Question 1

Brachytherapy is a procedure that involves which of the following procedures?

Accepted Answer

A)  physical removal of tumour
B)  irradiation of the tumour with high energy electromagnetic waves
C)  insertion of radioisotopes directly into the tumour
D)  chemotherapyE) All of the above
F) A) and B)

Question 2

A tumour at a depth of 10 cm is treated with a radiation beam delivering 1.86 Gy. What is the percent depth dose function for the tumour if the maximal dose the patient received was 2.3 Gy?

Accepted Answer

A)  0.8%
B)  4%
C)  12%
D)  81%E) B) and C)
F) B) and D)

Question 3

What of these is the setup in the current design of a Co-60 unit, which is used to administer radiation in radiation therapy?

Accepted Answer

A)  The radiation source is placed in a spot called the isocentre, from which the radiation beam is aimed at the patient.
B)  The part of the patient's body where the tumour is located is placed in the isocentre, around which numerous sources of radiation are arrayed in a circle, administering radiation from various angles.
C)  The part of the patient's body where the tumour is located is placed in the isocentre.The treatment head with a single source of radiation rotates around the isocentre, administering radiation from various angles.
D)  The radiation source is placed in a spot called the isocentre, from which the treatment head goes back and forth toward the patient, administering radiation from various angles.E) None of the above
F) All of the above

Question 4

The isocentre in a Co-60 anti-cancer treatment unit is the place where the tumour is placed and the treatment head rotates around it, delivering beams from various angles.

Accepted Answer

A) True 
 B)False

Question 5

Describe the role of radiotherapy in treating a brain tumour.

Accepted Answer

After surgical removal of the tumour, po...

Question 6

Malignant cells are more resistant to radiation than normal cells.

Accepted Answer

A) True 
 B)False

Question 7

How many cancer cells will survive this dose of radiation? Radiation is administered in a dose of 2 Gy. For palpable human cancer, take the initial number of cells to be 109, and constants á = 0.15 Gy-1 and â = 0.025 Gy-2.

Accepted Answer

6.7 × 10⁸
R...

Question 8

Standard geometry of beams in radiotherapy consists of opposing beams that are parallel.

Accepted Answer

A) True 
 B)False

Question 9

What is the order of magnitude of energy electron gains in a medical linear accelerator that is accelerated to 99% of the speed of light?

Accepted Answer

A)  eV
B)  keV
C)  MeV
D)  GeVE) None of the above
F) C) and D)

Question 10

Which one of the following factors is NOT relevant to the percent depth dose function?

Accepted Answer

A)  beam size
B)  beam energy
C)  phantom depth
D)  tissue to air ratioE) B) and C)
F) A) and C)

Question 11

Briefly describe the linear-quadratic model.

Accepted Answer

The linear-quadratic (LQ) model is used ...

Question 12

Briefly explain the procedure and benefits of brachytherapy.

Accepted Answer

Brachytherapy (from the Greek brachys me...

Question 13

Explain the process of shrinking of the tumour, in time, due to exposure to radiation therapy. How does the average human tumour react to radiation therapy? What model is used to predict the surviving fraction of cells?

Accepted Answer

A tumour shrinks the most during the fir...

Question 14

What is the penumbra effect of a Co-60 medical device, what is it good for, and what are its disadvantages?

Accepted Answer

The edge of the beam has a gradient; the radiation field edges are fuzzy. That is useful for large tumours with poorly defined edges. It is NOT useful for small well-defined tumours where healthy tissue receives unnecessary radiation.
RAT: The edge of the beam has a gradient; the radiation field edges are fuzzy. That is useful for large tumours with poorly defined edges. It is NOT useful for small well-defined tumours where healthy tissue receives unnecessary radiation.

Question 15

In a medical linear accelerator, electrons are accelerated using the electric field component of electromagnetic waves from the microwave region.

Accepted Answer

A) True 
 B)False

Question 16

Briefly explain the advantage of using the tissue air ratio (TAR) function rather than the percent depth dose (PDD) function as a parameter of a radiation beam administered in radiation therapy of a tumour.

