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Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device.

ABSTRACT: High conformal techniques such as intensity-modulated radiation therapy and volumetric-modulated arc therapy are widely used in overloaded radiotherapy departments. In vivo dosimetric screening is essential in this environment to avoid important dosimetric errors. This work examines the feasibility of introducing in vivo dosimetry (IVD) checks in a radiotherapy routine. The causes of dosimetric disagreements between delivered and planned treatments were identified and corrected during the course of treatment. The efficiency of the corrections performed and the added workload needed for the entire procedure were evaluated. The IVD procedure was based on an electronic portal imaging device. A total of 3682 IVD tests were performed for 147 patients who underwent head and neck, abdomen, pelvis, breast, and thorax radiotherapy treatments. Two types of indices were evaluated and used to determine if the IVD tests were within tolerance levels: the ratio R between the reconstructed and planned isocentre doses and a transit dosimetry based on the ?-analysis of the electronic portal images. The causes of test outside tolerance level were investigated and corrected and IVD test was repeated during subsequent fraction. The time needed for each step of the IVD procedure was registered. Pelvis, abdomen, and head and neck treatments had 10% of tests out of tolerance whereas breast and thorax treatments accounted for up to 25%. The patient setup was the main cause of 90% of the IVD tests out of tolerance and the remaining 10% was due to patient morphological changes. An average time of 42 min per day was sufficient to monitor a daily workload of 60 patients in treatment. This work shows that IVD performed with an electronic portal imaging device is feasible in an overloaded department and enables the timely realignment of the treatment quality indices in order to achieve a patient's final treatment compliant with the one prescribed.

SUBMITTER: Li J

PROVIDER: S-EPMC5809064 | biostudies-other | 2018

REPOSITORIES: biostudies-other

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Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device.

Li Jie J Piermattei Angelo A Wang Pei P Kang Shengwei S Xiao Mingyong M Tang Bin B Liao Xiongfei X Xin Xin X Grusio Mattia M Orlandini Lucia Clara LC

PloS one 20180212 2

High conformal techniques such as intensity-modulated radiation therapy and volumetric-modulated arc therapy are widely used in overloaded radiotherapy departments. In vivo dosimetric screening is essential in this environment to avoid important dosimetric errors. This work examines the feasibility of introducing in vivo dosimetry (IVD) checks in a radiotherapy routine. The causes of dosimetric disagreements between delivered and planned treatments were identified and corrected during the course ...[more]

PMID: 29432473

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Project description:BackgroundElectronic medical record (EMR) chronic disease measurement can help direct primary care prevention and treatment strategies and plan health services resource management. Incomplete data and poor consistency of coded disease values within EMR problem lists are widespread issues that limit primary and secondary uses of these data. These issues were shared by the McMaster University Sentinel and Information Collaboration (MUSIC), a primary care practice-based research network (PBRN) located in Hamilton, Ontario, Canada.ObjectiveWe sought to develop and evaluate the effectiveness of new EMR interface tools aimed at improving the quantity and the consistency of disease codes recorded within the disease registry across the MUSIC PBRN.MethodsWe used a single-arm prospective trial design with preintervention and postintervention data analysis to assess the effect of the intervention on disease recording volume and quality. The MUSIC network holds data on over 75,080 patients, 37,212 currently rostered. There were 4 MUSIC network clinician champions involved in gap analysis of the disease coding process and in the iterative design of new interface tools. We leveraged terminology standards and factored EMR workflow and usability into a new interface solution that aimed to optimize code selection volume and quality while minimizing physician time burden. The intervention was integrated as part of usual clinical workflow during routine billing activities.ResultsAfter implementation of the new interface (June 25, 2017), we assessed the disease registry codes at 3 and 6 months (intervention period) to compare their volume and quality to preintervention levels (baseline period). A total of 17,496 International Classification of Diseases, 9th Revision (ICD9) code values were recorded in the disease registry during the 11.5-year (2006 to mid-2017) baseline period. A large gain in disease recording occurred in the intervention period (8516/17,496, 48.67% over baseline), resulting in a total of 26,774 codes. The coding rate increased by a factor of 11.2, averaging 1419 codes per month over the baseline average rate of 127 codes per month. The proportion of preferred ICD9 codes increased by 17.03% in the intervention period (11,007/17,496, 62.91% vs 7417/9278, 79.94%; χ21=819.4; P<.001). A total of 45.03% (4178/9278) of disease codes were entered by way of the new screen prompt tools, with significant increases between quarters (Jul-Sep: 2507/6140, 40.83% vs Oct-Dec: 1671/3148, 53.08%; χ21=126.2; P<.001).ConclusionsThe introduction of clinician co-designed, workflow-embedded disease coding tools is a very effective solution to the issues of poor disease coding and quality in EMRs. The substantial effectiveness in a routine care environment demonstrates usability, and the intervention detail described here should be generalizable to any setting. Significant improvements in problem list coding within primary care EMRs can be realized with minimal disruption to routine clinical workflow.

