Radiotherapy Machine Downtime in Resource-Constrained Environments: A Quality Assurance-Oriented Analysis of BED/EQD2 Variations, Treatment Interruptions, and Patient Safety Concerns from the Standpoint of a Clinical Medical Physicist

Purpose: In low-resource healthcare systems like Bangladesh, radiotherapy machine downtimes frequently disrupt treatment continuity, compromise dose accuracy, and jeopardize patient outcomes. This study provides a detailed assessment of how unscheduled treatment interruptions impact dosimetry specifically deviations in Biological Effective Dose (BED) and Equivalent Dose in 2 Gy fractions (EQD2) treatment timelines, and patient safety. The evaluation is conducted from the operational viewpoint of clinical medical physicists. Methods: This retrospective observational study was carried out at a high-capacity oncology facility in Bangladesh over a 36-month period (January 2021-December 2023). Data were drawn from daily quality assurance records, machine downtime reports for linear accelerator and cobalt units, patient treatment calendars, and radiation oncology charts. BED and EQD2 deviations were modeled for three key cancer types head and neck, breast, and cervical—where extended treatment gaps occurred. Quantitative results were supported by qualitative data from real-time observations and logbook notes kept by medical physicists, providing insight into workflow interruptions and patient care challenges. Results: Among the 186 machine downtime incidents recorded, 34% led to treatment interruptions lasting more than 48 hours. Clinically meaningful BED and EQD2 deviations were noted, especially in head and neck cancer treatments where there was limited flexibility in fractionation. Extended overall treatment durations (OTT) were associated with reduced tumor control in selected cases. Additionally, patients often faced psychological strain and logistical issues such as travel problems and prolonged treatment periods, all of which undermined adherence and satisfaction. Conclusion: Machine downtimes in Bangladesh’s radiotherapy landscape present significant risks to treatment effectiveness and patient well-being. This study emphasizes the need for robust QA-based monitoring systems, flexible dose-adjustment strategies, and comprehensive national policies to reduce clinical disruptions. Ensuring both accurate dose delivery and patient-focused operational planning is essential to safeguard treatment standards in resource-constrained environments.