Accepted Answer

In the current design of an isocentric Co-60 unit, the treatment head rotates around the patient, administering the radiation beam from various angles. The percent depth dose (PDD) function depends on the position of the treatment head with respect to the tissue, but the tissue air ratio (TAR) function depends only on the distance, and in an isometric setup, the distance of the rotating head from the tumour is always the same.
RAT: In the current design of an isocentric Co-60 unit, the treatment head rotates around the patient, administering the radiation beam from various angles. The percent depth dose (PDD) function depends on the position of the treatment head with respect to the tissue, but the tissue air ratio (TAR) function depends only on the distance, and in an isometric setup, the distance of the rotating head from the tumour is always the same.

Question 17

Percent depth dose tells us about the radiation deposited along both the central beam axis and the off axis.

Accepted Answer

A) True 
 B)False  False

Question 18

To test radiation transport through human tissue, a container of water is used as a simulation of actual human tissue.

Accepted Answer

A) True 
 B)False

Question 19

A tumour is treated with a Co-60 unit. TAR for the position and the field is determined to be 0.80. What is the administered dose of radiation if the treatment lasts 92 seconds? The machine's in-air dose rate at the isocentre is 1.50 Gy/min.

Accepted Answer

A)  1.8 Gy
B)  2.9 Gy
C)  49 Gy
D)  1.1 × 102 GyE) None of the above
F) B) and D)

Question 20

Only X-rays and gamma rays are used in radiation therapy.

Accepted Answer

A) True 
 B)False

Exam 27: Radiation Therapy

Brachytherapy is a procedure that involves which of the following procedures?

Correct Answer
verified

A tumour at a depth of 10 cm is treated with a radiation beam delivering 1.86 Gy. What is the percent depth dose function for the tumour if the maximal dose the patient received was 2.3 Gy?

Correct Answer
verified

What of these is the setup in the current design of a Co-60 unit, which is used to administer radiation in radiation therapy?

Correct Answer
verified

The isocentre in a Co-60 anti-cancer treatment unit is the place where the tumour is placed and the treatment head rotates around it, delivering beams from various angles.

Correct Answer
verified

Describe the role of radiotherapy in treating a brain tumour.

Correct Answer
verified
After surgical removal of the tumour, po...
View Answer

Malignant cells are more resistant to radiation than normal cells.

Correct Answer
verified

How many cancer cells will survive this dose of radiation? Radiation is administered in a dose of 2 Gy. For palpable human cancer, take the initial number of cells to be 10⁹, and constants á = 0.15 Gy^-1 and â = 0.025 Gy^-2.

Correct Answer
verified
6.7 × 10⁸
R...
View Answer

Standard geometry of beams in radiotherapy consists of opposing beams that are parallel.

Correct Answer
verified

What is the order of magnitude of energy electron gains in a medical linear accelerator that is accelerated to 99% of the speed of light?

Correct Answer
verified

Which one of the following factors is NOT relevant to the percent depth dose function?

Correct Answer
verified

Briefly describe the linear-quadratic model.

Correct Answer
verified
The linear-quadratic (LQ) model is used ...
View Answer

Briefly explain the procedure and benefits of brachytherapy.

Correct Answer
verified
Brachytherapy (from the Greek brachys me...
View Answer

Explain the process of shrinking of the tumour, in time, due to exposure to radiation therapy. How does the average human tumour react to radiation therapy? What model is used to predict the surviving fraction of cells?

Correct Answer
verified
A tumour shrinks the most during the fir...
View Answer

What is the penumbra effect of a Co-60 medical device, what is it good for, and what are its disadvantages?

In a medical linear accelerator, electrons are accelerated using the electric field component of electromagnetic waves from the microwave region.

Correct Answer
verified

Briefly explain the advantage of using the tissue air ratio (TAR) function rather than the percent depth dose (PDD) function as a parameter of a radiation beam administered in radiation therapy of a tumour.

Percent depth dose tells us about the radiation deposited along both the central beam axis and the off axis.

Correct Answer
verified
False

To test radiation transport through human tissue, a container of water is used as a simulation of actual human tissue.

