Abstract 109: A Longitudinal Telehealth Curriculum for Radiation Oncology Centers in Low and Middle-Income Countries Transitioning from 2D to 3D External Beam Radiation Therapy

Purpose: The transition from 2-dimensional (2D) to 3-dimensional (3D) external beam radiation therapy (EBRT) can dramatically improve the quality of radiotherapy in low and middle-income countries (LMICs); however, many cancer centers in LMICs lack training support to effectively make this transition. Remote training is a low-cost, accessible option to bridge this gap, and we sought to evaluate the efficacy of such a program.

Methods: The nonprofit Rayos Contra Cancer identified 9 LMIC operational cancer centers in the Middle East and Northern Africa that had recently acquired technology to transition from 2D to 3D EBRT. Baseline information for each center was collected electronically, then a team of EBRT content experts developed a 12-week, 25-session continuing medical education curriculum. Each session invited live participation using Zoom video communications and lasted 1 - 2 hours. Participants were administered a Likert scale (1-5) confidence evaluation on 13 foundational topics in 3D EBRT and a 49-point knowledge-based multiple-choice examination pre- and post- curriculum. Anonymous feedback with 1-5 satisfaction scores for each session was solicited midway and at the conclusion of the curriculum. Training was provided for free.

Results: Among centers, 260 participants enrolled in training, including 39 medical physicists, 36 radiation oncologists, 54 radiation therapists, 15 dosimetrists, and 116 in training or other roles. Pre- and post-curriculum average examination scores were 22.95/49 (53.4%, N = 171) and 30.76/49 (62.8%, N=87), respectively. Pre- and post-curriculum confidence evaluation showed an average of 1.4/5 (27.7%, N=260) and 3.86 (77.2%, N=74) confidence among 13 topics. Satisfaction surveys (halfway N=51, end N=48) showed high satisfaction with helpfulness (4.3/5) enjoyableness (4.2/5), and well-preparedness (4.4/5) of sessions.

Conclusion: Satisfaction, confidence, and knowledge domains were all measured with favorable results. This innovative low-cost telehealth model for EBRT training is a promising vehicle for advancing cancer care in LMICs by providing educational support.

Citation Format: Fei Yang, Raymond Carter, Soha Ahmed, Tia Plautz, Piotr Dubrowski, Shada Wadi-Ramahi, Sarah Ashmeg, Frank Ascoli, Daniel Wakefield, Justus Adamson, Benjamin Li. A Longitudinal Telehealth Curriculum for Radiation Oncology Centers in Low and Middle-Income Countries Transitioning from 2D to 3D External Beam Radiation Therapy [abstract]. In: Proceedings of the 9th Annual Symposium on Global Cancer Research; Global Cancer Research and Control: Looking Back and Charting a Path Forward; 2021 Mar 10-11. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2021;30(7 Suppl):Abstract nr 109.

Novel scintillation detector design and performance for proton radiography and computed tomography

PURPOSE

Proton computed tomography (pCT) will enable accurate prediction of proton and ion range in a patient while providing the benefit of lower radiation exposure than in x-ray CT. The accuracy of the range prediction is essential for treatment planning in proton or ion therapy and depends upon the detector used to evaluate the water-equivalent path length (WEPL) of a proton passing through the object. A novel approach is presented for an inexpensive WEPL detector for pCT and proton radiography.

METHODS

A novel multistage detector with an aperture of 10 × 37.5 cm was designed to optimize the accuracy of the WEPL measurements while simplifying detector construction and the performance requirements of its components. The design of the five-stage detector was optimized through simulations based on the geant4 detector simulation toolkit, and the fabricated prototype was calibrated in water-equivalent millimeters with 200 MeV protons in the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center. A special polystyrene step phantom was designed and built to speed up and simplify the calibration procedure. The calibrated five-stage detector was tested in the 200 MeV proton beam as part of the pCT head scanner, using a water phantom and polystyrene slabs to verify the WEPL reconstruction accuracy.

RESULTS

The beam-test results demonstrated excellent performance of the new detector, in good agreement with the simulation results. The WEPL measurement accuracy is about 3.0 mm per proton in the 0-260 mm WEPL range required for a pCT head scan with a 200 MeV proton beam.

CONCLUSIONS

The new multistage design approach to WEPL measurements for proton CT and radiography has been prototyped and tested. The test results show that the design is competitive with much more expensive calorimeter and range-counter designs.

200 MeV proton radiography studies with a hand phantom using a prototype proton CT scanner

Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton computed tomography (CT) scanner prototype, which was installed on the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center. It was found that while both radiographs displayed anatomical details of the hand phantom, the energy-loss radiograph had a noticeably higher resolution. Nonetheless, scattering radiography may yield more contrast between soft and bone tissue than energy-loss radiography, however, this requires further study. This study contributes to the optimization of the performance of the next-generation of clinical proton CT scanners. Furthermore, it demonstrates the potential of proton imaging (proton radiography and CT), which is now within reach of becoming available as a new, potentially low-dose medical imaging modality.