Browsing by Author "Njeh, Christopher F."

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    Assessing Radiology and Radiation Therapy Needs for Cancer Care in Low-and-Middle-Income Countries: Insight From a Global Survey of Departmental and Institutional Leaders
    (Elsevier, 2024-08-29) Parker, Stephanie A.; Weygand, Joseph; Bernat, Beata Gontova; Jackson, Amanda M.; Mawlawi, Osama; Barreto, Izabella; Hao, Yao; Khan, Rao; Yorke, Afua A.; Swanson, William; Huq, Mohammed Saiful; Lief, Eugene; Biancia, Cesar Della; Njeh, Christopher F.; Al-Basheer, Ahmad; Chau, Oi Wai; Avery, Stephen; Ngwa, Wilfred; Sandwall, Peter A.; Radiation Oncology, School of Medicine
    Purpose: The global cancer burden and mortality rates are increasing, with significant disparities in access to care in low- and middle-income countries (LMICs). This study aimed to identify radiology and radiation therapy needs in LMICs from the perspective of departmental and institutional leaders. Methods and materials: A survey was developed and conducted by the American Association of Physicists in Medicine Global Needs Assessment Committee and the American Association of Physicists in Medicine International Council. The survey, organized into 5 sections (Introduction, Infrastructure Needs, Education Needs, Research Needs, and General Information), was open to respondents from March 1, to August 16, 2022. Results: A total of 175 responses were received from 6 global regions: Africa (31.4%), the Americas (17.7%), the Eastern Mediterranean (14.3%), Europe (9.1%), Southeast Asia (23.4%), and the Western Pacific (4.0%). The greatest reported need was for new or updated equipment, particularly positron emission tomography/computed tomography imaging technology. There was also a high demand for clinical and equipment training. Approximately 25% of institutions reported a lack of radiology-based cancer screening programs because of high health care costs and a shortage of specialized equipment. Many institutions that expressed interest in research face funding and grant challenges. Conclusions: The findings highlight critical areas where organizations can support LMICs in enhancing radiology and radiation therapy services to mitigate the growing cancer burden.
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    Patient specific quality assurance of volumetric modulated arc therapy of synchronous bilateral breast cancer
    (Elsevier, 2024) Djoumessi Zamo, Francis C.; Njeh, Christopher F.; Colliaux, Anthony; Blot-Lafond, Valérie; Moyo, M. Ndontchueng; Radiation Oncology, School of Medicine
    Synchronous bilateral breast cancers (SBBC) present a considerable issue in external beam radiotherapy because of large fields size and large target volumes. Mono-isocentric volumetric modulated arc therapy (VMAT) appears as an appropriate irradiation technique for these types of tumors. The aim of this study was to demonstrate the utility of a 3D DVH pretreatment quality assurance program in VMAT of SBBC cases. Twenty SBBC patients who underwent radiation therapy in our department were retrospectively enrolled in this study. Fifteen patients were treated exclusively to the mammary glands. Five patients benefited from a dose boost on the tumor bed (60Gy). Nine patients were irradiated on the supraclavicular nodes (50Gy). This dose was delivered in 25 fractions and integrated boost was used when appropriate. Depending on the complexity of the treatment plans; 2 or 4 arcs VMAT plans were used in a mono-isocentric technique. The patient specific quality assurance (PSQA) was evaluated using COMPASS measured data, COMPASS reconstructed (CR) and COMPASS computed (CC) dose compared to treatment planning system (TPS) dose. Clinical evaluation was based on DVH metrics for target volumes and organ at risks. The maximum average dose deviation between TPS, CC, and CR was below 3%. The paired t-test between TPS, CC, and CR shows a strong agreement (p < 0.001). The 3DVH dose distribution comparison between TPS and COMPASS were also performed with good gamma score for global analysis. COMPASS was successfully evaluated as a 3DVH pretreatment system for SBBC despite the large fields size and complex target volumes. It allows the verification of the plan in 3D patient anatomy and the evaluation of dose discrepancies.
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    VMAT partial arc technique decreases dose to organs at risk in whole pelvic radiotherapy for prostate cancer when compared to full arc VMAT and IMRT
    (Elsevier, 2023-03) Bartlett, Gregory K.; Njeh, Christopher F.; Huang, Ke C.; DesRosiers, Colleen; Guo, Gordon; Radiation Oncology, School of Medicine
    Whole pelvic radiotherapy (WPRT) can sterilize microscopic lymph node metastases in treatment of prostate cancer. WPRT, compared to prostate only radiotherapy (PORT), is associated with increased acute gastrointestinal, and hematological toxicities. To further explore minimizing normal tissue toxicities associated with WPRT in definitive IMRT for prostate cancer, this planning study compared dosimetric differences between static 9-field-IMRT, full arc VMAT, and mixed partial-full arc VMAT techniques. In this retrospective study, 12 prostate cancer patients who met the criteria for WPRT were randomly selected for this study. The initial volume, PTV46, included the prostate, seminal vesicles, and pelvic nodes with margin and was prescribed to 4600 cGy. The cone-down volume, PTV78, included the prostate and proximal seminal vesicles with margin to a total dose of 7800 cGy. For each CT image set, 3 plans were generated for each of the PTVs: an IMRT plan, a full arc (FA) VMAT plan, and a mixed partial-full arc (PFA) VMAT plan, using 6MV photons energy. According to RTOG protocols none of the plans had a major Conformity Index (CI) violation by any of the 3 planning techniques. PFA plan had the best mean CI index of 1.00 and significantly better than IMRT ( p = 0.03) and FA ( p = 0.007). For equivalent PTV coverage, the average composite gradient index of the PFA plans was better than the IMRT and the FA plans with values 1.92, 2.03, and 2.01 respectively. The difference was statistically significant between PFA/IMRT and PFA/FA, with p - values of < 0.001. The IMRT plans and the PFA plans provided very similar doses to the rectum, bladder, sigmoid colon, and femoral heads, which were lower than the dose in the FA plans. There was a significant decrease in the mean dose to the rectum from 4524 cGy with the FA to 4182 cGy with the PFA and 4091 cGy with IMRT ( p < 0.001). The percent of rectum receiving 4000 cGy was also the highest with FA at 66.1% compared to 49.9% (PFA) and 47.5% (IMRT). There was a significant decrease in the mean dose to the bladder from 3922 cGy (FA) to 3551 cGy (PFA) and 3612 cGy (IMRT) ( p < 0.001). The percent of bladder receiving 4000 cGy was also the highest with FA at 45.4% compared to 36.6% (PFA) and 37.4% (IMRT). The average mean dose to the sigmoid colon decreased from 4177 cGy (FA) to 3893 cGy (PFA) and 3819 cGy (IMRT). The average mean dose to the femoral heads decreased from 2091 cGy (FA) to 2026 cGy (PFA) and 1987 cGy (IMRT). Considering the improvement in plan quality indices recorded in this study including the dose gradient and the dose to organs at risk, mixed partial-full arc plans may be the preferred VMAT treatment technique over full arc plans for prostate cancer treatments that include nodal volumes.