Risk factors for radiotherapy incidents and impact of an online electronic reporting system

Impact through versatility: Patterns of in vivo dosimetry utilization with TLD across a large multi-site radiotherapy department

The complexity of modern radiotherapy treatment pathways necessitate input from different professions to ensure treatment is delivered safely and as planned. In vivo dosimetry is one method of treatment verification providing the opportunity for both in-field verification or out-of-field measurements. It was the aim of this work to review the impact of an in vivo dosimetry programme with t.he view to justify resources and assist in developing a plan for equipment acquisition. Results of 310 (approximately 2 per 1000 treatment fractions) in vivo measurements were reviewed over a two-year time span. The in vivo dosimetry programme using thermoluminescence (TLD) chips was able to detect three significant treatment errors, amongst some 13 000 patients treated. These errors would likely to have been undetected through other quality assurance measures. Increasing demands in workload were found to be associated with commissioning of new equipment and techniques. A skilled operator with knowledge of TLD physics, treatment planning system (TPS) dose calculation algorithms and radiation transport proved to be essential for appropriate interpretation of TLD results particularly in complex radiation delivery scenarios. TLD continues to play a large role in patient safety and quality assurance at our institution.

Using a daily monitoring system to reduce treatment position override rates in external beam radiation therapy

PURPOSE/OBJECTIVES

To report our 7-year experience with a daily monitoring system to significantly reduce couch position overrides and errors in patient treatment positioning.

MATERIALS AND METHODS

Treatment couch position override data were extracted from a radiation oncology-specific electronic medical record system from 2012 to 2018. During this period, we took several actions to reduce couch position overrides, including reducing the number of tolerance tables from 18 to 6, tightening tolerance limits, enforcing time outs, documenting reasons for overrides, and timely reviewing of overrides made from previous treatment day. The tolerance tables included treatment categories for head and neck (HN) (with/without cone beam CT [CBCT]), body (with/without CBCT), stereotactic body radiotherapy (SBRT), and clinical setup for electron beams. For the same time period, we also reported treatment positioning-related incidents that were recorded in our departmental incident report system. To verify our tolerance limits, we further examined couch shifts after daily kilovoltage CBCT (kV-CBCT) for the patients treated from 2018 to 2021.

RESULTS

From 2012 to 2018, the override rate decreased from 11.2% to 1.6%/year, whereas the number of fractions treated in the department increased by 23%. The annual patient positioning error rate was also reduced from 0.019% in 2012, to 0.004% in 2017 and 0% in 2018. For patients treated under daily kV-CBCT guidance from 2018 to 2021, the applied couch shifts after imaging registration that exceeded the tolerance limits were low, <1% for HN, <1.2% for body, and <2.6% for SBRT.

CONCLUSIONS

The daily monitoring system, which enables a timely review of overrides, significantly reduced the number of treatment couch position overrides and ultimately resulted in a decrease in treatment positioning errors. For patients treated with daily kV-CBCT guidance, couch position shifts after CBCT image guidance demonstrated a low rate of exceeding the set tolerance.

Quality management in radiotherapy treatment delivery

Radiation Oncology continues to rely on accurate delivery of radiation, in particular where patients can benefit from more modulated and hypofractioned treatments that can deliver higher dose to the target while optimising dose to normal structures. These deliveries are more complex, and the treatment units are more computerised, leading to a re-evaluation of quality assurance (QA) to test a larger range of options with more stringent criteria without becoming too time and resource consuming. This review explores how modern approaches of risk management and automation can be used to develop and maintain an effective and efficient QA programme. It considers various tools to control and guide radiation delivery including image guidance and motion management. Links with typical maintenance and repair activities are discussed, as well as patient-specific quality control activities. It is demonstrated that a quality management programme applied to treatment delivery can have an impact on individual patients but also on the quality of treatment techniques and future planning. Developing and customising a QA programme for treatment delivery is an important part of radiotherapy. Using modern multidisciplinary approaches can make this also a useful tool for department management.

Impact of technological and departmental changes on incident rates in radiation oncology over a seventeen-year period

INTRODUCTION

Advancements in technology and processes are designed to bring improvement. However, this is often achieved in parallel with increases in complexity, simultaneously presenting opportunities for new types of errors. This study aims to contextualise the impact of internal departmental changes upon radiation incidents and near misses recorded.

METHODS

A timeline of events and a comprehensive incident categorisation system were applied to all radiation incidents and near misses recorded at the Princess Alexandra Hospital Radiation Oncology department from 2003 to 2019, inclusive. Descriptive statistics were performed to identify the type and number of incidents reported during the time period in relation to potential changes within the department, with a focus on the implementation of an electronic environment.

RESULTS

Over the seventeen-year period, 157 incidents and 76 near misses were reported. The majority of incidents were classified as 'procedural' (78%), with 'treatment' being both the highest point of error and point of detection (49% and 85%, respectively). The largest number of incidents and near misses were reported in 2018 (n = 39) which was also a year that experienced the largest number of departmental changes (n = 16), including the move to a completely electronic planning process.

CONCLUSIONS

Changes within the department were followed by an increasing number of reported incidents. Proactive measures should be undertaken prior to the implementation of major changes within the department to aid in the minimisation of incident occurrence.

The journey towards safer radiotherapy: are we on a road to nowhere?

Background:

Harnessing available knowledge and learning from our errors are prerequisites of delivering on the challenge of improving patient safety. Towards Safer Radiotherapy, published in 2008, was a response from the UK’s (UK) radiotherapy community to concerns arising from high profile errors. The report was a driver for the development of a national reporting and learning system for radiotherapy.

Materials and methods:

A literature review was conducted covering the years from 2009 to 2020. Search terms used were radiotherapy errors, patient safety, incident learning, human factors and trend analysis. A total of 10 papers reported recommendations or implementation of changes to service delivery models following systematic error analysis. None of these were from UK service providers.

Conclusions:

Twelve years on from the publication of Towards Safer Radiotherapy, there is little evidence of impact on safety culture within the UK radiotherapy community. Although the UK has a large radiotherapy error dataset, there remain unanswered questions about the impact on the safety culture in radiotherapy.

[A Human Factors Study Using VTA for Incident Cases in Radiotherapy]

In recent years, workload has increased with higher precision of radiotherapy. Although both efficiency and thoroughness of treatment are crucial, in such conditions, human error is easy to occur. In this study, five incident cases that occurred in four facilities were studied and analyzed from the viewpoint of human factors that contribute to errors using variation tree analysis. We also analyzed resilience (the ability to return to one's original state even if the system deviates from a stable state), which has attracted attention in recent safety research. There were potential factors represented by patient factors in all cases. These factors caused deviations from standard operations, and incidents occurred due to unfamiliar situations and operations. Furthermore, in four of the five cases, the cause of the incident was a resilience action or judgment that was deemed to have required "some sort of ingenuity or adjustment." It was found that human error occurred due to multiple simultaneous occurrences of potential factors, i.e., patient and human factors such as high workload, impatience, and work interruptions. A reduction in human errors can be achieved by avoiding time pressure and multitasking, creating work environment and working conditions that make resilience work well, revising ambiguous rules and procedures, and promoting standardized working methods.

Technical Note: Assessing the performance of monthly CBCT image quality QA

PURPOSE

To assess the performance of routine cone-beam computed tomography (CBCT) quality assurance (QA) at predicting and diagnosing clinically recognizable linac CBCT image quality issues.

