A systems theory-based safety assessment of pre-treatment patient-specific quality assurance for intensity-modulated treatments in a single-vendor environment.

BACKGROUND AND PURPOSE: While patient-specific quality assurance (PSQA) has been integral to intensity-modulated treatments, its value is debated. A systems approach to safety is essential for understanding complex systems like radiation oncology but is often overlooked in PSQA research. This study aims to elucidate PSQA's fundamental value and identify opportunities for enhancing safety in intensity-modulated treatments. MATERIALS AND METHODS: First, causal scenarios that could lead to patient harm were identified using a prospective safety assessment technique developed for complex systems. Second, PSQA's ability to mitigate these scenarios was evaluated using standard stability and control principles. The analysis also included safeguards related to PSQA, such as daily linac QA, equipment commissioning, and equipment design. RESULTS: Ten causal scenarios were identified, highlighting well-known issues like flawed algorithms, data corruption, and hardware errors. Mitigation is achieved through advanced dose calculation and optimization algorithms, software and data integration, and preconfigured beam data, which improve decision-making and system state determination. Modern linac control systems enhance all aspects of system stability and control. Commissioning, daily linac QA, and PSQA are effective in enhancing the determination of system states only when feedback is non-overlapping and unambiguous. CONCLUSION: Given equipment improvement and related safeguards, the feedback generated from PSQA has diminished in value. To better complement other safeguards, PSQA should evolve to provide automated, unambiguous detection of any potential catastrophic treatment deviations prior to treatment. This evolution would allow physicists to focus on more critical aspects of patient care in radiation oncology.

Safety and Efficiency Analysis of Operational Decision-Making During Cone Beam Computed Tomography-Based Online Adaptive Radiation Therapy.

PURPOSE: Cone beam computed tomography (CBCT)-based online adaptive radiation therapy (ART) is especially beneficial for patients with large interfractional anatomic changes. However, treatment planning and review decisions need to be made at the treatment console in real-time and may be delegated to clinical staff whose conventional scope of practice does not include making such decisions. Therefore, implementation can create new safety risks and inefficiencies. The objective of this work is to systematically analyze the safety and efficiency implications of human decision-making during the treatment session for CBCT-based online ART. METHODS AND MATERIALS: The analysis was performed by applying the Systems-Theoretical Process Analysis technique and its extension for human decision-making. Four centers of different CBCT-based online ART practice models comprised the analysis team. RESULTS: The general radiation therapy control structure was refined to model the interactions between routine treatment delivery staff and in-person or remote support staff. The treatment delivery staff perform 6 key control actions. Eighteen undesirable states of those control actions were identified as affecting safety and/or efficiency. In turn, 97 hazardous clinical scenarios were identified, with the control action "prepare and position patient" having the least number of scenarios and "delineate/edit influencer and target structures" having the most. Five of these are specific to either in-person or remote support during the treatment session, and 12 arise from staff support in general. CONCLUSIONS: An optimally safe and efficient online ART program should require little to no support staff at the treatment console to reduce staff coordination. Uptraining of the staff already at the treatment console is needed to achieve this goal. Beyond the essential knowledge and skills such as contour editing and the selection of an optimal plan, uptraining should also target the specific cognitive biases identified in this work and the cognitive strategies to overcome these biases. Additionally, technological and organizational changes are necessary.

A system-based operational assessment of external beam radiotherapy.

PURPOSE: Advanced technologies have led to improvements in modern radiotherapy over the years. However, adoption of advanced technologies can present challenges to existing clinical operations and negatively impact safety. The purpose of this work is to perform an assessment of modern radiotherapy for the operational objectives of safety, efficiency, and financial viability. METHODS: This work focuses on external beam radiotherapy (EBRT). The operational assessment included department management, treatment planning, treatment delivery, and associated workflows for three equipment configurations of Ethos, Halcyon, and TrueBeam with the ARIA information system, Eclipse treatment planning, and IDENTIFY surface guidance. Systems-theoretic process analysis (STPA) was used to analyze the related workflows. Control actions, unsafe contexts of those control actions, and associated causal scenarios that can lead to unsafe radiation and non-radiation physical injury (safety objective), reduced treatment capacity (efficiency objective), and costs that exceed budget (financial viability objective) were identified. RESULTS: The number of control actions (and causal scenarios) were 18 (254), 18 (267), and 20 (267) for the equipment configurations of Halcyon, TrueBeam, and Ethos, respectively. The extent that safety, efficiency, and financial viability were impacted is similar across the different equipment configurations, but there were some noteworthy differences related to information transfer and workflow bottlenecks potentially impacting access to care. Seventy-five percent of the scenarios across all three configurations were related to safety. Overall, 29% of the scenarios impacted more than one operational objective and 48% were related to human decisions during the process of care. Planned or unplanned process changes were responsible for 8% of the causal scenarios. CONCLUSIONS: Broad-based clinical improvements may be realized by addressing causal scenarios that impact multiple objectives. Redesigning the roles and responsibilities of the clinical team and some aspects of the radiotherapy workflow may be helpful to fully realize the benefits of advanced technologies. Radiotherapy may benefit from additional tools to improve the consistency between decisions and actions when system or process changes occur.