RESUMEN
Recent developments in radiotherapy have focused on the management of patient motion during treatment. Studies have shown that significant gains in treatment quality can be made by 'gating' certain treatments, simultaneously keeping target coverage, and increasing separation to nearby organs at risk (OAR). Motion phantoms can be used to simulate patient breathing motion and provide the means to perform quality control (QC) and quality assurance (QA) of gating functionality as well as to assess the dosimetric impact of motion on individual patient treatments. The aim of this study was to design and build a motion phantom that accurately reproduces the breathing motion of patients to enable end-to-end gating system quality control of various gating systems as well as patient specific quality assurance. A motion phantom based on a stepper motor driver circuit was designed. The phantom can be programmed with both real patient data from an external gating system and with custom signals. The phantom was programmed and evaluated with patient data and with a square wave signal to be tracked with a Sentinel™ (C-Rad, Uppsala, Sweden) motion monitoring system. Results were compared to the original curves with respect to amplitude and phase. The comparison of patient curve data showed a mean error value of -0.09 mm with a standard deviation of 0.24 mm and a mean absolute error of 0.29 mm. The square wave signals could be reproduced with a mean error value of -0.03 mm, a standard deviation of 0.04 mm and a mean absolute error of 0.13 mm. Breathing curve data acquired from an optical scanning system can be reproduced accurately with the help of the in-house built motion phantom. The phantom can also be programmed to follow user designed curve data. This offers the potential for QC of gating systems and various dosimetric quality control applications.
Asunto(s)
Electrónica/instrumentación , Movimiento (Física) , Fenómenos Ópticos , Fantasmas de Imagen , Radioterapia/métodos , Humanos , Respiración , Programas InformáticosRESUMEN
Bioimedical pilot projects e.g., telemedicine, homecare, animal and human trials usually involve several physiological measurements. Technical development of these projects is time consuming and in particular costly. A versatile but affordable biosignal measurement platform can help to reduce time and risk while keeping the focus on the important goal and making an efficient use of resources. In this work, an affordable and open source platform for development of physiological signals is proposed. As a first step an 8-12 leads electrocardiogram (ECG) and respiration monitoring system is developed. Chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 for patient safety. The result shows the potential of this platform as a base for prototyping compact, affordable, and medically safe measurement systems. Further work involves both hardware and software development to develop modules. These modules may require development of front-ends for other biosignals or just collect data wirelessly from different devices e.g., blood pressure, weight, bioimpedance spectrum, blood glucose, e.g., through Bluetooth. All design and development documents, files and source codes will be available for non-commercial use through project website, BiosignalPI.org.