Correct Answer
verified

A tumour is treated with a Co-60 unit. TAR for the position and the field is determined to be 0.80. What is the administered dose of radiation if the treatment lasts 92 seconds? The machine's in-air dose rate at the isocentre is 1.50 Gy/min.

Correct Answer
verified

Only X-rays and gamma rays are used in radiation therapy.

Correct Answer
verified

Exam 27: Radiation Therapy

Brachytherapy is a procedure that involves which of the following procedures?

Correct AnswerverifiedShow Answer

A tumour at a depth of 10 cm is treated with a radiation beam delivering 1.86 Gy. What is the percent depth dose function for the tumour if the maximal dose the patient received was 2.3 Gy?

Correct AnswerverifiedShow Answer

What of these is the setup in the current design of a Co-60 unit, which is used to administer radiation in radiation therapy?

Correct AnswerverifiedShow Answer

The isocentre in a Co-60 anti-cancer treatment unit is the place where the tumour is placed and the treatment head rotates around it, delivering beams from various angles.

Correct AnswerverifiedShow Answer

Describe the role of radiotherapy in treating a brain tumour.

Correct AnswerverifiedAfter surgical removal of the tumour, po...View AnswerShow Answer

Malignant cells are more resistant to radiation than normal cells.

Correct AnswerverifiedShow Answer

How many cancer cells will survive this dose of radiation? Radiation is administered in a dose of 2 Gy. For palpable human cancer, take the initial number of cells to be 109, and constants á = 0.15 Gy-1 and â = 0.025 Gy-2.

Correct Answerverified6.7 × 108R...View AnswerShow Answer

Standard geometry of beams in radiotherapy consists of opposing beams that are parallel.

Correct AnswerverifiedShow Answer

What is the order of magnitude of energy electron gains in a medical linear accelerator that is accelerated to 99% of the speed of light?

Correct AnswerverifiedShow Answer

Which one of the following factors is NOT relevant to the percent depth dose function?

Correct AnswerverifiedShow Answer

Briefly describe the linear-quadratic model.

Correct AnswerverifiedThe linear-quadratic (LQ) model is used ...View AnswerShow Answer

Briefly explain the procedure and benefits of brachytherapy.

Correct AnswerverifiedBrachytherapy (from the Greek brachys me...View AnswerShow Answer

Explain the process of shrinking of the tumour, in time, due to exposure to radiation therapy. How does the average human tumour react to radiation therapy? What model is used to predict the surviving fraction of cells?

Correct AnswerverifiedA tumour shrinks the most during the fir...View AnswerShow Answer

What is the penumbra effect of a Co-60 medical device, what is it good for, and what are its disadvantages?

In a medical linear accelerator, electrons are accelerated using the electric field component of electromagnetic waves from the microwave region.

Correct AnswerverifiedShow Answer

Briefly explain the advantage of using the tissue air ratio (TAR) function rather than the percent depth dose (PDD) function as a parameter of a radiation beam administered in radiation therapy of a tumour.

Percent depth dose tells us about the radiation deposited along both the central beam axis and the off axis.

Correct AnswerverifiedFalse

To test radiation transport through human tissue, a container of water is used as a simulation of actual human tissue.

Correct AnswerverifiedShow Answer

A tumour is treated with a Co-60 unit. TAR for the position and the field is determined to be 0.80. What is the administered dose of radiation if the treatment lasts 92 seconds? The machine's in-air dose rate at the isocentre is 1.50 Gy/min.

Correct AnswerverifiedShow Answer

Only X-rays and gamma rays are used in radiation therapy.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
After surgical removal of the tumour, po...
View Answer

Correct Answer
verified

How many cancer cells will survive this dose of radiation? Radiation is administered in a dose of 2 Gy. For palpable human cancer, take the initial number of cells to be 10⁹, and constants á = 0.15 Gy^-1 and â = 0.025 Gy^-2.

Correct Answer
verified
6.7 × 10⁸
R...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The linear-quadratic (LQ) model is used ...
View Answer

Correct Answer
verified
Brachytherapy (from the Greek brachys me...
View Answer

Correct Answer
verified
A tumour shrinks the most during the fir...
View Answer

Correct Answer
verified

Correct Answer
verified
False

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified