Brachytherapy | Characteristics and Types

What are the characteristics of Brachytherapy?

• Can be used in combination with external beam radiotherapy and chemotherapy
• Extremely localized effect. The irradiation does not affect  the healthy tissues further away from the source.
• The radiation sources are placed in a protective capsule or a wire, which does not let the source move around, or get dissolved in the body fluids.
• This capsule can be removed later, or allowed to stay permanently.
• It retains its position even if the tumor moves or the patient changes the position.
• It is completed in lesser time than other RT techniques.
• Hence, it reduces the survival of cancer cells.
• This can be given on Out-patient basis, which is convenient for the patients.
• Has shown good patient compliance.

Brachytherapy seed implant (with Iodine-125)
image courtesy-isoaid.com

What are the sources?

• Sources used earlier were  naturally occurring isotopes, such as radium or radon.
• Now, usually artificially produced isotopes are used, for example cesium 137,iridium 198, and iodine 125.
• Treatment plans are prepared using radiographs or X-rays.
• CT-guided brachyhtherapy has been an area of research interest

What are the types of Brachytherapy according to dosage?
Low dose rate (LDR)

• Brachytherapy has been traditionally delivered over 3 to 4 days as an inpatient procedure at a low dose rate.
• Commonly used for oral cancer, cancer of oropharynx, prostate, sarcomas.

High dose rate (HDR) 

• Given using high-activity iridium sources.
• This is an outpatient procedure requiring only minimal anesthesia.
• Has given good results in elderly patients and patients having multiple medical problems.
• Good results have been reported in many cancers, including the head and neck,oesophagus, breast,cervix, endometrium, and prostate.

Medium dose rate (MDR) and Pulsed dose rate (PDR) are also used.

We will learn about brachytherapy: step-wise  procedure  in the next article.

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