Radiation Oncology Flashcards
what does depth of penetration of ionizing radiation vary by?
energy
what does dose of radiation vary based on?
tumor type
location
treatment goals
long-term side effects
what is definitive radiation like?
more of curative intent
prevent local tumor regrowth
improve life expectancy
what is a side effect of radiation in the lungs?
fibrosis
what is the risk of radiation associated tumors?
2%
what tumor locations warrant radiation treatment planning?
nasal tumors
brain tumors
heart base tumors
abdominal tumors
for what neoplasias is radiation recommended?
acanthomatous ameloblastoma
squamous cell carcinoma
soft tissue sarcoma
malignant melanoma
nasal tumors
which squamous cell carcinomas do not respond to radiation well?
tonsillar squamous cell carcinoma
cats
what are canine nasal tumors commonly associated with?
epistaxis
what most commonly causes feline nasal tumors?
lymphoma
what is radiation?
high energy photons and electrons are generated by a linear accelerator
are photons or electrons high energy?
photons
is radiation from linear accelerators absorbed systematically?
no
where do electrons deliver energy to?
surface
what are the types of direct DNA damage?
single strand bread
double strand break: lethal, cell death
what is radiation dose calculated in?
units of gray/Gy
what is stereotactic radiation?
type of definitive radiation therapy
tumor ablative
high dose over a short time
why is radiation delivered with fractionation (over time)?
to allow normal tissues to repair and repopulate
when are acute radiation side effects seen?
first 1-3 months
effects directly proportional to dose
where can acute side effects be worse?
in head and neck region
what types of tissues do late side effects impact?
slowly growing tissues
lungs
eye
hair
when is radiation used for palliative treatments?
bone tumors
tumors with minimal or no treatment options
what is acanthomatous ameloblastoma?
benign tumor that is locally malignant
required removal of bone to achieve good margins
arises from odontogenic ligament
how is oral malignant melanoma treated?
palliative radiation acts like definitive radiation therapy
response rates >80%, remission 44-70%
what can cause canine nasal tumors?
carcinoma
adenocarcinoma
rarely sarcoma
do cats or dogs tend to have fewer side effects to radiation therapy?
cats
