scholarly journals CT-Based Collision Prediction Software for External-Beam Radiation Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu-Jen Wang ◽  
Jia-Sheng Yao ◽  
Feipei Lai ◽  
Jason Chia-Hsien Cheng
Keyword(s):  
Radiation Therapy ◽  
Confusion Matrix ◽  
Large Body ◽  
External Beam Radiation ◽  
True Negative ◽  
Beam Radiation ◽  
Beam Angle Optimization ◽  
Software Models ◽  
Collision Prediction ◽  
Collision Problem

PurposeBeam angle optimization is a critical issue for modern radiotherapy (RT) and is a challenging task, especially for large body sizes and noncoplanar designs. Noncoplanar RT techniques may have dosimetric advantages but increase the risk of mechanical collision. We propose a software solution to accurately predict colliding/noncolliding configurations for coplanar and noncoplanar beams.Materials and MethodsIndividualized software models for two different linear accelerators were built to simulate noncolliding gantry orientations for phantom/patient subjects. The sizes and shapes of the accelerators were delineated based on their manuals and on-site measurements. The external surfaces of the subjects were automatically contoured based on computed tomography (CT) simulations. An Alderson Radiation Therapy phantom was used to predict the accuracy of spatial collision prediction by the software. A gantry collision problem encountered by one patient during initial setup was also used to test the validity of the software. Results: In the comparison between the software estimates and on-site measurements, the noncoplanar collision angles were all predicted within a 5-degree difference in gantry position. The confusion matrix was calculated for each of the two empty accelerator models, and the accuracies were 98.7% and 97.3%. The true positive rates were 97.7% and 96.9%, while the true negative rates were 99.8% and 97.9%, respectively. For the phantom study, the collision angles were predicted within a 5-degree difference. The software successfully predicted the collision problem encountered by the breast cancer patient in the initial setup position and generated shifted coordinates that were validated to correspond to a noncolliding geometry.ConclusionThe developed software effectively and accurately predicted collisions for accelerator-only, phantom, and patient setups. This software may help prevent collisions and expand the range of spatially applicable beam angles.

Combined stereotactic split-course fractionated gamma knife radiosurgery and conventional radiation therapy for unfavorable gliomas: a phase I study

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 37-41 ◽  
Author(s):  
William F. Regine ◽  
Roy A. Patchell ◽  
James M. Strottmann ◽  
Ali Meigooni ◽  
Michael Sanders ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Disease Progression ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
External Beam Radiation ◽  
Low Grade ◽  
Beam Radiation ◽  
Content Type ◽  
Group B ◽  
Fine Print

Object. This investigation was performed to determine the tolerance and toxicities of split-course fractionated gamma knife radiosurgery (FSRS) given in combination with conventional external-beam radiation therapy (CEBRT). Methods. Eighteen patients with previously unirradiated, gliomas treated between March 1995 and January 2000 form the substrate of this report. These included 11 patients with malignant gliomas, six with low-grade gliomas, and one with a recurrent glioma. They were stratified into three groups according to tumor volume (TV). Fifteen were treated using the initial FSRS dose schedule and form the subject of this report. Group A (four patients), had TV of 5 cm3 or less (7 Gy twice pre- and twice post-CEBRT); Group B (six patients), TV greater than 5 cm3 but less than or equal to 15 cm3 (7 Gy twice pre-CEBRT and once post-CEBRT); and Group C (five patients), TV greater than 15 cm3 but less than or equal to 30 cm3 (7 Gy once pre- and once post-CEBRT). All patients received CEBRT to 59.4 Gy in 1.8-Gy fractions. Dose escalation was planned, provided the level of toxicity was acceptable. All patients were able to complete CEBRT without interruption or experiencing disease progression. Unacceptable toxicity was observed in two Grade 4/Group B patients and two Grade 4/Group C patients. Eight patients required reoperation. In three (38%) there was necrosis without evidence of tumor. Neuroimaging studies were available for evaluation in 14 patients. Two had a partial (≥ 50%) reduction in volume and nine had a minor (> 20%) reduction in size. The median follow-up period was 15 months (range 9–60 months). Six patients remained alive for 3 to 60 months. Conclusions. The imaging responses and the ability of these patients with intracranial gliomas to complete therapy without interruption or experiencing disease progression is encouraging. Excessive toxicity derived from combined FSRS and CEBRT treatment, as evaluated thus far in this study, was seen in patients with Group B and C lesions at the 7-Gy dose level. Evaluation of this novel treatment strategy with dose modification is ongoing.

