Anal or Rectal brachytherapy are procedures involving use of radiation in a very selective way to target affected areas while sparing unaffected tissue unnecessary radiation exposure. The radiation is delivered using a piece of equipment called an afterloader, which contains a high dose radiation source placed at the tip of a wire. A brachytherapy applicator, in this case the AR, is placed into the rectum and inflated. The inflation of the device has 2 functions.
The first function is to expand the rectum which will allow for the healthy tissue to be distanced from the tumor site. The second function is to deploy the treatment catheters. The AR applicator has 8 catheters which will allow clinicians to decide where the radiation will be targeted and which catheters will best allow for the best radiation treatment plan.
Once a radiation treatment plan is calculated the applicator is connected to the afterloader. The afterloader will deliver the radiation source into the applicator as directed by the treatment plan. The source will travel through the catheters of the applicator to specific locations and where it will stop and remain for specific periods of time. The locations of these stops, combined with the length and number of these stops will determine how the radiation is delivered.
This portion of treatment lasts only a few minutes. Once the radiation is delivered the applicator is removed. The Physician will determine how many treatments will be necessary (3 treatments is a commonly used number) and if it will be in combination with chemotherapy or External Beam Radiation Therapy.
The Ancer Medical AR™ is a first of its kind, disposable brachytherapy applicator designed specifically for the treatment of anal and rectal cancers. The AR™ combines unique innovations with proven brachytherapy technology to bring a new Ancer to the question of anorectal cancer treatment.AR™ Unique Device Dimensions
- 2.3 cm uninflated insertion diameter for ease of placement
- 8-10cm effective treatment zone allows treatment of entire rectum without repositioning
Dual Balloon Construction
- 3.5-4cm inner balloon inflated diameter creates consistent, repeatable source catheter positioning
- Outer balloon creates protective spacing between source catheters and tissue, fully distending the rectum ensuring repeatable tumor coverage
- Radio-opaque contrast markers visible under X-ray, CT and MRI ensure consistent device placement.
- Contrast Markers and handle markings ensure depth and rotational consistency
- Inner balloon design ensures precise, consistent source catheter positioning
- Consistent fill volumes ensure repeatable tissue spacing.
- Compliant outer balloon ensures optimal tissue separation and conformity around tumors
- Non-compliant inner balloon supports 8 evenly spaced treatment catheters ensuring optimal positioning for surface dose control
- Device construction and materials designed to take full advantage of MRI guided brachytherapy
The AR applicator allows the prescription dose to envelop the tumor and the delivery of a very high dose to the tumor surface, all of this while sparing the healthy rectum and anal muscle, in a way that could not be achieved with external beam therapy.”
Comments and images courtesy of Karyn A. Goodman, MD and
Gil’ad N. Cohen, MS Memorial Sloan Kettering Cancer Center New York, NY