from photon beams
C. Light from certain materials when heated
D. Light from thermonuclear reaction

Answer 1

C. Light from certain materials when heated

Question 2

The light signal produced from thermoluminescence dosimetry is amplified by:
A. An electrometer
B. A densitometer
C. A photomultiplier tube
D. A calorimeter

Answer 2

C. A photomultiplier tube

Question 3

The most commonly used thermoluminescence material used in radiation dosimetry is:
A. Ca So4
B. Ca F2
C. Li F
D. Li2 B

Answer 3

C. Li F

Question 4

For megavoltage dosimetry, thermoluminescence dosimetry can provide accuracy of:
A. ± 20%
B. ± 10%
C. ± 3%
D. ± 1%

Answer 4

C. ± 3%

Question 5

A radiographic film consists of:
A. Acrylic coated with toner
B. Cellulose acetate coated with an emulsion containing silver bromide
C. Acrylic coated with cellulose acetate
D. Cellulose acetate coated with polystyrene

Answer 5

B. Cellulose acetate coated with an emulsion containing silver bromide

Question 6

During the development of the film:
A. Silver is added to the film
B. Silver is removed from the film
C. Silver bromide affected by radiation is reduced to small crystals of silver
D. None of the above

Answer 6

C. Silver bromide affected by radiation is reduced to small crystals of silver

Question 7

During the fixing of the developed film, the:
A. Unaffected granules of silver bromide are fixed in the film
B. Unaffected granules of silver bromide are removed from the film
C. Affected granules are removed
D. Affected granules are fixed

Answer 7

B. Unaffected granules of silver bromide are removed from the film

Question 8

If Io and It are incident and transmitted light intensities, respectively, the optical
density is defined as:
A. Io / It
B. 100 x Io / It
C. Log (Io / It)
D. Log (Io - It

Answer 8

C. Log (Io / It)

Question 9

The H-D curve for a type of film is a plot of:
A. Incident vs. transmitted light intensities
B. The optical density vs. exposure
C. Net light intensity vs. transmitted light intensity
D. Net light intensity vs. incident light intensity

Answer 9

B. The optical density vs. exposure

Question 10

Film Dosimetry is extremely useful for:
A. Absolute dosimetry
B. Relative dosimetry
C. In-vivo dosimetry
D. Radiobiological dosimetry

Answer 10

B. Relative dosimetry

Question 11

With megavoltage film dosimetry, isodose curves can be measured to within
A. ± 10%
B. ± 7%
C. ± 3%
D. ± 1%

Answer 11

C. ± 3%

Question 12

Film badges for personnel dosimetry have a reliability of:
A. ± 50%
B. ± 30%
C. ± 10%
D. ± 1%

Answer 12

C. ± 10%

Question 13

Radiochromic films are best suited for measurements of:
A. Low dose radiation (less than 1 millirad)
B. High dose levels (10Gy-10^4 Gy)
C. Temperature
D. None of the above

Answer 13

B. High dose levels (10Gy-10^4 Gy)

Question 14

Radiochromic film requires:
A. Extensive processing
B. Immediate processing
C. No processing
D. Low temperature storage

Answer 14

C. No processing

Question 15

Measurements on a radiochromic film are made with:
A. An electrometer
B. Spectrometer or densitometer
C. Magnetometer
D. None of the above

Answer 15

B. Spectrometer or densitometer

Question 16

The response of radiochromic films is:
A. Independent of pressure
B. Dependent on room temperature
C. Dependent on room light intensity
D. Independent of all of the above

Answer 16

B. Dependent on room temperature

Question 17

The reproducibility of radiation measurements with radiochromic film is about:
A. ± 1%
B. ± 5%
C. ± 7%
D. ± 10%

Answer 17

B. ± 5%

Question 18

For use in the clinical range of photon and electron therapy beams, the response of radiochromic
film is:
A. Independent of energy
B. Slightly energy-dependent
C. Very dependent
D. None of the above
E. ± 1%

Answer 18

B. Slightly energy-dependent

Question 19

A diode dosimeter is:
A. An ionization chamber coated with silicon
B. A vacuum tube
C. A solid state device
D. Baldwin Farmer chamber

Answer 19

C. A solid state device

Question 20

In megavoltage therapy, diodes are well suited for:
A. Absolute dosimetry
B. Relative dosimetry
C. Thermometry
D. Imaging

Answer 20

B. Relative dosimetry

Question 21

In megavoltage therapy, typical use(s) of diodes is for:
A. Patient dosimetry
B. Beam scanning
C. Quality assurance
D. All of the above

Answer 21

D. All of the above

Question 22

Which of the following is best suited for calibration of a megavoltage beam:
A. Diode detector
B. Thermoluminescence dosimetery
C. Film
D. Ionization chamber

Answer 22

D. Ionization chamber

Question 23

Acceptance testing of a radiation therapy machine relates to:
A. Developing a better design of its components
B. Comparing the specifications in the purchase order to the measured performance of the machine
C. Adjusting the electrical and mechanical parameters of the machine
D. Measuring the performance of subsystems

Answer 23

B. Comparing the specifications in the purchase order to the measured performance of the machine

Question 24

The commissioning of a therapy machine requires:
A. Measuring equipment
B. Acquisition of clinical data
C. Calibration of all the physical and radiation parameters
D. All of the above

Answer 24

D. All of the above

Question 25

Calibration of a machine primarily deals with:
A. Radiation beam parameters
B. Mechanical parameters
C. Digital displays
D. Laser equipment
E. All of the above

Answer 25

E. All of the above

Question 26

A good standard of practice requires that a treatment machine should undergo a
complete calibration at least:
A. Before any treatment
B. Daily
C. Weekly
D. Monthly
E. Annually

Answer 26

E. Annually

Question 27

A consistency check of radiation beams should be performed at least:
A. Daily
B. Weekly
C. Monthly
D. Annually

Answer 27

B. Weekly