A real-time respiration position based passive breath gating equipment for gated radiotherapy: A preclinical evaluation (original) (raw)
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Recent Technological Advancements in Respiratory Gating Devices
Indonesian Journal of Cancer, 2023
Background: The occurrence of motion in the thoracoabdominal region during radiotherapy treatment is an inherent challenge affecting the accuracy of the radiation beam. To address this challenge, a margin is often incorporated to compensate for the motion, but it has been reported to have several limitations. Consequently, respiratory gating has emerged as an integrated feature within radiotherapy-related machines. This innovative approach is designed to overcome motion-related challenges, leading to a reduction in the required margin and an improvement in the accuracy of the radiation beam. Methods: This study reviews the literature published in English between 2012 to 2021 regarding breathing monitoring devices used in the clinical or research stage. Furthermore, articles published before 2000 were traced to strengthen the theories. Results: Several monitoring devices had been reported to have respiratory gating purposes, but some were not equipped for this function. Furthermore, these devices were often developed using non-contact equipment, such as lasers and cameras, to provide accurate and precise measurements. One of their key advantages is the lack of physical attachment to the patients, thereby preserving comfort. The development of respiratory gating devices had significant potential to enhance the quality of radiotherapy treatment. This was manifested through more effective tumor and organ treatment and reduced toxicity. These benefits had the potential to extend the life expectancy of patients with respiratory-related cancer. Conclusions: Based on the results, respiratory gating was an advantageous technique in radiotherapy treatment. The development of respiratory gating devices enhanced patient comfort and the effectiveness of treatment.
Journal of Medical Signals & Sensors
Background: Deep inspiration breath-hold (DIBH) is known as a radiotherapy method for the treatment of patients with left-sided breast cancer. In this method, patient is under exposure only while he/she is at the end of a deep inspiration cycle and holds his/her breath. In this situation, the volume of the lung tissue is enhanced and the heart tissue is pushed away from the treating breast. Therefore, heart dose of these patients, using DIBH, experiences a considerable decline compared to free breathing treatment. There are a few commercialized systems for implementation of DIBH in invasive or noninvasive manners. Methods: We present a novel constructed noninvasive DIBH device relied on a manufacturing near-field laser distance meter. This in-house constructed system is composed of a CD22-100AM122 laser sensor combined with a data acquisition system for monitoring the breathing curve. Qt Creator (a cross-platform JavaScript, QML, and C++-integrated development environment that is part of the SDK for development of the Qt Graphical User Interface application framework) and Keil MDK-ARM (a programming software where users can write in C and C++ and assemble for ARM-based microcontrollers) are used for composing computer and microcontroller programs, respectively. Results: This system could be mounted in treatment or computed tomography (CT) room at suitable cost; it is also easy to use and needs a little training for personnel and patients. The system can assess the location of chest wall or abdomen in real time with high precision and frequency. The performance of CD22-100AM122 demonstrates promise for respiratory monitoring for its fast sampling rate as well as high precision. It can also deliver reasonable spatial and temporal accuracy. The patient observes his/her breathing waveform through a 7" 1024 × 600 liquid crystal display and gets some instructions during treatment and CT sessions by an exploited algorithm called "interaction scenario" in this study. The system is also noninvasive and well sustainable for patients. Conclusions: The constructed system has true real-time operation and is rapid enough for delivering clear contiguous monitoring. In addition, in this system, we have provided an interaction scenario option between patient and CT or Linac operator. In addition, the constructed system has the capability of sending triggers for turning on and off CT or Linac facilities. In this concern, the system has the superiority of combining a plenty of characteristics.
