Radiation overview Flashcards
What are the three most common cancers in men?
prostate
lung and bronchus
colon/bladder
What are the three most common cancers in women?
breast
lung
colorectal
What are the four most common causes of death d/t CA in men?
Lung
prostate
Colorectal
Pancreas
What are the four most common causes of death d/t CA in women?
lung breast colorectal pancreas ovary
What are the four basic patterns of spread?
Local growth
local extension
lymph node mets
Hematogenous mets
Anyone who has M stage (__) or higher has what***
What are the four modalities of medical therapy treatment for CA?
chemo
hormone
biological
vaccine
What is the role of radiation?
Replace or complement surgery
What CAs are exclusively treated with radiation?
anal cancer
small cell lung (mostly)
Stage IIIB NSCLC
small cell lung cancers are found exclusively in whom?
those who smoke
What is the role of radiation in esophageal CA?
ok to treat without surgery
What is the role of radiation in breast cancer?
removes margins after surgery
What is the role of radiation in skin cancer?
After surgery adjuvant
What is the role of radiation in prostate cancer?
adjuvant to surgery
What is the role of radiation in uterine/endometrial cancer?
adjuvant
Dose of radiation is measured in what?
gray
What is the most common timing of radiation dosing?
Daily over multiple weeks
Why are small doses over a long period of time needed to treat CA?
Kill tumors, and not normal cells
What is radiosensitive?
Tumor “melts” with radiation
What is radio responsive?
melts quickly
What is brachytherapy?
beads that radiate small halos of radiation
What is the linear accelerator used in radiation therapy?
machine that emits photons and particles
Why is linear accelerators used for kids?
no leftover radiation
What is the MOA of radiation in treating tumors?
double stranded breaks in the tumors
What is the wanted relationships between tumor control probability and normal tissue complication probability?
very wide difference
What is the relationship between radiation dose and cell kill?
Non-linear, but negative trend
What is the relationship between oxygen and radiation effectiveness?
More oxygen = more kill
thus need multiple doses to get to hypoxic center
What is hyperfractionation?
very small doses of radiation x2/day
What is the dosage for standard fractionation?
180-200 cGy /day
What is hypofractionation?
Massive dose of radiation to tumors (melanoma)
What is the “long shoulder” of CA?
Little effect until high doses of radiation
What cancer is cured with radiation?
prostate CA
What cancer have a neoadjuvant therapy with radiation?
esophageal CA
What cancer has radiation as an adjuvant therapy?
breast CA
Palliative treatment with radiation is used with what CAs?
brain mets causing neurological symptoms
What is the simulation part of the TP process?
see if pt will tolerate the restraints needed to treat CA
What is the treatment planning part of TP process?
angle beam correctly
What are the 5 levels of radiation treatments?
- non planned
- 2d
- 3d
- IMRT
- SRS/SBRT
What is 3D-CRT?
Designs the treatment fields so that the angle of the treatment treats the tumor and avoids normal structures as much as possible
What is IMRT?
like 3D-CRT but different portions of the treatment get different doses of the radiation via very small radiation “shots”
What is cranial stereotactic radiosurgery?
Using super small doses in the brain
What is gross tumor volume?
Gross demonstrable extent of the tumor
What is the CTV?
Margi on GTV that accounts for disease spread
What is ITV?
CTV + internal margin for physiological movements
What is PTV?
CTV or ITV + setup margin for pt movement
What is OAR?
organ at risk/critical structure
What is the fusion bit for planning?
Taking different imaging modalities to label out the tumor
True or false: photons are “skin sparing”
True
Which are most effective at deep tissue tumors: photons or electrons
Photons
What is a multileaf collimator?
lead block to focus radiation
What is image guided radiation therapy?
Using imaging with implanted markers to target tumors that move physiologically to align tumors
What is cone beam IGRT?
CT scan on each visit, to allow for comparison of soft tissue anatomy
