Program Information

Commissioning and Clinical Use of PC-ISO for Customized, 3D Printed, Gynecological Brachytherapy Applicators

J Cunha

J Cunha*, R Sethi , K Mellis , T Siauw , A Sudhyadhom , I Hsu , J Pouliot , UC San Francisco, San Francisco, CA

Presentations

WE-F-16A-1 Wednesday 2:45PM - 3:45PM Room: 16A

Purpose: (1) Evaluate the safety and radiation attenuation properties of PC-ISO, a bio-compatible, sterilizable 3D printing material by Stratasys, (2) establish a method for commissioning customized multi- and single-use 3D printed applicators, (3) report on use of customized vaginal cylinders used to treat a series of serous endometrial cancer patient.

Methods: A custom film dosimetry apparatus was designed to hold a Gafchromic radio film segment between two blocks of PC-ISO and 3D-printed using a Fortus 400mc (StrataSys). A dose plan was computed using 13 dwell positions at 2.5 mm spacing and normalized to 1500 cGy at 1 cm. Film exposure was compared to control tests in only air and only water. The average Hounsfield Unit (HU) was computed and used to verify water equivalency. For the clinical use cases, the physician specifies the dimensions and geometry of a custom applicator from which a CAD model is designed and printed.

Results: The doses measured from the PC-ISO Gafchromic film test were within 1% of the dose measured in only water between 1cm and 6cm from the channel. Doses increased 7-14% measured in only air. HU range was 11-43. The applicators were sterilized using the Sterrad system multiple times without damage. As of submission 3 unique cylinders have been designed, printed, and used in the clinic. A standardizable workflow for commissioning custom 3D printed applicators was codified and will be reported.

Conclusions: Quality assurance (QA) evaluation of the PC-ISO 3D-printing material showed that PC-ISO is a suitable material for a gynecological brachytherapy vaginal cylinder in a clinical setting. With the material commissioning completed, if the physician determines that a better treatment would result, a customized design is fabricated with limited additional QA necessary. Although this study was specific to PC-ISO, the same setup can be used to evaluate other 3D-printing materials.


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