Session Item

Brachytherapy has been successful in targeting the tumor while sparing surrounding normal tissues thanks to the basic principle of introducing the source of radiation directly into the tumor. Proper applicator/catheter placement is essential to optimal brachytherapy delivery. HDR dwell time optimization has permitted further customization of the treatment plan, but its impact is limited to what can be achieved with a given implant geometry and patient anatomy. Recently, new approaches have been attempted to further the customization of brachytherapy treatment plans, through (i) customization of applicators; (ii) enhanced customization of dose distribution; (iii) manipulation of the underlying anatomy. The status of the art for 3D printing of applicators will be covered, with a focus on future opportunities in the design of patient-specific applicators and an assessment of logistical and regulatory issues surrounding the medical use of this technology. Examples (e.g., custom applicator for intra-operative radiation treatments) will be discussed. A second novel approach to treatment plan customization is to maintain the basic implant geometry but utilize “modulated” brachytherapy optimization to permit preferential irradiation of the tissue on one side of the source instead of other. While this approach has historically been used in shielded applicator with little or no “modulation” of the shield during treatment, recent advances in rotating shield brachytherapy and other technological solutions have the potential of expanding the scope of shielded brachytherapy. Potential applications in prostate and gynecologic brachytherapy will be presented. Finally, custom modification of anatomy using spacer gels has been used to permit escalation of dose to the tumor while limiting the complication probability to the displaces organ. Examples in prostate and gynecologic brachytherapy will be presented.