RESUMEN
PURPOSE: High dose-rate (HDR) brachytherapy is integral for the treatment of numerous cancers. Preclinical studies involving HDR brachytherapy are limited. We aimed to describe a novel platform allowing multi-modality studies with clinical HDR brachytherapy and external beam irradiators, establish baseline dosimetry standard of a preclinical orthovoltage irradiator, to determine accurate dosimetric methods. METHODS: A dosimetric assessment of a commercial preclinical irradiator was performed establishing the baseline dosimetry goals for clinical irradiators. A 3D printed platform was then constructed with 14 brachytherapy channels at 1cm spacing to accommodate a standard tissue culture plate at a source-to-cell distance (SCD) of 1 cm or 0.4 cm. 4-Gy CT-based treatment plans were created in clinical treatment planning software and delivered to 96-well tissue culture plates using an Ir192 source or a clinical linear accelerator. Standard calculation models for HDR brachytherapy and external beam were compared to corresponding deterministic model-based dose calculation algorithms (MBDCAs). Agreement between predicted and measured dose was assessed with 2D-gamma passing rates to determine the best planning methodology. RESULTS: Mean (±standard deviation) and median dose measured across the plate for the preclinical irradiator was 423.7 ± 8.5 cGy and 430.0 cGy. Mean percentage differences between standard and MBDCA dose calculations were 9.4% (HDR, 1 cm SCD), 0.43% (HDR, 0.4 cm SCD), and 2.4% (EBRT). Predicted and measured dose agreement was highest for MBDCAs for all modalities. CONCLUSION: A 3D-printed tissue culture platform can be used for multi-modality irradiation studies with great accuracy. This tool will facilitate preclinical studies to reveal biologic differences between clinically relevant radiation modalities.
RESUMEN
PURPOSE: Radiopharmaceutical therapy (RPT) is a rapidly growing treatment modality. Though uncommon, patients may experience complications during their RPT treatment, which may trigger a rapid response from the hospital team. However, members of this team are typically not familiar with precautions for radiation safety. During these events, it is important to prioritize the patient's health over all else. There are some practices that can help minimize the risk of radiation contamination spread and exposure to staff while tending to the patient. METHODS AND MATERIALS: We formed a team to develop a standard protocol for handling patient emergencies during RPT treatment. This team consisted of an authorized user, radiation safety officer, medical physicist, nurse, RPT administration staff, and a quality/safety coordinator. The focus for developing this standardized protocol for RPT patient emergencies was 3-fold: (1) stabilize the patient; (2) reduce radiation exposure to staff; and (3) limit the spread of radiation contamination. RESULTS: We modified our hospital's existing rapid response protocol to account for the additional staff and tasks needed to accomplish all 3 of these goals. Each team member was assigned specific responsibilities, which include serving as a gatekeeper to restrict traffic, managing the crash cart, performing chest compressions, timing chest compressions, documenting the situation, and monitoring/managing radiation safety in the area. We developed a small, easy-to-read card for rapid response staff to read while they are en route to the area so they can be aware of and prepare for the unique circumstances that RPT treatments present. CONCLUSIONS: Though rapid response events with RPT patients are uncommon, it is important to have a standardized protocol for how to handle these situations beforehand rather than improvise in the moment. We have provided an example of how our team adapted our hospital's current rapid response protocol to accommodate RPT patients.