METHODS

Monthly automated linac CBCT image quality QA data were acquired on eight Varian linacs (Varian Medical Systems, Palo Alto, CA) using the CATPHAN 500 series phantom (The Phantom Laboratory, Inc., Greenwich, NY) and Total QA software (Image Owl, Inc., Greenwich, NY) over 34 months between July 2014 and May 2017. For each linac, the following image quality metrics were acquired: geometric distortion, spatial resolution, Hounsfield Unit (HU) constancy, uniformity, and noise. Quality control (QC) limits were determined by American Association of Physicists in Medicine (AAPM) expert consensus documents Task Group (TG-142 and TG-179) and the manufacturer acceptance testing procedure. Clinically recognizable CBCT issues were extracted from the in-house incident learning system (ILS) and service reports. The sensitivity and specificity of CATPHAN QA at predicting clinically recognizable image quality issues was investigated. Sensitivity was defined as the percentage of clinically recognizable CBCT image quality issues that followed a failing CATPHAN QA. Quality assurance results are categorized as failing if one or more image quality metrics are outside the QC limits. The specificity of CATPHAN QA was defined as one minus the fraction of failing CATPHAN QA results that did not have a clinically recognizable CBCT image quality issue in the subsequent month. Receiver operating characteristic (ROC) curves were generated for each image quality metric by plotting the true positive rate (TPR) against the false-positive rate (FPR).

RESULTS

Over the study period, 18 image quality issues were discovered by clinicians while using CBCT to set up the patient and five were reported prior to x-ray tube repair. The incidents ranged from ring artifacts to uniformity problems. The sensitivity of the TG-142/179 limits was 17% (four of the prior monthly QC tests detected a clinically recognizable image quality issue). The area under the curve (AUC) calculated for each image quality metric ROC curve was: 0.85 for uniformity, 0.66 for spatial resolution, 0.51 for geometric distortion, 0.56 for noise, 0.73 for HU constancy, and 0.59 for contrast resolution.

CONCLUSION

Automated monthly QA is not a good predictor of CBCT image quality issues. Of the available metrics, uniformity has the best predictive performance, but still has a high FPR and low sensitivity. The poor performance of CATPHAN QA as a predictor of image quality problems is partially due to its reliance on region-of-interest (ROI) based algorithms and a lack of a global algorithm such as correlation. The manner in which image quality issues occur (trending toward failure or random) is still not known and should be studied further. CBCT image quality QA should be adapted based on how CBCT is used clinically.

How safe is radiotherapy practice in India: perceptions and practical experiences among the workers of radiotherapy facilities in North East, India?

Purpose

The aim of this study was to understand how the regulatory requirements for functioning radiotherapy practices in India to control risk were conceptualised, perceived and applied accordingly in the radiotherapy facilities. It further examined how the social factors influenced the decision-making process for implementing regulatory requirements in the radiotherapy facilities.

Material and method

This study was carried out in nine radiotherapy facilities located in the northeastern Indian states of Manipur, Assam, Meghalaya, Tripura and Mizoram. The study adopted both the semi-structured and in-depth questionnaire, developed on the basis of multidisciplinary fields.

Result

The study found that the facilities in the northeastern regions were commissioned in line with the regulatory requirements. The facilities had adequate structural shielding rooms to protect workers, patients and the public from the risk of ionising radiation. However, in the operational phase of the facilities, majority of the facilities had the improper management of existing resources and non-implementation of regulatory requirements on time. It was observed that workers in some facilities continued the practice, despite the failure of specific safety functions, or not meeting regulatory requirements. Such practices led to the suspension of patient treatment in three of the facilities by the regulator. The existence of a varying nature of risk perceptions among oncologists, medical physicists, radiological safety officers, radiotherapy technologists in the facilities were observed and these influenced the decision-making process of the facilities on the implementation of regulatory requirements.

Conclusion

The study found that the facilities needed to explore various means, including to narrow the gap that existed in respects of perceived risk (within the facilities), communication to enhance work coordination and mutual trust among workers. The adoption of the institutional policy for conducting an internal audit of working practices, encouragement of workers to participate in continuing education programs would enhance effective utilisation of already existing infrastructure/equipment and work procedures including quality assurance programs.

An Audit for Radiotherapy Planning and Treatment Errors From a Low-Middle-Income Country Centre

AIMS

To report the findings of an audit for radiotherapy errors from a low-middle-income country (LMICs) centre. This would serve as baseline data for radiotherapy error rates, their severity and causes, in such centres where modern error reporting and learning processes still do not exist.

MATERIALS AND METHODS

A planned cross-sectional weekly audit of electronic radiotherapy charts at the radiotherapy planning and delivery step for all patients treated with curative intent was conducted. Detailed analysis was carried out to determine the step of origin of error, time and contributing factors. They were graded as per indigenous institutional (TMC) radiotherapy error grading (TREG) system and the contributing factors identified were prioritised using the product of frequency, severity and ease of detection.

RESULTS

In total, 1005 consecutive radically treated patients' charts were audited, 67 radiotherapy errors affecting 60 patients, including 42 incidents and 25 near-misses were identified. Transcriptional errors (29%) were the most common type. Most errors occurred at the time of treatment planning (59.7%), with "plan information transfer to the radiation oncology information system" being the most frequently affected sub-step of the radiotherapy process (47.8%). More errors were noted at cobalt units (52/67; 77.6%) than at linear accelerators. Trend analysis showed an increased number of radiotherapy incidents on Fridays and near-misses on Mondays. Trend for increased radiotherapy errors noted in the evening over other shifts. On severity grading, most of the errors (54/60; 90%) were clinically insignificant (grade I/II). Inadequacies and non-adherence towards standard operating procedures, poor documentation and lack of continuing education were the three most prominent causes.

CONCLUSION

Preliminary data suggest a vulnerability of LMIC set-up to radiotherapy errors and emphasises the need for the development of longitudinal prospective processes, such as voluntary reporting and a continued education system, to ensure robust and comprehensive safe practises on par with centres in developed countries.

Risk factors for near-miss events and safety incidents in pediatric radiation therapy

BACKGROUND AND PURPOSE

Factors contributing to safety- or quality-related incidents (e.g. variances) in children are unknown. We identified clinical and RT treatment variables associated with risk for variances in a pediatric cohort.

MATERIALS AND METHODS

Using our institution's incident learning system, 81 patients age ≤21 years old who experienced variances were compared to 191 pediatric patients without variances. Clinical and RT treatment variables were evaluated as potential predictors for variances using univariate and multivariate analyses.

RESULTS

Variances were primarily documentation errors (n = 46, 57%) and were most commonly detected during treatment planning (n = 14, 21%). Treatment planning errors constituted the majority (n = 16 out of 29, 55%) of near-misses and safety incidents (NMSI), which excludes workflow incidents. Therapists reported the majority of variances (n = 50, 62%). Physician cross-coverage (OR = 2.1, 95% CI = 1.04-4.38) and 3D conformal RT (OR = 2.3, 95% CI = 1.11-4.69) increased variance risk. Conversely, age >14 years (OR = 0.5, 95% CI = 0.28-0.88) and diagnosis of abdominal tumor (OR = 0.2, 95% CI = 0.04-0.59) decreased variance risk.

CONCLUSIONS

Variances in children occurred in early treatment phases, but were detected at later workflow stages. Quality measures should be implemented during early treatment phases with a focus on younger children and those cared for by cross-covering physicians.

Application of an incident taxonomy for radiation therapy: Analysis of five years of data from three integrated cancer centres

AIM

To develop and apply a clinical incident taxonomy for radiation therapy.

BACKGROUND

Capturing clinical incident information that focuses on near-miss events is critical for achieving higher levels of safety and reliability.

METHODS AND MATERIALS

A clinical incident taxonomy for radiation therapy was established; coding categories were prescription, consent, simulation, voluming, dosimetry, treatment, bolus, shielding, imaging, quality assurance and coordination of care. The taxonomy was applied to all clinical incidents occurring at three integrated cancer centres for the years 2011-2015. Incidents were managed locally, audited and feedback disseminated to all centres.

