Radiation oncology

Question 1

what are the top 3 cancer cases for men in the US?

Answer 1

1. prostate
2. lung
3. colon and rectum

Question 2

what are the top 3 cancer cases for women in the US?

Answer 2

1. breast
2. lung
3. colon and rectum

Question 3

what are the top 3 cancer deaths for men in the US?

Answer 3

1. lung
2. prostate
3. colorectal

Question 4

what are the top 3 cancer deaths for women in the US?

Answer 4

1. lung
2. breast
3. colorectal

Question 5

what is the staging for lymph node mets?

Answer 5

N

Question 6

what is the staging for hematogenous mets?

Answer 6

M

Question 7

what is the staging for adjacent organ tumor invasion?

Answer 7

T3-4

Question 8

what is the role of radiation in tumor treatment?

Answer 8

to replace or complement surgery

Question 9

what particle is used for deep seated tumors?

Answer 9

photons (x rays)

Question 10

what particle is used for superficial tumors?

Answer 10

electrons

Question 11

definition: radiosensitive

Answer 11

tumor melts with RT - does not depend on kinetics

Question 12

definition: radioresponsive

Answer 12

tumor melts quickly

Question 13

what are classic examples of tumors that are both radiosensitive and radioresponsive?

Answer 13

lymphoma, small cell lung

Question 14

what is the main target for radiation therapy? what is the most important lesion produced?

Answer 14

1. DNA of well oxygenated tumors in M/G2 phase

2. double strand DNA break

Question 15

what is the radiosensitive phase of a tumor?

Answer 15

M/G2

Question 16

what is the radioresponsive phase of a tumor?

Answer 16

S

Question 17

what biological process is essential to radiation cell kill over time?

Answer 17

reoxygenation

Question 18

GTV

Answer 18

gross tumor volume - seen with naked eye

Question 19

CTV

Answer 19

1. margin on GTV to account for tissue with presumed tumor / typical site of disease spread
2. assumes no tumor cells outside this volume

Question 20

ITV

Answer 20

CTV plus internal margin for physiological movements / error

Question 21

PTV

Answer 21

CTV or ITV plus setup margin uncertainty / error

Question 22

what is IGRT?

Answer 22

a way to verify with greater precision the tumor’s position to allow for more accurate treatment

Question 23

what are the indications for IGRT?

Answer 23

1. tumors that move

2. tumors abutting critical structures such as spinal cord and brainstem

Question 24

what are the two types of IGRT?

Answer 24

1. stereoscopic / bony

2. cone beam / soft tissue

Question 25

what is stereoscopic / bony IGRT?

Answer 25

uses bone structure as template for alignment

Question 26

what is cone beam / soft tissue IGRT?

Answer 26

uses a same-day CT for fusion to simulation image