What is Brachytherapy?
Brachytherapy is a type of radiation therapy in which radioactive materials are placed inside a patient’s body temporarily or permanently to kill cancer cells.
Brachytherapy is a form of radiation therapy called internal radiation therapy, as opposed to external beam radiation therapy in which radiation is generated from an external machine and directed at a tumour in the patient’s body.
What are the types of brachytherapy?
There are two types of brachytherapy: Permanent and temporary brachytherapy.
In temporary brachytherapy, a highly radioactive material is placed inside a catheter and inserted into the tumour or close to it. After a specified period of time, the catheter is removed.
In permanent brachytherapy, the radioactive materials are placed as seeds or pellets in or close to the tumour and left there permanently. While in place, the radioactivity level of the radioactive seeds diminish gradually till it reduces to nothing. It is not taken out of the patient’s body, but left in place posing no health risks to the patient.
How is brachytherapy performed?
A team consisting of a radiation oncologist, radiation therapist, medical physicist, radiation nurse, and a dosimetrist would be needed to achieve the delivery of brachytherapy.
These medical personnel determine how much radiation would be required for treatment of the cancer, the appropriate mode of delivering the therapy, and how much radiation is safe for structures around the tumour.
Prior to the brachytherapy procedure, the physician would schedule you for some pre-treatment tests including blood tests, chest X-ray, and radiological imaging of the tumours to be treated. Additionally, you would receive an appropriate form of anaesthesia before the procedure begins.
In permanent brachytherapy, a needle is used to insert the radioactive seeds into the tumour. This implantation may be done with the aid of imaging modalities such as ultrasound or MRI scans. After insertion of the seeds, these imaging studies would also be used to confirm that they have been well positioned.
In temporary brachytherapy, a needle or catheter is used to introduce the radioactive material into your body. Treatment in temporary brachytherapy may be delivered at high dose-rate which lasts for about 10 to 20 minutes or low dose-rate which last several hours and up to two days. Treatment could also be delivered in pulsed dose-rate, in which case, the radioactive material is delivered in periodic pulses.
With temporary brachytherapy, you would stay in the hospital until treatment is completed. After treatment, the radioactive materials are removed from your body and you pose no health threat to those around you. However, if you are on permanent brachytherapy, you would need your doctor’s counsel on limiting contact with certain people especially pregnant women and children.
How does brachytherapy work?
Brachytherapy works like other forms of radiotherapy. The ionizing radiation from the radioactive materials breaks up the DNA of cancer cells, disrupting their ability to divide, thereby killing them and causing regression of the tumour.
What health risks are associated with brachytherapy?
Health risks of brachytherapy stem from the fact that radiation affects both cancer cells and healthy ones. However, cancer cells are more vulnerable because they divide faster. Long-term risks of brachytherapy include sterility and development of a second cancer.