Radiotherapy Flashcards
Preferred treatment for malignancies?
Alpha
Gamma
Beta
Neutrons
Alpha, gamma
More likely to cause tissue damage as more effective in producing ionisation.
Radiotherapy is used to….
Treat cancer Shrink Timor Reduce return after surgery Control symptoms Reduce growth of cells, Graves' disease
Each exposure to radiotherapy is called….
A fraction
Ionising radiation
Penetrates tissues and alters nuclear material
High energy Ray hits particles they break up, forming free radicals that can cause further damage to cell.
External radiotherapy
Given over several days or weeks
Mon-fri weekend off
Mark target area
Lie motionless
5 mins per fraction
Painless
Radiotherapy machine works by….
Metal element is heated to produce electrons
These accelerate in an electric field towards tungsten metal
This emits high energy X-rays
Conformal radiotherapy
Uses metal blocks to direct ionising radiation
More closely target shape of tumour
Routinely used for prostate cancers
Internal radiotherapy
Once or few times, require stay in hospital
Radioactive wires or seeds put in area
Left and degrade over time
Radiation levels monitored with Geiger counter
Limit contact with people
Liquid /iv internal radiotherapy
Strontium 89 , samarium 153- bone cancers
Radium 223 secondary bone cancer trials
Iodine 131 thyroid gland
Side effects of radiotherapy depend on…
Depend on :
Area
Dose
Physical health at time of treatment
Can appear during or weeks after
Examples of side effects of radiotherapy
Tiredness Nausea, sickness Sore skin Muscle, joint pain Fertility problems
Radiotherapy and the thyroid gland
Used to treat Graves’ disease
Less t3 t4 released
Future of radiotherapy
Hyper fractionated - increase frequency of fractions, reduce time scale
Hypo fractionated - higher dose per fraction, less fractions
Stereotactic radiotherapy is…
Used to treat small round tumours in head
Used in benign conditions:
Pituitary adenomas
Acoustic neuroma
Meningiomas
Eg: radio surgery but used for bigger tumours
Proton and ion beam radiation
Hope to be used in the future
Does not use ionising radiation
Asha king used this in Prague
