Publications by authors named "Arthur Olch"

The time-consuming process of manual contouring of healthy tissue and organs in radiation therapy has prompted the development of computational systems to aid and automate this process, such as artificial intelligence (AI) segmentation and interpolation algorithms. These algorithms are useful in saving time, however, they are not always accurate. Fixing such inaccuracies by editing contours is a manual, time-consuming process as no 'undo' feature currently exists in the most commonly used treatment planning system (TPS).

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Article Synopsis
  • Children with posterior fossa tumors treated with cranial irradiation (CRT) often experience significant cognitive deficits, affecting areas like spatial learning and memory compared to healthy peers.
  • Neuroimaging revealed that those receiving CRT had smaller thalamic volumes and negative correlations between radiation doses to the hippocampus and cognitive performance.
  • The study indicates that cranial irradiation can adversely impact critical brain structures, resulting in long-term cognitive challenges for affected children.
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Purpose: Standardized and accurately reported doses are essential in conventional total body irradiation (TBI), especially lung doses. This study evaluates the accuracy of the Acuros algorithm in predicting doses for extended-distance TBI.

Methods: Measurements and calculations were done with both 6 and 18 MV.

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The major aim of Pediatric Normal Tissue Effects in the Clinic (PENTEC) was to synthesize quantitative published dose/-volume/toxicity data in pediatric radiation therapy. Such systematic reviews are often challenging because of the lack of standardization and difficulty of reporting outcomes, clinical factors, and treatment details in journal articles. This has clinical consequences: optimization of treatment plans must balance between the risks of toxicity and local failure; counseling patients and their parents requires knowledge of the excess risks encountered after a specific treatment.

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Article Synopsis
  • Radiation oncology balances the benefits and risks of high doses of ionizing radiation on tumors and normal tissues, which is crucial for childhood cancer survivors (CCS) who may face significant long-term consequences.
  • The Pediatric Normal-Tissue Effects in the Clinic (PENTEC) network aims to analyze and compile dose-volume-response relationships related to adverse events in CCS to guide safer radiation therapy decisions.
  • Challenges in studying CCS include their rarity, diverse cancer types, increased health risks beyond radiation exposure, variable study methodologies, and the long delay before adverse effects manifest, complicating risk assessments and data synthesis.
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Purpose: Radiation myelitis (RM) is a rare complication of radiation therapy (RT). The Pediatric Normal Tissue Effects in the Clinic spinal cord task force aimed to identify RT dose effects and assess risk factors for RM in children. Through systematic review, we analyzed RT dose, fraction size, latency between completion of RT and toxicity, chemotherapy use, age when irradiated, and sex.

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Purpose: Reirradiation is increasingly used in children and adolescents/young adults (AYA) with recurrent primary central nervous system tumors. The Pediatric Normal Tissue Effects in the Clinic (PENTEC) reirradiation task force aimed to quantify risks of brain and brain stem necrosis after reirradiation.

Methods And Materials: A systematic literature search using the PubMed and Cochrane databases for peer-reviewed articles from 1975 to 2021 identified 92 studies on reirradiation for recurrent tumors in children/AYA.

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Pediatric Normal Tissue Effects in the Clinic (PENTEC) seeks to refine quantitative radiation dose-volume relationships for normal-tissue complication probabilities (NTCPs) in survivors of pediatric cancer. This article summarizes the evolution of PENTEC and compares it with similar adult-focused efforts (eg, Quantitative Analysis of Normal Tissue Effects in the Clinic [QUANTEC] and Hypofractionated Treatment Effects in the Clinic [HyTEC]) with respect to content, oversight, support, scope, and methodology of literature review. It then summarizes key organ-specific findings from PENTEC in an attempt to compare NTCP estimates in children versus adults.

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Pediatric Normal Tissue Effects in the Clinic (PENTEC) is an international multidisciplinary effort that aims to summarize normal-tissue toxicity risks based on published dose-volume data from studies of children and adolescents treated with radiation therapy (RT) for cancer. With recognition that children are uniquely vulnerable to treatment-related toxic effects, our mission and challenge was to assemble our group of physicians (radiation and pediatric oncologists, subspecialists), physicists with clinical and modeling expertise, epidemiologists, and other scientists to develop evidence-based radiation dosimetric guidelines, as affected by developmental status and other factors (eg, other cancer therapies and host factors). These quantitative toxicity risk estimates could serve to inform RT planning and thereby improve outcomes.

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Purpose: The Pediatric Normal Tissue Effects in the Clinic (PENTEC) hearing loss (HL) task force reviewed investigations on cochlear radiation dose-response relationships and risk factors for developing HL. Evidence-based dose-response data are quantified to guide treatment planning.

Methods And Materials: A systematic review of the literature was performed to correlate HL with cochlear dosimetry.

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Purpose: The male reproductive task force of the Pediatric Normal Tissue Effects in the Clinic (PENTEC) initiative performed a comprehensive review that included a meta-analysis of publications reporting radiation dose-volume effects for risk of impaired fertility and hormonal function after radiation therapy for pediatric malignancies.

