There are two main types of brachytherapy treatment: temporary and permanent. Temporary treatment involves the placement of radioactive material in or close to a tumor for a limited period of time before it is removed, whereas permanent treatment involves leaving the radioactive material in the body and allowing its levels of radioactivity to diminish naturally. Within these two categories, there are several possible variations, both in the dose rate and the placement of the radiation source. The dose rate can be low, medium, or high, or it can be delivered in pulses. Placement of the radioactive material may be interstitial, where it is inserted into the tumor, or contact, where it is placed right next to the tumor.
Brachytherapy treatment may be administered by placing a radiation source in the body temporarily, or the radiation source may be left at the site of the tumor permanently. Temporary treatment may be done in the hospital or on an outpatient basis, and the radiation may be administered for anywhere from minutes to days; these factors typically depend on the type and size of the cancer and the dose rate being given. During permanent brachytherapy treatment, small radioactive seeds are placed in or near the tumor and left there, where the amount of radiation they give off slowly decreases over time until it is almost nothing.
Different types of cancers typically require different dose rates of brachytherapy treatment. Oral cancers and sarcomas are often treated with a low-dose rate, or LDR, as is prostate cancer, which is often best addressed with permanent LDR seeds. Other cancers such as lung, breast, and cervical are better suited for temporary treatment with a high-dose rate, or HDR. Another option is a pulsed-dose rate, or PDR, where short bursts of radiation are applied to the tumor at measured intervals.
Another variation in brachytherapy treatment is where the source of radiation is placed in relation to the tumor. It may be placed directly within the tissue being targeted, a procedure known as interstitial brachytherapy. This technique is common for treatment of tumors in such locations as the prostate or breast. The other option is contact brachytherapy, where the radiation source is inserted in close proximity to the cancer. This may be achieved by placing it in a body cavity, a blood vessel, or tubular organ such as the trachea, or positioning it externally on the skin near the tumor.
