treatment of cancer Pt1 Flashcards
in radiation what is DNA showered with
photons
2 ways photons can act on DNA
direct action
indirect action
direct action of a photon=
photon expels an electron from the molecule which directly damages the DNA
indirect action of a photon=
causes free radical generation which then damages the DNA
what molecule does indirect action require
oxygen
what type of tumour doesn’t respond well to radiotherapy
hypoxic tumours
what happens to a cell when it undergoes a lot of damage
apoptosis
2 types radiotherapy
external
internal
external radiotherapy=
external beam radiotherapy
internal radiotherapy
brachytherapy
4 types of external radiotherapy
conventional
stereotactic
particle
3-D conformal
how is conventional radiotherapy delivered
two-dimensional beams using kilovoltage high energy X-rays
what can limit conventional radiotherapy
radiation toxicity to near by healthy tissue
what is stereotactic radiation
uses focused beams targeting a well defined tumour using detailed CT scanning
what type of tumour is stereotactic used for
small tumours
what is particle radiation
using energetic ionizing particles directed at the tumour
benefit of particle radiation
less energy deposited into healthy tissue
what is 3-D conformal radiotherapy
the profile of each beam is shaped to fit the profile of the target using a multileaf collimator
what does 3-D conformal radiation allow
higher dose of radiation to be delivered to the tumour
what is brachytherapy
radiation source inside or next to the area requiring treatment
2 stages of reaction to radiotherapy
acute tissue reaction
late tissue reaction
5 acute side effects of radiotherapy
- epithelial damage
- mouth, throat, stomach sores
- intestinal discomfort
- swelling of soft tissue
- infertility
4 late side effects of radiotherapy
- fibrosis
- hair loss
- dryness
- lymphedema
xerostomia=
dry mouth