RESULTS

Across the five years the total incident rate (per 100 courses) was 8.54; the radiotherapy-specific coded rate was 6.71. The rate of true adverse events (unintended treatment and potential patient harm) was 1.06. Adverse events, where no harm was identified, occurred at a rate of 2.76 per 100 courses. Despite workload increases, overall and actual rates both exhibited downward trends over the 5-year period. The taxonomy captured previously unidentified quality assurance failures; centre-specific issues that contributed to variations in incident trends were also identified.

CONCLUSIONS

The application of a taxonomy developed for radiation therapy enhances incident investigation and facilitates strategic interventions. The practice appears to be effective in our institution and contributes to the safety culture. The ratio of near miss to actual incidents could serve as a possible measure of incident reporting culture and could be incorporated into large scale incident reporting systems.

Incident learning in radiation oncology: A review

Incident learning is a key component for maintaining safety and quality in healthcare. Its use is well established and supported by professional society recommendations, regulations and accreditation, and objective evidence. There is an active interest in incident learning systems (ILS) in radiation oncology, with over 40 publications since 2010. This article is intended as a comprehensive topic review of ILS in radiation oncology, including history and summary of existing literature, nomenclature and categorization schemas, operational aspects of ILS at the institutional level including event handling and root cause analysis, and national and international ILS for shared learning. Core principles of patient safety in the context of ILS are discussed, including the systems view of error, culture of safety, and contributing factors such as cognitive bias. Finally, the topics of medical error disclosure and second victim syndrome are discussed. In spite of the rapid progress and understanding of ILS, challenges remain in applying ILS to the radiation oncology context. This comprehensive review may serve as a springboard for further work.

Risk factors for radiotherapy incidents: a single institutional experience

We aimed to analyze risk factors for incidents occurring during the practice of external beam radiotherapy (EBRT) at a single Japanese center. Treatment data for EBRT from June 2014 to March 2017 were collected. Data from incident reports submitted during this period were reviewed. Near-miss cases were not included. Risk factors for incidents, including patient characteristics and treatment-related factors, were explored using uni- and multivariate analyses. Factors contributing to each incident were also retrospectively categorized according to the recommendations of the American Association of Physicists in Medicine (AAPM). A total of 2887 patients were treated during the study period, and 26 incidents occurred (0.90% per patient). Previous history of radiotherapy and large fraction size were identified as risk factors for incidents by univariate analysis. Only previous history of radiotherapy was detected as a risk factor in multivariate analysis. Identified categories of contributing factors were human behavior (50.0%), communication (40.6%), and technical (9.4%). The incident rate of EBRT was 0.90% per patient in our institution. Previous history of radiotherapy and large fraction size were detected as risk factors for incidents. Human behavior and communication errors were identified as contributing factors for most incidents.

A nationwide investigation of radiation therapy event reporting-and-learning systems: Can standards be improved?

INTRODUCTION

Variation exists between event reporting-and-learning systems utilised in radiation therapy. Due to the impact of errors associated with this field of medicine, evidence-based and rigorous systems are imperative. The implementation of such systems facilitates the reactive enhancement of patient safety following an event. The purpose of this study was to evaluate Irish event reporting-and-learning procedures against the current literature using a developed evidence-based process map, and to propose recommendations as to how the national standard could be improved.

METHODS

Radiation Therapy Service Managers of all Irish radiation therapy institutions (n = 12) were invited to participate in an anonymous online questionnaire. Included in the questionnaire was a reporting-and-learning process map developed from evidence-based literature, which was used to assess the institution's practice through the use of vignettes. Frequency analysis of closed-ended questions and thematic analysis of open-ended questions was performed to assess the data.

RESULTS

A 91.7% response rate was achieved. The following areas were found to have the most variation with the evidence-based process map: event classification, external reporting, and dissemination of lessons-learned to a wider audience. Recommendations to standardise practice were made.

CONCLUSION

Opportunities for improvement exist within event reporting-and-learning systems of Irish radiation therapy institutions and recommendations have been made on these. These findings can provide learning for other countries with similar reporting systems.

