Lec 06 Radiation Oncology Flashcards Preview

OS 217 Oncology > Lec 06 Radiation Oncology > Flashcards

Flashcards in Lec 06 Radiation Oncology Deck (24)
Loading flashcards...
1
Q

What is the difference between Ionizing and Non-ionizing radiation?

A

Ionizing radiation carries enough energy to remove and electron from an atom

2
Q

What are the two types of Ionizing radiation?

A

particulate and EM

3
Q

What is the primary target of radiotherapy?

A

DNA

4
Q

In general, cells are most radiosensitive during which phases of the cell cycle?

A

M and G2 phases

5
Q

In general, cells are most resistant to radiotherapy during which phase of the cell cycle?

A

late S phase

6
Q

What is the difference between the direct and indirect action of radiation?

A

Direct - radiation causes damage by interacting with the chemical bonds of DNA
Indirect - radiation interacts with water, causing the formation of hydroxyl radicals which cause the actual DNA damage

7
Q

What are the steps in the radiation oncology process?

A
  1. consultation
  2. simulation
  3. treatment/planning
  4. radiation therapy
  5. follow up
8
Q

What is the purpose of a thermoplastic mask/mesh?

A

stabilization of the head during radiotherapy

9
Q

What are the two emergencies in radio oncology?

A
  1. superior vena cava syndrome

2. cord compression

10
Q

What are the two types of imaging simulations?

A

conventional (X-ray), CT simulation

11
Q

What is target volume?

A

volume that the radiation oncologist has defined to receive the prescribed dosage of radiotherapy

12
Q

What is treated volume?

A

volume encompassed by a clinically significant isodose surface/line (usually 95%)

13
Q

What is irradiated volume?

A

volume that corresponds to a dose relevant to the normal tissues that surround the target volume

14
Q

What are the different types of treatment planning?

A

Conventional - 2D based approach using a calibrated fluoroscopy machine that simulates the beam characteristics of a linear accelerator

Conformal - beams are modified to conform to the shape of the target based on information from the CT simulation

3D CRT Intensity Modulated RT (IMRT) - CT images used to contour target and normal structure, dose to the tumor and organs at risk can be calculated

15
Q

How often should post-therapy check-ups be done?

A

weekly

16
Q

What is brachytherapy?

A

radioactive source placed close to the target tumor

17
Q

What are some radioactive substances commonly used in brachytherapy?

A

cesium-137
cobalt-60
iridium-192
iodine-125

18
Q

When is surface brachytherapy done?

A

skin malignancies like basal cell or squamous cell carcinoma

19
Q

What is the position of patients during the insertion of applicators for intercavitary brachytherapy for cervical CA?

A

dorsal lithotomy

20
Q

What is teletherapy?

A

external beam radiation therapy

21
Q

What are the steps in EBRT?

A

Simulation: Imaging and Immobilization
Target Delineation and Dose Calculation
Translation/Verification

22
Q

When is stereotactic radiosurgery used?

A

small brain tumors

23
Q

When is stereotactic body radiotherapy (SBRT) indicated?

A

any tumor

24
Q

What are some possible side effects of head and neck irradiation?

A

dry mouth, difficulty swallowing, mouth and gum sores, jaw stiffness, nausea, lymphedema, tooth decay