Abstract
Treatment of the wrong body part due to incorrect setup is among the leading types of errors in radiotherapy. The purpose of this paper is to report an efficient automatic patient safety system (PSS) to prevent gross setup errors. The system consists of a pair of charge‐coupled device (CCD) cameras mounted in treatment room, a single infrared reflective marker (IRRM) affixed on patient or immobilization device, and a set of in‐house developed software. Patients are CT scanned with a CT BB placed over their surface close to intended treatment site. Coordinates of the CT BB relative to treatment isocenter are used as reference for tracking. The CT BB is replaced with an IRRM before treatment starts. PSS evaluates setup accuracy by comparing real‐time IRRM position with reference position. To automate system workflow, PSS synchronizes with the record‐and‐verify (R&V) system in real time and automatically loads in reference data for patient under treatment. Special IRRMs, which can permanently stick to patient face mask or body mold throughout the course of treatment, were designed to minimize therapist's workload. Accuracy of the system was examined on an anthropomorphic phantom with a designed end‐to‐end test. Its performance was also evaluated on head and neck as well as abdominalpelvic patients using cone‐beam CT (CBCT) as standard. The PSS system achieved a seamless clinic workflow by synchronizing with the R&V system. By permanently mounting specially designed IRRMs on patient immobilization devices, therapist intervention is eliminated or minimized. Overall results showed that the PSS system has sufficient accuracy to catch gross setup errors greater than 1 cm in real time. An efficient automatic PSS with sufficient accuracy has been developed to prevent gross setup errors in radiotherapy. The system can be applied to all treatment sites for independent positioning verification. It can be an ideal complement to complex image‐guidance systems due to its advantages of continuous tracking ability, no radiation dose, and fully automated clinic workflow.PACS number: 87.55.Qr
Highlights
323 Yan et al.: Prevention of gross setup errors multistep, multiperson process and errors can occur at any point
We report an efficient, automatic patient safety system (PSS) which addresses issues contributing to gross setup errors and safeguards patient treatment
We have developed a simple and efficient daily quality assurance (QA) procedure which can be integrated with other daily QA activities, the majority of which are performed with a daily QA device (Daily QA3, Sun Nuclear Corp., Melbourne, FL).(15) At the time of initial system calibration, an infrared reflective marker (IRRM) is permanently mounted on the end side of the daily QA device (see Fig. 1(d)), facing the cameras
Summary
323 Yan et al.: Prevention of gross setup errors multistep, multiperson process and errors can occur at any point. One of the prominent causes for radiotherapy incidents is geometric miss due to incorrect patient setup, which leads to the treatment of incorrect body parts with more than 1 cm spatial discrepancy.[3,4] Geometric miss can result in significant underdose to the target which can cause tumor recurrence, and overdose to healthy tissue with severe normal tissue complications. In hypofractionated radiotherapy such as stereotactic body radiotherapy (SBRT), it may result in even more severe morbidity than traditional radiotherapy.
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