radiotherapy Flashcards
describe what conformal radiotherapy is
external radiotherapy - 3D CRT
use of metal blocks to direct beam of ioning radiation
what is conformal radiotherapy used to treat?
prostate cancer
name types of internal radiation and their uses
strontium 89 - bone cancer
samarium 153 - bone cancer
iodine 131 - thyroid gland
radium 223 - secondary bone cancer
what is the procedure for external radiotherapy?
lie motionless
each fraction takes around 5 mins
painless
describe the procedure for giving internal radiotherapy
give IV or liquid form
radioactive wires or seeds (radioactive gold or iodine) put into affected area
which types of radiation are most likely to cause tissue damage and are used in radiotherapy?
alpha and gamma
how does ionising radiation work?
penetrates tissues and alters nuclear material ie. disrupting cell growth and reproduction - damaging human cells by apoptosis.
when high energy ray hits cell it breaks up producing free radicals which can cause further damage
describe the procedure of internal radiotherapy
a few days - wires or IV
permanent - seeds inserted in tumour which degrade over time
which type of radiation is used in internal radiotherapy?
alpha - shorter wave (more powerful)
what are the side effects of radiotherapy?
tiredness (amaemia, bone marrow affected)
sore skin (local reaction)
N & V (during or after) - prescribe antiemetics
loss of appetite
muscle & joint stiffness (swelling of joint)
fertility (early menopause / loss of libido)
how can radiotherapy be used to treat graves’ disease?
implant radioactive seeds into thyroid gland - reduces activity by destroyed cells
describe hyperfractioned radiotherapy
increasing frequency of fractions eg. continuous hyperfractionated accelerated radiotherapy
total dose same
describe hypofractionated radiotherapy
increased dose of radiotherapy per fraction but lower frequency
overall reduction in amount
what is stereotatic radiotherapy?
targeted delivery from many different points on head - external frame used
what is stereotatic radiotherapy used for?
small round tumours in head eg.
pituitary adenomas
acoustic neuromas
meningiomas