Diode in Vivo Dosimetry for Patients Receiving External Beam Radiation Therapy

10.37206/88 ◽  
2005 ◽  
Author(s):  
Ellen Yorke ◽  
Rodica Alecu ◽  
Li Ding ◽  
Doracy Fontenla ◽  
Andre Kalend ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
External Beam Radiation Therapy ◽  
External Beam Radiation ◽  
In Vivo Dosimetry ◽  
External Beam ◽  
Beam Radiation

Evaluation of set-up errors and estimation of set-up margin during external beam radiation therapy of prostate cancer using electronic portal imaging device (EPID)

2021 ◽  
pp. 1-8
Author(s):  
Daryoush Khoramian ◽  
Soroush Sistani ◽  
Bagher Farhood
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
Target Volume ◽  
External Beam Radiation ◽  
Beam Radiation ◽  
Cancer Radiotherapy ◽  
Imaging Device ◽  
Portal Images ◽  
Set Up ◽  
Prostate Cancer Radiotherapy

Abstract Aim: In radiation therapy, accurate dose distribution in target volume requires accurate treatment setup. The set-up errors are unwanted and inherent in the treatment process. By achieving these errors, a set-up margin (SM) of clinical target volume (CTV) to planning target volume (PTV) can be determined. In the current study, systematic and random set-up errors that occurred during prostate cancer radiotherapy were measured by an electronic portal imaging device (EPID). The obtained values were used to propose the optimum CTV-to-PTV margin in prostate cancer radiotherapy. Materials and methods: A total of 21 patients with prostate cancer treated with external beam radiation therapy (EBRT) participated in this study. A total of 280 portal images were acquired during 12 months. Gross, population systematic (Σ) and random (σ) errors were obtained based on the portal images in Anterior–Posterior (AP), Medio-Lateral (ML) and Superior–Inferior (SI) directions. The SM of CTV to PTV were then calculated and compared by using the formulas presented by the International Commission on Radiation Units and Measurements (ICRU) 62, Stroom and Heijmen and Van Herk et al. Results: The findings showed that the population systematic errors during prostate cancer radiotherapy in AP, ML and SI directions were 1·40, 1·95 and 1·94 mm, respectively. The population random errors in AP, ML and SI directions were 2·09, 1·85 and 2·29 mm, respectively. The SM of CTV to PTV calculated in accordance with the formula of ICRU 62 in AP, ML and SI directions were 2·51, 2·68 and 3·00 mm, respectively. And according to Stroom and Heijmen, formula were 4·23, 5·19 and 5·48 mm, respectively. And Van Herk et al. formula were 4·96, 6·17 and 6·45 mm, respectively. Findings: The SM of CTV to PTV in all directions, based on the formulas of ICRU 62, Stroom and Heijmen and van Herk et al., were equal to 2·73, 4·98 and 5·86 mm, respectively; these values were obtained by averaging the margins in all directions.

Disparities in Patterns of Conventional Versus Stereotactic Body Radiotherapy in the Treatment of Spine Metastasis in the United States

2020 ◽  
pp. 082585972098220
Author(s):  
Ellen Kim ◽  
Shearwood McClelland ◽  
Jerry J. Jaboin ◽  
Albert Attia
Keyword(s):  
United States ◽  
Radiation Therapy ◽  
Private Insurance ◽  
Spinal Metastases ◽  
The United States ◽  
External Beam Radiation ◽  
Beam Radiation ◽  
Cancer Data ◽  
Spine Metastases ◽  
Population Type

Introduction: The improved survival of patients even with metastatic cancer has led to an increase in the incidence of spine metastases, suggesting the need for a more aggressive palliative treatment than conventional external beam radiation therapy (cEBRT). Consequently, spinal stereotactic body radiation therapy (SBRT) has increased in popularity over the past decade. However, there has been no comparison of patterns of usage of cEBRT versus SBRT in the treatment of spinal metastases in the US. Methods: The National Cancer Data Base (NCDB) from 2004-2013 was used for analysis. cEBRT was defined as 30 Gy in 10 fractions, 20 Gy in 5 fractions, or 8 Gy in 1 fraction. SBRT was defined as 25-32 Gy infive5 fractions, 24-32 Gy in 4 fractions, 20-32 Gy in three fractions, 14-32 Gy in 2 fractions, or 14-24 Gy in 1 fraction. Single and multivariable associations between patient demographic and cancer characteristics and type of radiation were performed. Results: From 2004-2013, 23,181 patients with spinal metastases in the United States received cEBRT, while 1,030 received SBRT as part of their first course of treatment. Most patients (88%) received 10 fractions of radiation. Multivariable analysis suggested that non-Medicare or private insurance (adjusted OR 0.4-0.7), African-American race (adjusted OR = 0.8, 95%CI = 0.7-1.0), age 65+ (adjusted OR = 0.8), living in a region with lower population (adjusted OR 0.7), earlier year of diagnosis (OR = 0.9), and receiving treatment in a non-academic/research facility (adjusted OR 0.6) were associated with cEBRT. After controlling for other variables, regional education level was no longer significantly associated with cEBRT. Conclusions: Most patients with spine metastases were treated with cEBRT, usually with 10 fractions. Receipt of SBRT was significantly associated with race, insurance, geography, population, type of treatment facility, and year of diagnosis, even after controlling for other factors. These findings raise questions about disparities in access to and delivery of care that deserve further investigation.

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