Brachytherapy

Dr. Janet Nettleton is well known within the medical community for her ability to make quality decisions in which types of cancer treatments are appropriate for varying patients and their cancer types. One of the options that Dr. Nettleton will pursue is a form of radiation called LDR (Low Dose Radiation) Brachytherapy. Dr. Janet Nettleton performs these procedures at Sierra Vista Regional and has been involved with this technology for many years. Her experience in this technology is unmatched, and should Dr. Nettleton decide that LDR Brachytherapy is the best course of action; rest assured that you are in the best hands. Read below for more information about LDR Brachytherapy, and what it can do.

What is Brachytherapy?

Brachytherapy dates back to 1901 (shortly after the discovery of radioactivity by Becquerel in 1896) when Pierre Curie suggested to Henri-Alexandre Danlos that a radioactive source could be inserted into a tumour.It was found that the radiation caused the tumour to shrink.Independently, Alexander Graham Bell also suggested the use of radiation in this way.In the early twentieth century, techniques for the application of brachytherapy were pioneered at the Curie institute in Paris by Danlos and at St Luke's and Memorial Hospital in New York by Robert Abbe.

Following initial interest in brachytherapy in Europe and the US, its use declined in the middle of the twentieth century due to the problem of radiation exposure to operators from the manual application of the radioactive sources.

However, the development of remote afterloading systems, which allow the radiation to be delivered from a shielded safe, and the use of new radioactive sources in the 1950s and 1960s, reduced the risk of unnecessary radiation exposure to the operator and patients.This, together with more recent advancements in three dimensional imaging modalities, computerised treatment planning systems and delivery equipment has made brachytherapy a safe and effective treatment for many types of cancer today.

  • Low-dose rate(LDR) brachytherapy involves implanting radiation sources that emit radiation at a rate of up to 2 Gy.hr-1.LDR brachytherapy is commonly used for cancers of the oral cavity,oropharynx,sarcomasand prostate cancer.

Source placement

The two main types of brachytherapy treatment in terms of the placement of the radioactive source are interstitial and contact.

  • In the case of interstitial brachytherapy, the sources are placed directly in the target tissue of the affected site, such as the prostate or breast.
  • Contact brachytherapy involves placement of the radiation source in a space next to the target tissue.This space may be a body cavity (intracavitary brachytherapy) such as the cervix, uterus or vagina; a body lumen (intraluminal brachytherapy) such as the trachea or oesophagus; or externally (surface brachytherapy) such as the skin.A radiation source can also be placed in blood vessels (intravascular brachytherapy) for the treatment of coronary in-stent restenosis.

Duration of dose delivery

Permanent brachytherapy is often performed for prostate cancer using "seeds" - small radioactive rods implanted directly into the tumour.

The placement of radiation sources in the target area can be temporary or permanent.

  • Temporary brachytherapy involves placement of radiation sources for a set duration (usually a number of minutes or hours) before being withdrawn.The specific treatment duration will depend on many different factors, including the required rate of dose delivery and the type, size and location of the cancer. In LDR and PDR brachytherapy, the source typically stays in place up to 24 hours before being removed, while in HDR brachytherapy this time is typically a few minutes.
  • Permanent brachytherapy, also known as seed implantation, involves placing small LDR radioactive seeds or pellets (about the size of a grain of rice) in the tumour or treatment site and leaving them there permanently to gradually decay. Over a period of weeks or months, the level of radiation emitted by the sources will decline to almost zero. The inactive seeds then remain in the treatment site with no lasting effect. Permanent brachytherapy is most commonly used in the treatment of prostate cancer.