Radiation Oncology Flashcards
RT is a _____ tx
locoregional
surgery is a ____ tx
local
chemo is a ____ tx
systemic
about ____ % of all incident cancer cases require RT at some point
50%
modern RT uses high energy ___
xrays
what is the logic behind using xrays to kill cancer cells
Main target of ionizing radiation = cell’s nuclear DNA
When enough DNA damage accumulates = cells can no longer divide = cell death
Cancer cells can not repair DNA damage as effectively as normal tissues = preferentially killed by RT
what is the most common type of RT
external beam
the higher the energy the _____ the radiation penetrates into target tissue
deeper
what are the 2 types of RT
external beam
brachytherapy
what is brachytherapy
internal radiotherapy from radioactive implants that may be permanent or removable
intent is to deliver high dose radiation to tumor while limiting absorption from surrounding tissues
how often do you get RT
5 days a week
2 RT treatments = ____ fraction
2
1 Gy = ____ cGy = ____ rad
1gy = 100cGy = 100rad
what are radiosensitizers?
chemicals that increase biologic effects of RT
what are some chemo agents that are also radiosensitizers
5FU
cisplatin
5FU is used with RT for ______ cancer
rectal
cisplatin is used with RT for _________________________ cancer
head/ neck
lungs
cervical
bladder
RT to ______ if Post lumpectomy, lymph node negative
breast
RT to ______ if Post lumpectomy, lymph node positive
breast + regional lymph node
RT to ______ if Post mastectomy, lymph node positive
entire chest region + regional lymph nodes
RT to ______ if, low risk prostate cancer
prostate only
RT to ______ if, intermed risk prostate cancer
prostate + proximal seminal vesicles
RT to _______ if high risk prostate cancer
prostate + proximal seminal vesicles + pelvic lymph node
____________, a form of IMRT (intensity modulated radiotherapy) = allows a high dose of conformal RT to the target volume, while sparing surrounding normal tissues
rapid arc tx planning
what % of RT is given with palliative intent
50%
what is one of the only RT emergencies
spinal cord compression
what is a CT simulation
a scan is taken of the area of the body to be treated, so that radiation can be planned
what do you need when doing a CT simulation for brain/ head/ neck tumors
mask to keep head still
planning of a CT scane is done by
radiation oncologist
calculations and prep for CT are done by
radiation therapists and dosimetrists
what is the only generalized SE of RT
fatigue
what are some early SEs of RT
- general
- RT over abdominal/ pelvis
- RT over chest
skin redness and irritation
- RT over abdomen/ pelvis = nausea and diarrhea
- RT over chest = esophagitis
early SE of RT are usually
1. common but self limited
2. severe and permanent
3. severe and requires immediate attention
4. nonsevere and permanent
- common but self limited
late SE of RT are usually
1. common but self limited
2. uncommon and permanent
3. severe and requires immediate attention
4. nonsevere and permanent
2
what is the criteria of diagnosing a secondary malignancy from RT
Within or at border of RT field
Previously normal tissue
Latent period exists (=>3yrs)
Histologically proven different from primary cancer
