Background: Proton therapy (PT) has unique biologic properties with excellent clinical outcomes for the management of localized prostate cancer. Here, we aim to characterize the toxicity of PT for patients with localized prostate cancer and propose mitigation strategies using a large institutional database.
Methods: We reviewed medical records of 2772 patients with localized prostate cancer treated with definitive PT between May 2006 through January 2020.
Background And Purpose: Proton therapy (PT) has emerged as a standard-of-care treatment option for localized prostate cancer at our comprehensive cancer center. However, there are few large-scale analyses examining the long-term clinical outcomes. Therefore, this article aims to evaluate the long-term effectiveness and toxicity of PT in patients with localized prostate cancer.
View Article and Find Full Text PDFPurpose: The main purpose of this work was to generate and validate the dosimetric accuracy of proton beams of dimensions that are appropriate for in vivo small animal and in vitro ultrahigh dose rate (FLASH) radiotherapy experiments using a synchrotron-based treatment delivery system. This study was performed to enable future investigations of the relevance of a spread-out Bragg peak (SOBP) under FLASH conditions.
Methods: The spill characteristics of the small field fixed horizontal beam line were modified to deliver accelerated protons in times as short as 2 ms and to control the dose delivered.
Purpose: We compared mandibular doses and osteoradionecrosis in patients with oropharyngeal cancer after intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT).
Methods And Materials: We identified 584 patients who received definitive radiotherapy for oropharyngeal cancer from January 2011 through June 2014 at MD Anderson Cancer Center (534 IMRT and 50 IMPT). The dosimetric variables and osteoradionecrosis were compared with Chi-square test or Fisher's exact test.
Purpose: To report prostate cancer outcomes, toxicity, and quality of life (QOL) in men treated with proton beam therapy (PBT).
Patients And Methods: Patients were enrolled in a prospective trial. All participants received 75.
Respiratory motion is traditionally assessed using tumor motion magnitude. In proton therapy, respiratory motion causes density variations along the beam path that result in uncertainties of proton range. This work has investigated the use of water-equivalent thickness (WET) to quantitatively assess the effects of respiratory motion on calculated dose in passively scattered proton therapy (PSPT).
View Article and Find Full Text PDFProton beam therapy (PBT) offers the potential of dose escalation to target tissue while decreasing toxicity through unique physical dose deposition characteristics. PBT has been used to treat prostate cancer for several decades; however, recent enhancements in availability and treatment delivery have peaked interest in this technology among radiation oncologists, industry experts, and prostate cancer patients. As a result, the importance of understanding the collective experience and technical aspects of PBT delivery has become increasingly important in radiation medicine.
View Article and Find Full Text PDFPurpose: To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT).
Methods And Materials: Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT).
Purpose: Robust optimization leads to intensity-modulated proton therapy (IMPT) plans that are less sensitive to uncertainties and superior in terms of organs-at-risk (OARs) sparing, target dose coverage, and homogeneity compared to planning target volume (PTV)-based optimized plans. Robust optimization incorporates setup and range uncertainties, which implicitly adds margins to both targets and OARs and is also able to compensate for perturbations in dose distributions within targets and OARs caused by uncertainties. In contrast, the traditional PTV-based optimization considers only setup uncertainties and adds a margin only to targets but no margins to the OARs.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
August 2012
Purpose: To report acute toxicities and preliminary outcomes for pediatric patients with ependymomas of the spine treated with proton beam therapy at the MD Anderson Cancer Center.
Methods And Materials: Eight pediatric patients received proton beam irradiation between October 2006 and September 2010 for spinal ependymomas. Toxicity data were collected weekly during radiation therapy and all follow-up visits.
Purpose: The purposes of this study were to validate a discrete spot scanning proton beam nozzle using the Monte Carlo (MC) code MCNPX and use the MC validated model to investigate the effects of a low-dose envelope, which surrounds the beam's central axis, on measurements of integral depth dose (IDD) profiles.
Methods: An accurate model of the discrete spot scanning beam nozzle from The University of Texas M. D.
Purpose: Conventional proton therapy with passively scattered beams is used to treat a number of tumor sites, including prostate cancer. Spot scanning proton therapy is a treatment delivery means that improves conformal coverage of the clinical target volume (CTV). Placement of individual spots within a target is dependent on traversed tissue density.
View Article and Find Full Text PDFA range modulator wheel (RMW) is an essential component in passively scattered proton therapy. We have observed that a proton beam spot may shine on multiple steps of the RMW. Proton dose calculation algorithms normally do not consider the partial shining effect, and thus overestimate the dose at the proximal shoulder of spread-out Bragg peak (SOBP) compared with the measurement.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
February 2007
Purpose: To determine the dosimetric impact of interfraction anatomic movements in prostate cancer patients receiving proton therapy.
Methods And Materials: For each of the 10 patients studied, 8 computed tomography (CT) scans were selected from sets of daily setup CT images that were acquired from a cohort of prostate cancer patients. The images were acquired in the treatment room using the CT-on-rails system.
Historically, there have been a variety of dosimetry protocols used for kilovoltage x-ray therapy beams with a set of conversion factors and correction factors taken from different references. Corresponding to the continued installation and use of kilovoltage machines, the American Association of Physicists in Medicine (AAPM) presented a unified protocol developed by Task Group 61 (TG61). TG61 determines the absorbed dose to water with an ionization chamber calibrated in air in terms of air kerma (Nk).
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