EXAM #2: RADIATION ONCOLOGY

Question 1

What is the most fatal cancer in the world?

Answer 1

Lung

Question 2

What are the three most common cancers in men?

Answer 2

Prostate
Lung and bronchus
Colon and rectum

Question 3

What are the three most common cancers in women?

Answer 3

Breast
Lung and bronchus
Colon and rectum

Question 4

What are the four basic patterns of cancer progression?

Answer 4

1) Local-growth
2) Local-extension i.e. tumor invades adjacent organs
3) Lymph node metastases
4) Hematogenous metastases

Question 5

What stage does local tumor growth determine?

Answer 5

T-stage

Question 6

What stage does local extension affect?

Answer 6

Upstaging the T-stage

Question 7

What stage does lymph node metastases affect?

Answer 7

N-stage

Question 8

What stage does hematogenous metastasis affect?

Answer 8

M-stage

Question 9

What cancers does radiation take the place of surgery in?

Answer 9

1) Anal
2) Limited stage small cell lung
3) Esophageal
4) Stage IIIB non-small cell lung cancer

Question 10

What cancers is radiation used as an adjuvant therapy in?

Answer 10

1) Breast
2) Skin with positive margins
3) Prostate
4) Uterine/ endometrial

Note that radiation is used AFTER the main surgical treatment

Question 11

What is radiation?

Answer 11

Use of EM and particulate ionizing raidation

Question 12

How is the dose of radiation measured?

Answer 12

Gray

Question 13

What is the most common form of radiation?

Answer 13

Daily external delivery of photons i.e. x-rays over multiple weeks

Question 14

Why is external beam radiation therapy given over time?

Answer 14

This is required for maximal tumor kill and minimal damage to normal tissue damage

Question 15

What does radiosensitive mean?

Answer 15

Tumor melts with radiation

Question 16

What does radioresponsive mean?

Answer 16

Tumor melts quickly with radiation

Question 17

What is Brachytherapy?

Answer 17

Any source that emits a halo of radiation

E.g. prostate seeds

Question 18

What is the most important lesion induced by radiation?

Answer 18

Double strand DNA break

Question 19

What is the most radiosensitive phase of the cell cycle?

Answer 19

M/G2

Question 20

What is the radioresistant phase of the cell cycle?

Answer 20

S

Question 21

What is the RT in radiation therapy? What are the implications?

Answer 21

Theraputic ratio of radiation, like a TI

The bigger the number the more cancerous tissue is specifically targeted

Question 22

Why are hypoxic cells the most radioresistant?

Answer 22

Oxygenation enhances ds-DNA breaks

Question 23

What part of tumors is the most hypoxic?

Answer 23

Central portion

Question 24

What is the standard dose of radation?

Answer 24

180-200 cGy per day

Question 25

What is hypofractionation dose radiation?

Answer 25

Very high dose radiation

Question 26

What types of cancer are typically radiated for palliative reasons?

Answer 26

Brain mets | Bone mets

Question 27

What are the five levels of treatment complexity in radiation?

Answer 27

1) Non-planned 2) 2D 3) 3DCRT 4) IMRT 5) SRS/FSRT/SBRT

Question 28

What is 3D-CRT?

Answer 28

- Computer based treatment plan - Designs treatment to target the tumor and avoid normal structure *****Causes a "leaking" or radiation into nearby critical structures*****

Question 29

What is IMRT?

Answer 29

Intensity-modulated radiation therapy (IMRT) is a high-precision radiotherapy that uses computer-controlled linear accelerator to deliver precise radiation doses to a malignant tumor ****This prevents harm to surrounding structures and is at limiting collateral damage than 3D-CRT*****

Question 30

What is SRS?

Answer 30

Stereotactic Radiosurgery ****This creates an x,y, and z axes to localize brain lesions*****

Question 31

What is the cyber knife?

Answer 31

Robot used today for brain tumor localization

Question 32

What is the definition of GTV?

Answer 32

Gross Tumor Volume i.e. the volume of tumor that can be imaged

Question 33

What is the definition of CTV?

Answer 33

Clinical Target Volume, the gross tumor volume plus the margins of assumed sub-clinical disease

Question 34

What is the definition of ITV?

Answer 34

Internal Target Volume,this is a volume that accounts for the movement of the CTV in a patient

Question 35

What is the definition of PTV?

Answer 35

Panning target volume, a volume intended to compensate for errors in planning and set up

Question 36

What does OAR stand for?

Answer 36

Organs at Risk

Question 37

Why is a CT done for every patient?

Answer 37

Planning

Question 38

What is "fusion?"

Answer 38

Fusion of the planning CT and other imaging modalities

Question 39

What are photons best for treating?

Answer 39

Deep lesions

Question 40

What are electrons best for treating?

Answer 40

Superficical lesions

Question 41

What type of beam block is the current standard of care?

Answer 41

Multileaf Collimator (MLC)

Question 42

What is a portal film?

Answer 42

Image used to verify the correct setup for radiation based on bony landmarks

Question 43

What is IGRT?

Answer 43

Image Guided Radiation Therapy This is a special imaging technology that allows the physician to image the tumor immediately before or during the time radiation is delivered. These images are then compared to the reference images taken during simulation. Any necessary adjustments are then made to the patient's position and/or radiation beams in order to more precisely target radiation at the tumor and avoid healthy surrounding tissue.

Question 44

What is stereoscopic IGRT?

Answer 44

This is an imaging technique, IGRT, that uses bones as landmarks *****It is difficult to use for deep soft tissue targets are there are no bony landmarks in close proximity******

Question 45

What is stereoscopic IGRT poor for?

Answer 45

Soft tissue targets

Question 46

What is cone beam IGRT best for?

Answer 46

Soft tissue targets