Project description:The continuous scanning mode of electronic portal imaging devices (EPID) that offers time-resolved information has been newly explored for verifying dynamic radiation deliveries. This study seeks to determine operating conditions (dose rate stability and time resolution) under which that mode can be used accurately for the time-resolved dosimetry of intensity-modulated radiation therapy (IMRT) beams.The authors have designed the following test beams with variable beam holdoffs and dose rate regulations: a 10 × 10 cm open beam to serve as a reference beam; a sliding window (SW) beam utilizing the motion of a pair of multileaf collimator (MLC) leaves outside the 10 × 10 cm jaw; a step and shoot (SS) beam to move the pair in step; a volumetric modulated arc therapy (VMAT) beam. The beams were designed in such a way that they all produce the same open beam output of 10 × 10 cm. Time-resolved ion chamber measurements at isocenter and time-resolved and integrating EPID measurements were performed for all beams. The time-resolved EPID measurements were evaluated through comparison with the ion chamber and integrating EPID measurements, as the latter are accepted procedures. For two-dimensional, time-resolved evaluation, a VMAT beam with an infield MLC travel was designed. Time-resolved EPID measurements and Monte Carlo calculations of such EPID dose images for this beam were performed and intercompared.For IMRT beams (SW and SS), the authors found disagreement greater than 2%, caused by frame missing of the time-resolved mode. However, frame missing disappeared, yielding agreement better than 2%, when the dose rate of irradiation (and thus the frame acquisition rates) reached a stable and planned rate as the dose of irradiation was raised past certain thresholds (a minimum 12 s of irradiation per shoot used for SS IMRT). For VMAT, the authors found that dose rate does not affect the frame acquisition rate, thereby causing no frame missing. However, serious inplanar nonuniformities were found. This could be overcome by sacrificing temporal resolution (10 frames or 0.95 s/image): the continuous images agreed with ion chamber responses at the center of EPID and the calculation two-dimensionally in a time-resolved manner.The authors have determined conditions under which the continuous mode can be used for time-resolved dosimetry of fixed-gantry IMRT and VMAT and demonstrated it for VMAT.

Project description:PurposeTo evaluate the effect of introduction of iterative reconstruction as a mandated software upgrade on radiation dosimetry in routine clinical practice over a range of computed tomography examinations.MethodsRandom samples of scanning data were extracted from a centralised Picture Archiving Communication System pertaining to 10 commonly performed computed tomography examination types undertaken at two hospitals in Western Australia, before and after the introduction of iterative reconstruction. Changes in the mean dose length product and effective dose were evaluated along with estimations of associated changes to annual cancer incidence.ResultsWe observed statistically significant reductions in the effective radiation dose for head computed tomography (22-27%) consistent with those reported in the literature. In contrast the reductions observed for non-contrast chest (37-47%); chest pulmonary embolism study (28%), chest/abdominal/pelvic study (16%) and thoracic spine (39%) computed tomography. Statistically significant reductions in radiation dose were not identified in angiographic computed tomography. Dose reductions translated to substantial lowering of the lifetime attributable risk, especially for younger females, and estimated numbers of incident cancers.ConclusionReduction of CT dose is a priority Iterative reconstruction algorithms have the potential to significantly assist with dose reduction across a range of protocols. However, this reduction in dose is achieved via reductions in image noise. Fully realising the potential dose reduction of iterative reconstruction requires the adjustment of image factors and forgoing the noise reduction potential of the iterative algorithm. Our study has demonstrated a reduction in radiation dose for some scanning protocols, but not to the extent experimental studies had previously shown or in all protocols expected, raising questions about the extent to which iterative reconstruction achieves dose reduction in real world clinical practice.

Dataset Information

Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device.

Publications

Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device.

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