Evaluation of integrated respiratory gating systems on a Novalis Tx system
Journal of applied clinical medical physics / American College of Medical Physics, 2011
The purpose of this study was to investigate the accuracy of motion tracking and radiation delivery control of integrated gating systems on a Novalis Tx system. The study was performed on a Novalis Tx system, which is equipped with Varian Real-time Position Management (RPM) system, and BrainLAB ExacTrac gating systems. In this study, the two systems were assessed on accuracy of both motion tracking and radiation delivery control. To evaluate motion tracking, two artificial motion profiles and five patients' respiratory profiles were used. The motion trajectories acquired by the two gating systems were compared against the references. To assess radiation delivery control, time delays were measured using a single-exposure method. More specifically, radiation is delivered with a 4 mm diameter cone within the phase range of 10%-45% for the BrainLAB ExacTrac system, and within the phase range of 0%-25% for the Varian RPM system during expiration, each for three times. Radiochromic fi...
Progress in Medical Physics
This study aimed to develop a breath control training system for breath-hold technique and respiratory-gated radiation therapy wherein the patients can learn breath-hold techniques in their convenient environment. Methods: The breath control training system comprises a sensor device and software. The sensor device uses a loadcell sensor and an adjustable strap around the chest to acquire respiratory signals. The device connects via Bluetooth to a computer where the software is installed. The software visualizes the respiratory signal in near real-time with a graph. The developed system can signal patients through visual (software), auditory (buzzer), and tactile (vibrator) stimulation when breath-holding starts. A motion phantom was used to test the basic functions of the developed breath control training system. The relative standard deviation of the maxima of the emulated free breathing data was calculated. Moreover, a relative standard deviation of a breath-holding region was calculated for the simulated breath-holding data. Results: The average force of the maxima was 487.71 N, and the relative standard deviation was 4.8%, while the average force of the breath hold region was 398.5 N, and the relative standard deviation was 1.8%. The data acquired through the sensor was consistent with the motion created by the motion phantom. Conclusions: We have developed a breath control training system comprising a sensor device and software that allow patients to learn breath-hold techniques in their convenient environment.
International Journal of Radiation Oncology Biology Physics, 2004
Purpose: To investigate the clinical use of a commercially available gating system for minimizing respiratoryinduced anatomic motion over a range of treatment sites. Methods and Materials: The gating system consists of a reflective marker placed on the patient's anterior surface. The motion of the marker is tracked using a camera interfaced to a computer. Gated intervals were defined that limited the motion of the diaphragm to less than 1 cm during free breathing. Patients underwent a computed tomography virtual simulation using a breath-hold technique. At the time of treatment, verification of patient position and gating interval were performed using electronic portal imaging. Results: Between September 2000 and January 2002, 136 patients were simulated with respiratory gating. Of these, 108 patients were treated to 110 sites for a total of 2301 treatment sessions. Ninety-seven percent of patients completed their entire course of therapy with gated treatment delivery. Conclusions: Respiratory gating is a practical and achievable solution for minimizing respiratory-induced target motion during both simulation and treatment. With proper patient selection and training, it can be successfully implemented in a clinical radiation therapy department.
Real time transit dosimetry for the breath-hold radiotherapy technique: An initial experience
Acta Oncologica, 2008
Introduction. The breath-hold is one of the techniques to obtain the dose escalation for lung tumors. However, the change of the patient's breath pattern can influence the stability of the inhaled air volume, IAV, used in this work as a surrogate parameter to assure the tumor position reproducibility during dose delivery.Materials. and methodIn this paper, an Elekta active breathing coordinator has been used for lung tumor irradiation. This device is not an absolute spirometer and the feasibility study here presented developed (i) the possibility to select a specific range o of IAV values comfortable for the patient and (ii) the ability of a transit signal rateṠ t ; obtained by a small ion-chamber positioned on the portal image device, to supply in real time the in vivo isocenter dose reproducibility. Indeed, while the selection of the IAV range depends on the patient's ability to follow instructions for breath-hold, theṠ t monitoring can supply to the radiation therapist a surrogate of the tumor irradiation reproducibility.Results. The detection of theṠ t in real time during breath-hold was used to determine the interfraction isocenter dose variations due to the reproducibility of the patient's breathing pattern. The agreement between the reconstructed and planned isocenter dose in breath-hold at the interfraction level was well within 1.5%, while in free breathing a disagreement up to 8% was observed. The standard deviation of theṠ t in breath-hold observed at the intrafraction level is a bit higher than the one obtained without the patient and this can be justified by the presence of a small residual tumor motion as heartbeat.Conclusion. The technique is simple and can be implemented for routine use in a busy clinic.
