Radiation therapy Exam A+ Pass 2025
New Update
3 types - Answer- Orth voltage - external
Brachytherapy - internal
Tele therapy
Aim - Answer- To deliver as high dose possible to tumour while limiting dose to
surrounding healthy tissues
Interested in the absorbed dose
Unit of dose = gray
4 R's of radiology - Answer- Repair
Regeneration
Repopulation
Deoxygenation
Cancer - Answer- Cell division out of control
Neoplasm = tumor
Diagnosis - Answer- Classification of tumor as either benign or malignant
Benign = Not fatal. Usually encapsulated. Grows very slow.
Malignant = Fatal. Usually not encapsulated. Rapid growth.
Staging - Answer- Determining tumor size and spread
TNM - staging based on histology/pathology
Grade 1 = Well differentiated. Looks like cell type it should be
Grade 2 = moderately well differentiated. Looks abnormal
Grade 3 = poorly differentiated. Looks very abnormal. Fast growing.
General staging
Stage 1 = Tumour confined to organ of origin
Stage 2 = Local lymph nodes invaded
Stage 3 = Distant nodes invaded OR local spread beyond organ of origin
Stage 4 = Blood borne Metastases present
Treatment types - Answer- Local treatment
- Surgery, radiation therapy
Systemic treatment - kills every ew cell that reproduces.
, - Chemotherapy, Immunotherapy, Hormone therapy
Radical - aims to cure
Palliative - aims to make comfortable, prompt relief of symptoms
Radiation, medical and surgical oncologist - Answer- Radiation - specialist cancer
doctor who is responsible for prescribing radiation
Medical - specialist cancer doctor who is responsible for prescribing chemotherapy
Surgical - specialist cancer doctor who is responsible for the surgical intervention
Patient pathway - Answer- Medical consult
Planning CT - dataset is taken
Plan optimization - dataset is used to decide the best beam arrangement
Treatment
Treatment procedure:
- Appointment
- Waits for RT to call them
- Initial chat
- Patient gets changed and waits for treatment
- Taken into treatment room and positioned
- Images are taken to confirm correct position
- Treatment delivered
Post treatment - Answer- Patient will see radiotherapy nurse to discuss supportive care
for side effects. Can refer them to other specialists such as:
- Dietician, dentist, counselling, nursing at home care, dermatologist
Linac Accelerator - Answer- Machine that produces radiation (high energy X-rays)
Produces a range of photon beams
Gantry: 360 degrees. 180 each way
Treatment couch: 3 planes (longitudinal, lateral, vertical) and Rotation
Collimators: "Head" - rotates to change the field angle. "Jaws" - move to define field
size.
Secondary beam Collimation:
- MLC - built into machine head. Move to match the shape of the tumour
- Blocks - manually added to machine. Stuck onto a shielding tray
Isodose lines - Answer- Points of equal dose joined into lines
The value assigned to each line can be a percentage or the absolute dose
GTV
CTV
PTV - Answer- Gross target volume - what we can physically see or palpate
New Update
3 types - Answer- Orth voltage - external
Brachytherapy - internal
Tele therapy
Aim - Answer- To deliver as high dose possible to tumour while limiting dose to
surrounding healthy tissues
Interested in the absorbed dose
Unit of dose = gray
4 R's of radiology - Answer- Repair
Regeneration
Repopulation
Deoxygenation
Cancer - Answer- Cell division out of control
Neoplasm = tumor
Diagnosis - Answer- Classification of tumor as either benign or malignant
Benign = Not fatal. Usually encapsulated. Grows very slow.
Malignant = Fatal. Usually not encapsulated. Rapid growth.
Staging - Answer- Determining tumor size and spread
TNM - staging based on histology/pathology
Grade 1 = Well differentiated. Looks like cell type it should be
Grade 2 = moderately well differentiated. Looks abnormal
Grade 3 = poorly differentiated. Looks very abnormal. Fast growing.
General staging
Stage 1 = Tumour confined to organ of origin
Stage 2 = Local lymph nodes invaded
Stage 3 = Distant nodes invaded OR local spread beyond organ of origin
Stage 4 = Blood borne Metastases present
Treatment types - Answer- Local treatment
- Surgery, radiation therapy
Systemic treatment - kills every ew cell that reproduces.
, - Chemotherapy, Immunotherapy, Hormone therapy
Radical - aims to cure
Palliative - aims to make comfortable, prompt relief of symptoms
Radiation, medical and surgical oncologist - Answer- Radiation - specialist cancer
doctor who is responsible for prescribing radiation
Medical - specialist cancer doctor who is responsible for prescribing chemotherapy
Surgical - specialist cancer doctor who is responsible for the surgical intervention
Patient pathway - Answer- Medical consult
Planning CT - dataset is taken
Plan optimization - dataset is used to decide the best beam arrangement
Treatment
Treatment procedure:
- Appointment
- Waits for RT to call them
- Initial chat
- Patient gets changed and waits for treatment
- Taken into treatment room and positioned
- Images are taken to confirm correct position
- Treatment delivered
Post treatment - Answer- Patient will see radiotherapy nurse to discuss supportive care
for side effects. Can refer them to other specialists such as:
- Dietician, dentist, counselling, nursing at home care, dermatologist
Linac Accelerator - Answer- Machine that produces radiation (high energy X-rays)
Produces a range of photon beams
Gantry: 360 degrees. 180 each way
Treatment couch: 3 planes (longitudinal, lateral, vertical) and Rotation
Collimators: "Head" - rotates to change the field angle. "Jaws" - move to define field
size.
Secondary beam Collimation:
- MLC - built into machine head. Move to match the shape of the tumour
- Blocks - manually added to machine. Stuck onto a shielding tray
Isodose lines - Answer- Points of equal dose joined into lines
The value assigned to each line can be a percentage or the absolute dose
GTV
CTV
PTV - Answer- Gross target volume - what we can physically see or palpate
