Internal radiation — brachytherapy

Internal radiation (also known as brachytherapy) involves placing radioactive seeds or wires, such as caesium, iridium, or iodine into the body close to the cancer.

Why is brachytherapy used? This is to give higher doses of radiation exactly where the cancer is without having to go through healthy tissue.

High dose rate prostate implants deliver radiation to the prostate with two to four treatments using a single, small radioactive iridium source on the end of a computer controlled flexible wire. This radioactive source delivers the radiation by travelling through narrow tubes called catheters

Brachytherapy for gynaecological cancer

High dose rate (HDR)

Hollow plastic or metal tubes (applicators) are inserted into the vagina. A machine feeds small 5mm radioactive metal rods (the source) into the tubes. The tubes are put in position under a general anaesthetic but for some treatments a spinal anaesthetic or light sedation might be used instead.

Each treatment takes about 10-20 minutes. There might be a number of treatments to complete the course. In some New Zealand centres, treatment is given over several days. Once the radiation treatment has finished, the applicators are removed by a doctor or nurse. This might be after each treatment or only at the end of the full course of treatment.

You will need to stay in bed during the treatment. You might need to have a tube (catheter) put into your bladder to drain away any urine.

Internal radiation treatment might be uncomfortable and the staff will make sure that you are made comfortable and given pain relief to minimise any discomfort.

Source: Cancer Backup 2008

Brachytherapy for prostate cancer

Low dose rate (LDR)

Tiny radioactive seeds are inserted permanently into the prostate gland. This form of treatment can be successful for small tumours which are located within the gland. Depending on your cancer, prostate brachytherapy might be combined with external beam therapy.

X-ray showing permanent radioactive seeds

Image Above: This X-ray shows permanent radioactive seeds used for low dose rate brachytherapy in the prostate gland. (a): Multiple strands of seeds evenly spaced throughout the prostate gland.

“I can’t believe that they put 123 of those little things [seeds] at different strengths at different locations in something the size of a walnut.” Paul

For about two months after the treatment, children and women who are pregnant (or who might be) should not stay very close to you for long periods of time. However, it is safe for them to be in the same room as you. If you are resuming sexual intercourse, condoms should be used for two weeks after your seed implantation. This is in case a seed accidentally moves and is ejaculated in the semen.

Low dose rate brachytherapy is currently only available in the private hospital system.