Radiotherapy and Oncology, 2009
Introduction One method to overcome the problem of lung tumour movement in patients treated with radiotherapy is to restrict tumour motion with an Active Breathing Control (ABC) device. This study evaluated the feasibility of using ABC in patients receiving radical radiotherapy for non small cell lung cancer. Method 18 patients, median (range) age of 66 (44-82)years, were consented for the study. A training session was conducted to establish the patient's breath hold level and breath hold time. Three planning scans were acquired using the ABC device. Reproducibility of breath hold was assessed by comparing lung volumes measured from the planning scans and the volume recorded by ABC. Patients were treated with a 3-field coplanar beam arrangement and treatment time (patient on and off the bed) and number of breath holds recorded. The tolerability of the device was assessed by weekly questionnaire. Quality assurance was performed on the two ABC devices used. Results 17/18 patients completed 32 fractions of radiotherapy using ABC. All patients tolerated a maximum breath hold time >15secs. The mean (SD) patient training time was 13.8 (4.8) min and no patient found the ABC very uncomfortable. 6-13 breath holds of 10-14 secs were required per session. The mean treatment time was 15.8 mins (5.8 mins). The breath hold volumes were reproducible during treatment and also between the two ABC devices. Conclusion The use of ABC in patients receiving radical radiotherapy for NSCLC is feasible. It was not possible to predict a patient's ability to breath hold. A minimum tolerated breath hold time of 15 seconds is recommended prior to commencing treatment.
Dosimetric benefits of respiratory gating: a preliminary study
Journal of Applied …, 2004
In this study, we compared the amount of lung tissue irradiated when respiratory gating was imposed during expiration with the amount of lung tissue irradiated when gating was imposed during inspiration. Our hypothesis was that the amount of lung tissue spared increased as ...
International Journal of Radiation Oncology*Biology*Physics, 2002
Purpose: To evaluate the effectiveness of a commercial system 1 in reducing respiration-induced treatment uncertainty by gating the radiation delivery. Methods and Materials: The gating system considered here measures respiration from the position of a reflective marker on the patient's chest. Respiration-triggered planning CT scans were obtained for 8 patients (4 lung, 4 liver) at the intended phase of respiration (6 at end expiration and 2 at end inspiration). In addition, fluoroscopic movies were recorded simultaneously with the respiratory waveform. During the treatment sessions, gated localization films were used to measure the position of the diaphragm relative to the vertebral bodies, which was compared to the reference digitally reconstructed radiograph derived from the respiration-triggered planning CT. Variability was quantified by the standard deviation about the mean position. We also assessed the interfraction variability of soft tissue structures during gated treatment in 2 patients using an amorphous silicon electronic portal imaging device. Results: The gated localization films revealed an interfraction patient-averaged diaphragm variability of 2.8 ؎ 1.0 mm (error bars indicate standard deviation in the patient population). The fluoroscopic data yielded a patient-averaged intrafraction diaphragm variability of 2.6 ؎ 1.7 mm. With no gating, this intrafraction excursion became 6.9 ؎ 2.1 mm. In gated localization films, the patient-averaged mean displacement of the diaphragm from the planning position was 0.0 ؎ 3.9 mm. However, in 4 of the 8 patients, the mean (over localization films) displacement was >4 mm, indicating a systematic displacement in treatment position from the planned one. The position of soft tissue features observed in portal images during gated treatments over several fractions showed a mean variability between 2.6 and 5.7 mm. The intrafraction variability, however, was between 0.6 and 1.4 mm, indicating that most of the variability was due to patient setup errors rather than to respiratory motion. Conclusions: The gating system evaluated here reduces the intra-and interfraction variability of anatomy due to respiratory motion. However, systematic displacements were observed in some cases between the location of an anatomic feature at simulation and its location during treatment. Frequent monitoring is advisable with film or portal imaging.