Surface Brachytherapy applicator

Custom-fit and optimized catheter trajectories keep a consistent SSD even over the most complex anatomy.

High Dose Rate (HDR) surface brachytherapy is a technique used to treat various types of skin lesions including basal and squamous cell carcinoma. 3D Bolus offers a patient specific alternative to the traditional practice of treating skin cancer using HDR brachytherapy. Traditional applicators are generic, coming in either circular (Leipzig) or square (Freiburg Flap) geometries. With Freiburg Flaps, it is very difficult to conform the applicator to irregular locations on the body, such as the face or scalp. 3D Bolus software allows the user to create a structure of uniform thickness within the treatment planning system that follows the contours of each individual patient. Our custom algorithm generates potential catheter positions within the structure itself at a uniform distance from source to the surface of the patient. The software then performs a subtraction operator to create hollow trajectories to allow the free movement of the radioactive source through the applicator. The catheter tunnels are printed directly within the applicator itself, eliminating the need to drill in tunnels post print. The 3D printed applicator, since it was designed from the patients CT scan, fits to the unique curves of each patient.

3D Bolus software allows the user to see the potential dose distribution before the piece is printed and
imported back into the TPS. If the dose distribution does not conform to the treatment area as well as
prescribed, individual catheter trajectories may be manually adjusted to fine tune the dose to a more
acceptable distribution. For example, the standard source to surface distance is 5 mm. The user may
wish for the third catheter to be located 6 mm from the surface to decrease a potential hot spot of
radiation and see the resulting distribution in real time.

3D Bolus software allows the user to generate this structure and export it as an STL file which is
compatible with all standard 3D printers on the market today. The user can print the applicator using
whichever filament they wish. The catheter tunnels are printed directly within the applicator itself,
eliminating the need to drill in tunnels post print. The 3D printed applicator, since it was designed from
the patients CT scan, fits to the unique curves of each patient. After the applicator is finished printing,
the radiation therapist will insert catheters (6-French after-loading catheters) into the tunnels
constructed by 3D Bolus software. These catheters will be hooked up to the after-loading machine at
the time of treatment to allow the source to travel to each dwell position to deliver dose. Once daily
treatment is completed, the applicator can be sterilized in any standard alcohol solution to prepare for
the next fraction of treatment.

Key benefits of 3D Bolus’ Surface Brachytherapy Applicators

  • Patient specific alternative to the traditional practice of treating skin cancer using HDR brachytherapy
  • Replaces the need for expensive circular (Leipzig) or square (Freiburg Flap)
  • Allows the user to create a structure of uniform thickness within the treatment planning system that follows the contours of each individual patient
  • Custom algorithm generates potential catheter positions within the structure itself at a uniform distance from source to the surface of the patient then creates hollow trajectories to allow the free movement of the radioactive source through the applicator
  • Allows the user to see the potential dose distribution before the piece is printed and imported back into the TPS