have performed constancy checks on photon beams and electron beams delivered by Varian Clinac 21EX Linac using RBA-3 dose constancy check software.
#Reverse ishikawa diagram software#
have performed using RBA-5 dose constancy check software on their Varian Linac 2100C machine. 14 On the investigation of machine QA results on Linear Accelerators (Linac) using SPC techniques, 15, 16, 17 a smaller body of research exists, like the one Todd Pawlicki et al. 13 Output and energy variations in helical tomotherapy treatment systems have been investigated using SPC methodology. Specifically in the domain of radiotherapy, SPC has of late been commonly used for evaluating patient QA parameters in prostate, 5, 6, 7, 8 head-and-neck 9, 10, 11 and breast cancer patients, 12 and also for comparing results obtained from different dose delivery techniques in radiotherapy including Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT). Control charts have been used in industrial manufacturing for many decades and have also recently been used in healthcare. 3Īccording to Pawlicki and Whitaker, 4 the goal of modern QA in medical treatment is not only to ensure that a process is on target, but also to verify that it also operates with minimal variation. According to Diana Binny et al., the fundamental concept of SPC is to compare current statistics in a process with its previous corresponding statistics for a given period. It is a statistical tool used to determine process stability and to improve process performance by reducing variation. For a process occurring periodically over time, a control chart is a means used to detect departures from a state of ideal statistical control in spite of being within the clinical action limits.
Out of the seven basic tools of quality, control charts are of premium importance while performing SPC in the field of radiotherapy. Unlike the classical approach of using the mean and standard deviation of the sampled data to characterise a process, Statistical Process Control (SPC) permits a more robust monitoring of the stability of process variability in time. This data could allow the physicist to observe in real-time the trends in variation, identify possible systematic errors within the machine, comment on the accuracy of dose delivery and, subsequently, take corrective measures as may be required. 2 While this approach may be sufficient to prevent incorrect delivery of radiation, by adopting the goalpost approach a medical physicist misses the possibility of analysing the actual data obtained during QA. have measured output and energy fluctuations of daily QA checks on a helical tomotherapy system. have developed a novel approach towards developing QA standards through statistical analysis and its incorporation into the treatment preparation chain. A considerable amount of research has been carried out to improve QA procedures based on this approach. Following this principle, a parameter falling within an allowable and predetermined range is deemed acceptable, without further investigation into the exact value of the parameter. The conventional approach to QA used traditionally in radiotherapy advocates the use of the “goalpost principle” used commonly in statistics. Relevant parameters of the photon beam are measured in the process, and the machine is deemed fit for treatment only if the parameters fall within certain pre-specified ranges (unilateral or bilateral as the case may demand). Deviation from the baselines can cause incorrect treatment of patients on that system and, therefore, such deviations must necessarily be detected by the process of QA.
For performing machine QA, the baseline values are fed into the treatment planning system (TPS) for the purpose of characterizing the treatment machine. Quality Assurance (QA) is done to ensure that the machine characteristics do not deviate significantly from the baselines acquired at the time of commissioning. In the process of radiotherapy, it is essential to evaluate the performance of the equipment delivering radiation to the patient.
0 kommentar(er)