Methods And Materials: The PENTEC task force conducted a comprehensive literature search to identify published data evaluating the effect of testicular radiation dose on reproductive complications in male childhood cancer survivors. Thirty-one studies were analyzed, of which 4 had testicular dose data to generate descriptive scatter plots.

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Purpose: A Pediatric Normal Tissue Effects in the Clinic (PENTEC) analysis of published investigations of central nervous system (CNS) subsequent neoplasms (SNs), subsequent sarcomas, and subsequent lung cancers in childhood cancer survivors who received radiation therapy (RT) was performed to estimate the effect of RT dose on the risk of SNs and the modification of this risk by host and treatment factors.

Methods And Materials: A systematic literature review was performed to identify data published from 1975 to 2022 on SNs after prior RT in childhood cancer survivors. After abstract review, usable quantitative and qualitative data were extracted from 83 studies for CNS SNs, 118 for subsequent sarcomas, and 10 for lung SNs with 4 additional studies (3 for CNS SNs and 1 for lung SNs) later added.

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Purpose: Few reports describe the risks of late ocular toxicities after radiation therapy (RT) for childhood cancers despite their effect on quality of life. The Pediatric Normal Tissue Effects in the Clinic (PENTEC) ocular task force aims to quantify the radiation dose dependence of select late ocular adverse effects. Here, we report results concerning retinopathy, optic neuropathy, and cataract in childhood cancer survivors who received cranial RT.

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Purpose: Kidney injury is a known late and potentially devastating complication of abdominal radiation therapy (RT) in pediatric patients. A comprehensive Pediatric Normal Tissue Effects in the Clinic review by the Genitourinary (GU) Task Force aimed to describe RT dose-volume relationships for GU dysfunction, including kidney, bladder, and hypertension, for pediatric malignancies. The effect of chemotherapy was also considered.

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Purpose: Electronic portal imaging devices (EPIDs) have been widely utilized for patient-specific quality assurance (PSQA) and their use for transit dosimetry applications is emerging. Yet there are no specific guidelines on the potential uses, limitations, and correct utilization of EPIDs for these purposes. The American Association of Physicists in Medicine (AAPM) Task Group 307 (TG-307) provides a comprehensive review of the physics, modeling, algorithms and clinical experience with EPID-based pre-treatment and transit dosimetry techniques.

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Background: Screening guidelines for childhood cancer survivors treated with radiation currently rely on broad anatomic irradiated regions (IR) to determine risk for late effects. However, contemporary radiotherapy techniques use volumetric dosimetry (VD) to define organ-specific exposure, which supports more specific screening recommendations that could be less costly.

Patients And Methods: This was a cross-sectional study of 132 patients treated with irradiation at Children's Hospital Los Angeles from 2000 to 2016.

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Purpose: This study evaluates the quality of plans used for the treatment of patients in the Children's Oncology Group study ACNS1123. Plan quality is quantified based on a scoring system specific to the protocol. In this way, the distribution of plan quality scores is determined that can be used to identify plan quality issues for this study and for future plan quality improvement.

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Purpose: We describe the methods used to estimate the accuracy of dosimetric data found in literature sources used to construct the Pediatric Normal Tissue Effects in the Clinic (PENTEC) dose-response models, summarize these findings of each organ-specific task force, describe some of the dosimetric challenges and the extent to which these efforts affected the final modeling results, and provide guidance on the interpretation of the dose-response results given the various dosimetric uncertainties.

Methods And Materials: Each of the PENTEC task force medical physicists reviewed all the journal articles used for dose-response modeling to identify, categorize, and quantify dosimetric uncertainties. These uncertainties fell into 6 broad categories.

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Background: Radiation therapy normal tissue dose constraints are critical when treating pediatric patients. However, there is limited evidence supporting proposed constraints, which has led to variations in constraints over the years. In this study, we identify these variations in dose constraints within pediatric trials both in the United States and in Europe used in the past 30 years.

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Purpose: Radiation-induced cerebrovascular toxicity is a well-documented sequelae that can be both life-altering and potentially fatal. We performed a meta-analysis of the relevant literature to create practical models for predicting the risk of cerebral vasculopathy after cranial irradiation.

Methods And Materials: A literature search was performed for studies reporting pediatric radiation therapy (RT) associated cerebral vasculopathy.

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Objectives: The Pediatric Normal Tissue Effects in the Clinic (PENTEC) pulmonary task force reviewed dosimetric and clinical factors associated with radiation therapy (RT)-associated pulmonary toxicity in children.

Methods: Comprehensive search of PubMed (1965-2020) was conducted to assess available evidence and predictive models of RT-induced lung injury in pediatric cancer patients (<21 years old). Lung dose for radiation pneumonitis (RP) was obtained from dose-volume histogram (DVH) data.

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Purpose: The aim of this study was to examine current practice patterns in pediatric total body irradiation (TBI) techniques among COG member institutions.

Methods And Materials: Between November 2019 and February 2020, a questionnaire containing 52 questions related to the technical aspects of TBI was sent to medical physicists at 152 COG institutions. The questions were designed to obtain technical information on commonly used TBI treatment techniques.

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The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States.

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