Using Varian’s Eclipse Scripting API to Calculate, Add, and Report Biologically Equivalent Doses for Gynecological Brachytherapy and External Beam Radiation Therapy Patients

Abstract

Standard procedure adopted by our institution involves generating post treatment reports for all gynecological patients receiving brachytherapy. These reports tabulate physical doses, biological effective doses (BED), and biological equivalent doses (EQD2) for two Gray fractionation schemes to the high risk clinical target volume (HRCTV), intermediate risk clinical target volume (IRCTV), bladder, rectum, sigmoid, bowel, and vagina. All doses are reported following ABS guidelines for cervical cancers. These metrics were previously read individually from the dose volume histogram and dose statistics tab and charted one by one in a spreadsheet which was uploaded to the patient’s electronic chart. To streamline data collection and metric calculation for reporting after treatment and to better inform on cumulative doses for treatments in progress, an integrated script within Varian’s Brachytherapy Planning (Varian Medical Systems, Palo Alto, CA) was developed using the Eclipse Scripting Application Programming Interface (ESAPI). ESAPI was used in conjunction with Microsoft Virtual Studio (Microsoft Corporation, Redmond, WA) to write a script that can be called within the Eclipse External Beam Planning or Brachytherapy Planning user interfaces. The script queries all external beam and brachytherapy plans within an opened course to return the physical dose and calculate the biological effective and biological equivalent doses for seven pre-determined structures. The values returned are consistent with the reporting values used in the ABS guidelines for cervical cancers. While all plans within a course are included in the totals, the option to exclude specific plans or add in additional dose from external beam radiation therapy can be added for improved usability depending on the clinic’s desired use and implementation of the script. The development of an integrated script within the treatment planning interface allows for efficient dose recording for brachytherapy patients. In addition, the ease of use also allows for tracking dosimetric progress during the boosted brachytherapy course of treatment. This allows for adapting the brachytherapy plans to meet the desired objectives and dose constraints. Use of the script allows for an overall more streamlined approach to our clinical procedures of reporting doses in gynecological brachytherapy patients while minimizing the potential for errors in using multistep approach of entering metrics by hand. Adaptations and implementations of the script will be extended to external beam radiation therapy gynecological clinical protocols in place at our institution.