scholarly journals Comparison of non-coplanar optimization of static beams and arc trajectories for intensity-modulated treatments of meningioma cases

2021 ◽  
Author(s):  
Tiago Ventura ◽  
Humberto Rocha ◽  
Brigida da Costa Ferreira ◽  
Joana Dias ◽  
Maria do Carmo Lopes
Keyword(s):  
Trajectory Optimization ◽  
Graphical Method ◽  
Plan Quality ◽  
Quality Improvements ◽  
Beam Angle ◽  
Beam Direction ◽  
Dose Distributions ◽  
Plan Generation ◽  
Beam Angle Optimization ◽  
Delivery Technique

AbstractTwo methods for non-coplanar beam direction optimization, one for static beams and another for arc trajectories, were proposed for intracranial tumours. The results of the beam angle optimizations were compared with the beam directions used in the clinical plans. Ten meningioma cases already treated were selected for this retrospective planning study. Algorithms for non-coplanar beam angle optimization (BAO) and arc trajectory optimization (ATO) were used to generate the corresponding plans. A plan quality score, calculated by a graphical method for plan assessment and comparison, was used to guide the beam angle optimization process. For each patient, the clinical plans (CLIN), created with the static beam orientations used for treatment, and coplanar VMAT approximated plans (VMAT) were also generated. To make fair plan comparisons, all plan optimizations were performed in an automated multicriteria calculation engine and the dosimetric plan quality was assessed. BAO and ATO plans presented, on average, moderate global plan score improvements over VMAT and CLIN plans. Nevertheless, while BAO and CLIN plans assured a more efficient OARs sparing, the ATO and VMAT plans presented a higher coverage and conformity of the PTV. Globally, all plans presented high-quality dose distributions. No statistically significant quality differences were found, on average, between BAO, ATO and CLIN plans. However, automated plan solution optimizations (BAO or ATO) may improve plan generation efficiency and standardization. In some individual patients, plan quality improvements were achieved with ATO plans, demonstrating the possible benefits of this automated optimized delivery technique.

PO-0913 ON THE EXTENT OF THE BEAM DIRECTION SEARCH SPACE IN COMPUTERIZED NON-COPLANAR BEAM ANGLE OPTIMIZATION FOR IMRT

2012 ◽  
Vol 103 ◽  
pp. S360
Author(s):  
B. Heijmen ◽  
L. Rossi ◽  
S. Breedveld ◽  
P. Voet ◽  
N. Lanconelli ◽  
...  
Keyword(s):  
Search Space ◽  
Beam Angle ◽  
Beam Direction ◽  
Beam Angle Optimization ◽  
Direction Search

On the beam direction search space in computerized non-coplanar beam angle optimization for IMRT—prostate SBRT

2012 ◽  
Vol 57 (17) ◽  
pp. 5441-5458 ◽  
Author(s):  
Linda Rossi ◽  
Sebastiaan Breedveld ◽  
Ben J M Heijmen ◽  
Peter W J Voet ◽  
Nico Lanconelli ◽  
...  
Keyword(s):  
Search Space ◽  
Beam Angle ◽  
Beam Direction ◽  
Beam Angle Optimization ◽  
Direction Search

scholarly journals Beam Angle Optimization for Double-Scattering Proton Delivery Technique Using an Eclipse Application Programming Interface and Convolutional Neural Network

2021 ◽  
Vol 11 ◽  
Author(s):  
Wonjoong Cheon ◽  
Sang Hee Ahn ◽  
Seonghoon Jeong ◽  
Se Byeong Lee ◽  
Dongho Shin ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Convolutional Neural Network ◽  
Optimization Method ◽  
Training Procedure ◽  
Double Scattering ◽  
Beam Angle ◽  
Beam Angle Optimization ◽  
Delivery Technique ◽  
The Mean

To automatically identify optimal beam angles for proton therapy configured with the double-scattering delivery technique, a beam angle optimization method based on a convolutional neural network (BAODS-Net) is proposed. Fifty liver plans were used for training in BAODS-Net. To generate a sequence of input data, 25 rays on the eye view of the beam were determined per angle. Each ray collects nine features, including the normalized Hounsfield unit and the position information of eight structures per 2° of gantry angle. The outputs are a set of beam angle ranking scores (Sbeam) ranging from 0° to 359°, with a step size of 1°. Based on these input and output designs, BAODS-Net consists of eight convolution layers and four fully connected layers. To evaluate the plan qualities of deep-learning, equi-spaced, and clinical plans, we compared the performances of three types of loss functions and performed K-fold cross-validation (K = 5). For statistical analysis, the volumes V27Gy and V30Gy as well as the mean, minimum, and maximum doses were calculated for organs-at-risk by using a paired-samples t-test. As a result, smooth-L1 loss showed the best optimization performance. At the end of the training procedure, the mean squared errors between the reference and predicted Sbeam were 0.031, 0.011, and 0.004 for L1, L2, and smooth-L1 loss, respectively. In terms of the plan quality, statistically, PlanBAO has no significant difference from PlanClinic (P >.05). In our test, a deep-learning based beam angle optimization method for proton double-scattering treatments was developed and verified. Using Eclipse API and BAODS-Net, a plan with clinically acceptable quality was created within 5 min.

scholarly journals A derivative-free multistart framework for an automated noncoplanar beam angle optimization in IMRT

2016 ◽  
Vol 43 (10) ◽  
pp. 5514-5526 ◽  
Author(s):  
Humberto Rocha ◽  
Joana Dias ◽  
Tiago Ventura ◽  
Brígida Ferreira ◽  
Maria do Carmo Lopes
Keyword(s):  
Beam Angle ◽  
Beam Angle Optimization ◽  
Derivative Free

scholarly journals MR-Linac Radiotherapy – The Beam Angle Selection Problem

2021 ◽  
Vol 11 ◽  
Author(s):  
Rik Bijman ◽  
Linda Rossi ◽  
Tomas Janssen ◽  
Peter de Ruiter ◽  
Baukelien van Triest ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Large Scale ◽  
Volumetric Modulated Arc Therapy ◽  
Patient Specific ◽  
Systematic Research ◽  
Plan Quality ◽  
Beam Angle ◽  
Clinical Workflow ◽  
Model Case ◽  
Angle Class

BackgroundWith the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case.Materials and Methods23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared.ResultsFor x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS.ConclusionsComputer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.

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