ABSTRACT
OBJECTIVES: A portable respiratory training system with a gyroscope sensor (gyroscope respiratory training system [GRTS]) was developed and the feasibility of respiratory training was evaluated. METHODS: Simulated respiratory waveforms from a respiratory motion phantom and actual respirator waveforms from volunteers were acquired using the GRTS and Respiratory Gating for Scanners system (RGSC). Respiratory training was evaluated by comparing the stability and reproducibility of respiratory waveforms from patients undergoing expiratory breath-hold radiation therapy, with and without the GRTS. The stability and reproducibility of respiratory waveforms were assessed by root mean square error and gold marker placement-based success rate of expiratory breath-hold, respectively. RESULTS: The absolute mean difference for sinusoidal waveforms between the GRTS and RGSC was 2.0%. Among volunteers, the mean percentages of errors within ±15% of the respiratory waveforms acquired by the GRTS and RGSC were 96.1% for free breathing and 88.2% for expiratory breath-hold. The mean root mean square error and success rate of expiratory breath-hold (standard deviation) with and without the GRTS were 0.65 (0.24) and 0.88 (0.89) cm and 91.0% (6.9) and 89.1% (11.6), respectively. CONCLUSIONS: Respiratory waveforms acquired by the GRTS exhibit good agreement with waveforms acquired by the RGSC. Respiratory training with the GRTS reduces inter-patient variability in respiratory waveforms, thereby improving the success of expiratory breath-hold radiation therapy. ADVANCES IN KNOWLEDGE: A respiratory training system with a gyroscope sensor is inexpensive and portable, making it ideal for respiratory training. This is the first report concerning clinical implementation of a respiratory training system.
Subject(s)
Feasibility Studies , Humans , Reproducibility of Results , Male , Adult , Phantoms, Imaging , Female , Breath Holding , Breathing Exercises/instrumentation , Breathing Exercises/methods , Middle Aged , Respiration , Equipment DesignABSTRACT
PURPOSE: The quality assurance (QA) system that simultaneously quantifies the position and duration of an (192)Ir source (dwell position and time) was developed and the performance of this system was evaluated in high-dose-rate brachytherapy. METHODS: This QA system has two functions to verify and quantify dwell position and time by using a web camera. The web camera records 30 images per second in a range from 1,425 mm to 1,505 mm. A user verifies the source position from the web camera at real time. The source position and duration were quantified with the movie using in-house software which was applied with a template-matching technique. RESULTS: This QA system allowed verification of the absolute position in real time and quantification of dwell position and time simultaneously. It was evident from the verification of the system that the mean of step size errors was 0.31±0.1 mm and that of dwell time errors 0.1±0.0 s. Absolute position errors can be determined with an accuracy of 1.0 mm at all dwell points in three step sizes and dwell time errors with an accuracy of 0.1% in more than 10.0 s of the planned time. CONCLUSION: This system is to provide quick verification and quantification of the dwell position and time with high accuracy at various dwell positions without depending on the step size.
Subject(s)
Brachytherapy/instrumentation , Quality Assurance, Health Care/methods , Radiotherapy, Image-Guided/instrumentation , Brachytherapy/methods , Phantoms, Imaging , Radiotherapy Dosage , Radiotherapy, Image-Guided/methodsABSTRACT
Exposure index (EI) is expected as important standard for the optimization of image quality and exposed dose in digital radiography. It is set a region of interest (ROI) in a radiograph, to obtain a histogram of pixel values within an ROI, it is computed as EI of the image representative value of the histogram. In this study, we examined the effects of setting the ROI for EI computing. We set five different ROIs in chest or cervical spine frontal radiograph, and compared the computed EI in each ROIs. From the result, in some cases, we found that EI varied greatly as those compared to the case of ROI set in full image. We should consider about setting the ROI for EI computing when we use EI as standard for optimization of image quality and exposed dose in digital radiography.
