Radiotherapy is a very useful tool in the treatment of cancers. There are numerous types of radiation and your Oncologist will discuss the specifics with you should you require this treatment.
Radiotherapy uses ionising radiation to deliver a dose of energy to the tumour. With the newest techniques available, we are able to deliver the dose required to the tumour volume as accurately as possible while minimising the effects on the surrounding normal tissue as much as possible.
Radiation therapy cannot just happen. It is a process that requires careful planning and teamwork. Most planning is done with the use of a planning CT scan that allows your Oncologist to delineate a target volume that they wish to treat. Once this has been done, the planning process can happen. This involves the input of planning radiotherapists and medical physicists who, together with the Oncologist, plan how best to deliver your radiation therapy. Depending on the difficulty or complexity of the plan, this process can take up to 2 weeks to complete.
With this form of treatment, one is positioned on a bed and the machine delivering the dose to the tumour/target volume is situated away from you. You are asked to lie as still as possible during this treatment to ensure that the target volume treated is the same every day. Treatment times vary from a few minutes up to 20 minutes. Side effects from this therapy vary according to the site treated and are related to the normal surrounding tissue and the effect the radiation has on this tissue. To deliver an adequate dose to the target volume, treatment is required on multiple consecutive days (excluding weekends). This allows for us to deliver a dose of radiation that is deemed adequate to control disease, but at the same time, minimises damage (both short and long-term) to the surrounding normal tissue. Stereotactic radiosurgery and fractionated stereotactic radiotherapy are specialized types of external beam radiotherapy that utilize specialized equipment to precisely target some types of tumours and benign lesions.
Brachytherapy involves the insertion of a radiation source into a tumour. There are limited applications of this type of treatment and it can be used either on its own or in combination with external beam therapy. The most common types of cancers that require this therapy are prostate, cervix and endometrium.
The most common use of radioactive isotopes is for thyroid cancers where radioactive iodine is administered orally to ablate the residual thyroid tissue after surgery for a thyroid cancer.