Deck 15: Aspects of Brachytherapy

Question 1

Of the following,which brachytherapy would be used to treat the breast?

A) intracavitary
B) interstitial
C) topical
D) permanent implant

Answer 1

B
Interstitial brachytherapy is commonly used in the treatment of neck,breast,prostate,soft tissue sarcomas,and skin tumors.

Question 2

Which of the following is an advantage of HDR over LDR?

A) HDR is noninvasive.
B) HDR dosimetry is simpler.
C) Treatment time is decreased from 72 hours to 24 hours.
D) HDR can be given on an outpatient basis.

Answer 2

D
It is suggested that HDR brachytherapy may be preferable to the LDR treatment because HDR can be given on a fractionated outpatient basis.

Question 3

Which of the following has the shortest half-life?

A) gold 198 - 2.7 days
B) iodine 125 - 59.4 days
C) cesium 137 - 30 years
D) cobalt 60 - 5.27 years

Answer 3

A
Gold 198 has a very short half-life of 2.7 days.Iodine 125 has a half-life of 59.4 days.Cesium 137 has a half-life of 30.0 years,so sources can be used for a long time.Cobalt 60 has a half-life of 5.27 years.

Question 4

Brachytherapy involves placing radioactive material directly into or adjacent to the tumor.

Question 5

Decay constant is expressed as:

A) time it takes for activity to decay to half its original value
B) total number of atoms that decay per unit time
C) average lifetime for the decay of radioactive atoms
D) total number of atoms that decay

Question 6

The use of iodine 125 is becoming more frequent in intracavitary implants.

Question 7

Of the following,which radionuclide is used for permanent prostate implants?

A) gold 198
B) cobalt 60
C) cesium 137
D) iridium 192

Question 8

Which of the following is true regarding the Quimby system?

A) It is used more often than the Paterson-Parker system.
B) It is adapted into system called the Manchester system.
C) There is a uniform distribution of activity within the implant.
D) The result is a uniform dose distribution.

Question 9

HDR is more expensive than LDR.

Question 10

What is the purpose of dummy sources used for temporary implants?

A) to localize the tumor in surgery
B) to enable visualization of source placement
C) to give physics residents experience with loading sources
D) to determine dose to the bladder and rectum

Question 11

What is the half-life of gold 198?

A) 27 days
B) 27 years
C) 2.7 days
D) 3.8 days

Question 12

One disadvantage of radium is:

A) It has a long half-life.
B) It decays by alpha emission.
C) It is not as effective as other radioisotopes.
D) It decays to form a radon,a dangerous gas.

Question 13

Areas commonly treated with external applicators include: I.hard palate
II)skin
III)orbital cavity

A) I and II
B) I and III
C) II and III
D) I,II,and III

Question 14

For brachytherapy to the cervix,where is point A located in relation to the cervical os?

A) 2 cm superior and 2 cm lateral
B) 1 cm superior and 2 cm lateral
C) 2 cm inferior and 2 cm lateral
D) 2 cm superior and 1 cm lateral

Question 15

What is an advantage of remote afterloading?

A) less invasive for the patient
B) limits exposure to the patient and personnel
C) decreased treatment time
D) allows the patient to have a semiprivate room

Question 16

Tandem and ovoids are used to treat which of the following?

A) prostate
B) bladder
C) cervix
D) esophagus

Question 17

Cesium 137 is used for the treatment of prostate cancer.

Question 18

The Paterson-Parker (Manchester)system uses a set of guidelines to: I.provide a dose of +10% within the implanted area
II)assume the use of linear sources to be implanted
III)use a uniform distribution of radioactive material to produce a uniform dose distribution

A) I and II
B) I and III
C) II and III
D) I,II,and III

Question 19

The half-life of radium is:

A) 1.6 years
B) 162 days
C) 1,622 years
D) 16 years

Question 20

The purpose of intravascular brachytherapy is to:

A) eliminate arterial plaque
B) treat cancers of the heart
C) prevent heart disease
D) inhibit restenosis in coronary arteries

Question 21

Regarding question 20,why is brachytherapy the treatment of choice?

A) It has a high energy.
B) It is more effective than stereotactic and proton therapy procedures.
C) Vision is spared due to lack of radiation-induced changes .
D) It is less expensive for the patient.

Question 22

Which of the following brachytherapy sources is used to treat breast cancer?

A) gold-198
B) iodine 125
C) iridium 192
D) radium 226

Question 23

Permanent implants involve: I.sources packaged as tiny seeds
II)sources with long half-lives
III)sources implanted with needles in surgery
IV)tumors that cannot be reached surgically

A) I and II
B) I and III
C) II and III
D) I,II,and III

Question 24

Which of the following is true regarding cobalt 60?

A) It is a common radionuclide used in brachytherapy.
B) It has a half-life of 5.27 years .
C) Its energy is 3.25 MeV.
D) It was not effective as an external beam source.

Question 25

An autoradiograph is taken to:

A) determine the energy of the source
B) check source placement in the patient
C) verify uniformity of source
D) determine source strength

Question 26

The term radium substitute in brachytherapy indicates:

A) an isotope whose dosimetry is based on original radium work
B) an isotope whose dosimetry is more accurate than that of radium
C) any source implemented when radium is unavailable
D) a source that has a greater average energy than radium

Question 27

The shape of the isodose distribution for a tandem and ovoid treatment is:

A) apple shaped
B) triangular
C) mushroom shaped
D) pear shaped

Question 28

The radioisotope used to treat uveal melanoma of the eye is:

A) iridium 192
B) cesium 137
C) gold 198
D) iodine 125

Question 29

What is the average energy of iridium 192?

A) 170 keV
B) 730 keV
C) 450 keV
D) 380 keV

Question 30

The Paris system is based on which of the following?

A) Radioactive sources must be rectilinear.
B) Source centers must be in a different plane.
C) Linear activity must be nonuniform along each source.
D) Sources can be spaced at any distance.