Radiotherapy Flashcards
Define radiotherapy.
Use of ionizing radiation to induce damage to DNA in cells.
What is the target in radiotherapy?
Unrepaired or misrepaired double strand breaks.
Define the therapeutic ratio.
The probability of tumour control and the likelihood of normal tissue damage.
Define the differential effect.
The effect of applying one treatment in lieu of the other.
Define Fractionation.
Aimed at increasing the therapeutic ratio (improve tumour control while sparring normal tissues).
What do the 4R’s in Fractionation refer to?
Repair. Repopulation. Redistribution. Reoxygenation.
State the the 3 types of Radiotherapy.
External beam. Brachytherapy. Radio-active isotopes.
Define Brachytherapy.
Places radioactive sources INSIDE patient to kill cancer cells and shrink tumours.
Define External Beam.
Photons - linear accelerators, cyber gamm.
Define Radio-active Isotopes.
E.g. iodine in drink form is absorbed into the body and picked up by thyroid cancer cells.
Define Stereotactic Radiotherapy.
Radiotherapy from many different angles around the body. Beams meet at the tumour. Tumour receives high does and tissues around receive low dose radiation.
State a feature of radiotherapy.
Compared to surgery (organ preservation, no operative risk).
Compared to chemotherapy (no significant haematoloigcal toxicity, infection risk).
What are the 2 alternative purposes of radiotherapy?
Radical (cure tumour, high dose, longer course). Palliative (relieve symptoms, lower doses, shorter course.
State the stages to Radiotherapy Planning.
Positioning & Immobilisation. CT scanning. Target definition. RT planning.
State the Treatment Delivery & Care
Verification. Treatment. Pt care.
State the 3 aspects of Radiotherapy Process/Pathway.
Assessment & Consent. Radiotherapy Planning. Treatment Delivery & Care.
State 2 acute side effects of Radiotherapy.
General - Fatigue, Skin reaction Brain - Nausea, Somnolence Chest - Oesophagitis, Pneumonitis, Rib/chest wall tenderness Abdomen - Nausea, Diarrhoea Pelvis - Diarrhoea, cystitis
State 2 late side effects of Radiotherapy.
General - second malignancy
Brain - cognitive and memory impairment
Chest - lung fibrosis, cardiac problems
H&N - Dry eye, cataract, dental problems, mandible necrosis
Abdomen - intestinal irritability, kidney damage, liver damage
Pelvis - proctitis, impotence, vaginal dryness, infertility.
State the preventative measures after Radiotherapy.
Skin care advice. Anti-emetics. Oral hygiene. Dietary review.
State the symptomatic treatment after Radiotherapy.
Loperamide. Analgesia. Nutritional support. Skin reaction treatment. Rest from treatment.
State the long term effects after Radiotherapy.
Follow up late effects. Screening for certain late effects e.g. Breast Ca screening after mediastinal RT for lymphoma, TFTs after neck RT, Dental check ups after mouth RT. Treatment e.g. thyroxine replacement.
