Browsing by Subject "treatment planning"

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    Analysis of Virtual Versus In-Person Prospective Peer Review Workflow in a Multisite Academic Radiation Oncology Department
    (Elsevier, 2021-11) McClelland, Shearwood III; Amy Achiko, Flora; Bartlett, Gregory K.; Watson, Gordon A.; Holmes, Jordan A.; Rhome, Ryan M.; DesRosiers, Colleen M.; Hutchins, Karen M.; Shiue, Kevin; Agrawal, Namita; Radiation Oncology, School of Medicine
    Purpose In radiation oncology, peer review is a process where subjective treatment planning decisions are assessed by those independent of the prescribing physician. Before March 2020, all peer review sessions occurred in person; however due to the COVID-19 pandemic, the peer-review workflow was transitioned from in-person to virtual. We sought to assess any differences between virtual versus in-person prospective peer review. Methods and Materials Patients scheduled to receive nonemergent nonprocedural radiation therapy (RT) were presented daily at prospective peer-review before the start of RT administration. Planning software was used, with critical evaluation of several variables including treatment intent, contour definition, treatment target coverage, and risk to critical structures. A deviation was defined as any suggested plan revision. Results In the study, 274 treatment plans evaluated in-person in 2017 to 2018 were compared with 195 plans evaluated virtually in 2021. There were significant differences in palliative intent (36% vs 22%; P = .002), but not in total time between simulation and the start of treatment (9.2 vs 10.0 days; P = .10). Overall deviations (8.0% in-person vs 2.6% virtual; P = .015) were significantly reduced in virtual peer review. Conclusions Prospective daily peer review of radiation oncology treatment plans can be performed virtually with similar timeliness of patient care compared with in-person peer review. A decrease in deviation rate in the virtual peer review setting will need to be further investigated to determine whether virtual workflow can be considered a standard of care.
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    Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning
    (Medknow Publications, 2016-01) Das, Indra J.; Cheng, Chee-Wai; Cao, Minsong; Johnstone, Peter A. S.; Department of Radiation Oncology, IU School of Medicine
    Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body) with the help of tissue characterization based on computed tomography (CT) number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV), reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED) conversion had been subject of investigation for treatment planning in various clinical situations. This is usually performed with a tissue characterization phantom with various density plugs acquired with different tube voltages (kilovoltage peak), FOV reconstruction and different scanners to generate CT number to ED tables. This article provides an overview of inhomogeneity correction in the context of CT scanning and a new evaluation tool, difference volume dose-volume histogram (DVH), dV-DVH. It has been concluded that scanner and CT parameters are important for tissue characterizations, but changes in ED are minimal and only pronounced for higher density materials. For lungs, changes in CT number are minimal among scanners and CT parameters. Dosimetric differences for lung and prostate cases are usually insignificant (<2%) in three-dimensional conformal radiation therapy and < 5% for intensity-modulated radiation therapy (IMRT) with CT parameters. It could be concluded that CT number variability is dependent on acquisition parameters, but its dosimetric impact is pronounced only in high-density media and possibly in IMRT. In view of such small dosimetric changes in low-density medium, the acquisition of additional CT data for financially difficult clinics and countries may not be warranted.