Identifying Factors and Root Causes Associated With Near-Miss or Safety Incidents in Patients Treated With Radiotherapy: A Case-Control Analysis

Purpose:

To identify factors associated with a near-miss or safety incident (NMSI) in patients undergoing radiotherapy and identify common root causes of NMSIs and their relationship with incident severity.

Methods:

We retrospectively studied NMSIs filed between October 2014 and April 2016. We extracted patient-, treatment-, and disease-specific data from patients with an NMSI (n = 200; incident group) and a similar group of control patients (n = 200) matched in time, without an NMSI. A root cause and incident severity were determined for each NMSI. Univariable and multivariable analyses were performed to determine which specific factors were contributing to NMSIs. Multivariable logistic regression was used to determine root causes of NMSIs and their relationship with incident severity.

Results:

NMSIs were associated with the following factors: head and neck sites (odds ratio [OR], 5.2; P = .01), image-guided intensity-modulated radiotherapy (OR, 3; P = .009), daily imaging (OR, 7; P < .001), and tumors staged as T2 (OR, 3.3; P = .004). Documentation and scheduling errors were the most common root causes (29%). Communication errors were more likely to affect patients ( P < .001), and technical treatment delivery errors were most associated with a higher severity score ( P = .005).

Conclusion:

Several treatment- and disease-specific factors were found to be associated with an NMSI. Overall, our results suggest that complexity (eg, head and neck, image-guided intensity-modulated radiotherapy, and daily imaging) might be a contributing factor for an NMSI. This promotes an idea of developing a more dedicated and robust quality assurance system for complex cases and highlights the importance of a strong reporting system to support a safety culture.

Safety Considerations in Stereotactic Body Radiation Therapy

Although many error pathways are common to both stereotactic body radiation therapy (SBRT) and conventional radiation therapy, SBRT presents a special set of challenges including short treatment courses and high-doses, an enhanced reliance on imaging, technical challenges associated with commissioning, special resource requirements for staff and training, and workflow differences. Emerging data also suggest that errors occur at a higher rate in SBRT treatments. Furthermore, when errors do occur they often have a greater effect on SBRT treatments. Given these challenges, it is important to understand and employ systematic approaches to ensure the quality and safety of SBRT treatment. Here, we outline the pathways by which error can occur in SBRT, illustrated through a series of case studies, and highlight 9 specific well-established tools to either reduce error or minimize its effect to the patient or both.

Departmental Workload and Physician Errors in Radiation Oncology

PURPOSE

The purpose of this work was to evaluate measures of increased departmental workload in relation to the occurrence of physician-related errors and incidents reaching the patient in radiation oncology.

MATERIALS AND METHODS

All data were collected for the year 2013. Errors were defined as forms received by our departmental process improvement team; of these forms, only those relating to physicians were included in the study. Incidents were defined as serious errors reaching the patient requiring appropriate action; these were reported through a separate system. Workload measures included patient volumes and physician schedules and were obtained through departmental records for daily and monthly data. Errors and incidents were analyzed for relation with measures of workload using logistic regression modeling.

RESULTS

Ten incidents occurred in the year. The number of patients treated per day was a significant factor relating to incidents (P < 0.003). However, the fraction of department physicians off-duty and the ratio of patients to physicians were not found to be significant factors relating to incidents. Ninety-one physician-related errors were identified, and the ratio of patients to physicians (rolling average) was a significant factor relating to errors (P < 0.03). The number of patients and the fraction of physicians off-duty were not significant factors relating to errors.A rapid increase in patient treatment visits may be another factor leading to errors and incidents. All incidents and 58% of errors occurred in months where there was an increase in the average number of fields treated per day from the previous month; 6 of the 10 incidents occurred in August, which had the highest average increase at 26%.

CONCLUSIONS

Increases in departmental workload, especially rapid changes, may lead to higher occurrence of errors and incidents in radiation oncology. When the department is busy, physician errors may be perpetuated owing to an overwhelmed departmental checks system, leading to incidents reaching the patient. Insights into workload and workflow will allow for the development of targeted approaches to preventing errors and incidents.