Treatment Modalities - Radiotherapy

What is radiotherapy?

The use of ionising radiation to treat mainly malignant disease.

What is the primary aim of radiotherapy?

To deliver maximum dose to the tumour and minimum dose to surrounding normal tissue.

Rationale for fractionation in radiotherapy

Normal tissues repair radiation damage better than chaotic tumour structures.

What percentage of cancer patients benefit from radiotherapy?

50% of all cancer patients will benefit from receiving radiotherapy.

Main types of radiotherapy

External beam radiotherapy (EBRT), brachytherapy, and particle therapy.

External beam radiotherapy (EBRT) using Photons (MV) is ideal for:

Deep-seated tumours in any part of the body.

External beam radiotherapy using Electrons (MeV) is ideal for:

Superficial tumours from the skin surface to a depth of approximately 5cm.

Kilovoltage superficial (SXR) radiotherapy is ideal for:

Basal cell carcinomas (BCCs), penetrating no more than 1cm beneath the skin.

What is the standard FAD/SAD distance in isocentric movement?

100 cm.

Brachytherapy

A mode of treatment where radioactive sources are placed in close or direct contact with tissue.

Four delivery methods of brachytherapy

Intracavitary, intraluminal, interstitial, and surface applicators (mould treatments).

Examples of brachytherapy radioactive sources

Iridium-192, Gold-198, Caesium-137, and Cobalt-60.

Radical radiotherapy

Treatment given with the intent of long-term control or cure for the patient.

Palliative radiotherapy

Treatment given to improve quality of life for a patient with no implied impact on survival.

Prophylactic radiotherapy

Precautionary treatment to prevent disease, such as treating microscopic undetectable spread.

Neo-adjuvant treatment

Treatment delivered before primary surgical treatment to reduce tumour size.

Adjuvant treatment

Treatment delivered post-operatively to eradicate micro-metastases and reduce recurrence risk.

What is the unit of absorbed radiation dose?

Gray (Gy), where 1Gy equals 1 Joule of energy absorbed in 1kg mass.

Haemoptysis definition

Coughing up blood.

What does MSCC stand for?

Malignant spinal cord compression.

What does SVCO stand for?

Superior vena cava obstruction.