Quality management in radiotherapy: A 9-year review of incident reporting within a multifacility organisation

Background: A radiotherapy incident reporting system should (1) record and classify incidents, (2) assess the impact of incidents on patients in terms of dose errors and (3) identify areas of improvement in the incident reporting system. Such a system at the Independent Clinical Oncology Network (ICON) Oncology is investigated.Aim: An ‘incident’ is defined by ICON as ‘any occurrence that may prevent the patient from receiving the prescribed dose in the prescribed time period or may cause unplanned harm to the patient or may infringe upon the patient’s rights’.Setting: Incidents reported between December 2011 and December 2020.Methods: Incidents were analysed looking at various factors such as institutional timelines compared with major projects, incident error and areas, reporting frequencies amongst tumour-sites and professional groups.Results: Over the course of 9-years, 78 521 patients were treated at ICON’s centres and a total of 924 reports were filed involving 1355 patients. This shows an incident rate of 1.7% of all patients in radiotherapy. The difference in incident number versus patients is because one incident may involve many patients. Reporting amongst professional groups has more distinctive differences, with 86.0%, 11.6% and 2.4% reported cases per annum for radiotherapists, physicist and oncologist, respectively. For the errors in dose-delivery, 43.0% of the incidents were discovered with no dosimetric or clinical consequence, 53.6% with dosimetric consequence but no clinical consequence and 3.4% with dosimetric and clinical consequence.Conclusion: Incident reporting is not a new quality assurance (QA) indicator for radiotherapy treatment. However, it requires continuous effort and innovation to uphold and maintain a high standard of patient and staff safety within an organisation. Errors are present during every stage of the radiotherapy process, whether it be human, technical, organisational or patient related. From the statistics of all the patients treated at ICON, 0.04% have been reported to have had an associated incident that involved some form of clinical consequence. Yet, if undetected, the incident could lead to increase in dose errors to patients.

Influence of respiratory movement during regional nodal irradiation after mastectomy for breast cancer: an experimental study

Background This study aimed to evaluate the dosimetric consequences of respiratory movement in postmastectomy radiation therapy (PMRT) including internal mammary nodes (IMNs) between volumetric modulated arc therapy (VMAT) and three-dimensional conformal radiation therapy (3D-CRT).Methods An anthropomorphic phantom was used to mimic the chest anatomy of a patient who had undergone mastectomy. Two types of absorbed dose measurements were adopted; a radiochromic film was inserted into a gap between phantom slices at the level of the second IMN and three glass rod dosimeters were placed at the first IMN (IM), chest wall (CW), and left anterior descending (LAD) artery. Respiratory movements with amplitudes of 5 mm (R05) and 10 mm (R10) were simulated using a dynamic platform combined with a motorized jack. To evaluate dose errors caused by respiratory movement, the measured data in the presence and absence of respiratory movement were compared.Results At IM, dose errors were − 2.8% (R05) and − 6.2% (R10) for 3D-CRT and − 4.9% (R05) and − 8.5% (R10) for VMAT. The dose errors in CW were − 0.5% (R05) and − 6.0% (R10) for 3D-CRT and − 1.9% (R05) and − 5.3% (R10) for VMAT. The LAD doses showed very small absolute values. According to film measurements, dose errors of IMN were similar between 3D-CRT and VMAT, but the dose error of the lung was higher in 3D-CRT. The gamma pass rates of VMAT (97% at R05; 88% at R10) were higher than those of 3D-CRT (74% at R05; 59% at R10).Conclusions If the patient maintained shallow to normal breathing, PMRT including IMNs could be implemented with acceptable accuracy. In particular, it was possible to maintain the advantages of VMAT, which enabled high-target coverage and normal organ protection.