scholarly journals A data-driven method to predict achievability of clinical objectives in IMRT

2021 ◽  
Author(s):  
Vaitheeswaran Ranganathan
Keyword(s):  
Head And Neck ◽  
Treatment Planning ◽  
Region Of Interest ◽  
Target Volume ◽  
Data Driven ◽  
Planning System ◽  
Treatment Planning System ◽  
Geometric Complexity ◽  
Imrt Planning ◽  
Novel Method

Abstract When specifying a clinical objective for a target volume and normal organs/tissues in IMRT planning, the user may not be sure if the defined clinical objective could be achieved by the optimizer. To this end, we propose a novel method to predict the achievability of clinical objectives upfront before invoking the optimization. A new metric called “Geometric Complexity (GC)” is used to estimate the achievability of clinical objectives. Essentially GC is the measure of the number of “unmodulated” beamlets or rays that intersect the Region-of-interest (ROI) and the target volume. We first compute the geometric complexity ratio (GCratio) between the GC of a ROI in a reference plan and the GC of the same ROI in a given plan. The GCratio of a ROI indicates the relative geometric complexity of the ROI as compared to the same ROI in the reference plan. Hence GCratio can be used to predict if a defined clinical objective associated with the ROI can be met by the optimizer for a given case. We have evaluated the proposed method on six Head and Neck cases using Pinnacle3 (version 9.10.0) Treatment Planning System (TPS). Out of total of 42 clinical objectives from six cases accounted in the study, 37 were in agreement with the prediction, which implies an agreement of about 88% between predicted and obtained results. The results indicate the feasibility of using the proposed method in head and neck cases for predicting the achievability of clinical objectives.

scholarly journals Noncoplanar Radiation using Tomotherapy: A Phantom Study

2020 ◽  
Vol 19 ◽  
pp. 153303382094577
Author(s):  
Masahiro Yuasa ◽  
Hiromasa Kurosaki
Keyword(s):  
Image Registration ◽  
Head And Neck ◽  
Treatment Planning ◽  
Planning Target Volume ◽  
Dose Distribution ◽  
Deformable Image Registration ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Computed Tomography Images

Background: There are very few studies on noncoplanar radiation in tomotherapy because deformable image registration is not implemented in the TomoTherapy Planning Station, a treatment planning device used in tomotherapy. This study examined whether noncoplanar radiation can be performed on the head using a tilt-type head and neck fixture and deformable image registration. Methods: Planning target volume spheres with diameters of 2, 3, and 4 cm were set on a head phantom, and computed tomography images were taken at 0° and 40° using a tilt-type head and neck fixture. Irradiation plans were created in the Tomotherapy Planning Station. Noncoplanar radiation was simulated, and the dose volume was evaluated by adding the 0° dose distribution and 40° dose distribution using the deformable image registration of the RayStation treatment planning system. Results: The ratio of the phantom volume to the irradiation dose for 20% to 30% of the planning target volume in noncoplanar radiation was smaller than that for 40% to 90% of the planning target volume in single-section irradiation at 0° or 40°. Conclusions: Noncoplanar radiation on the head region using tomotherapy was possible by using a tilt-type head and neck fixture, and the dose distribution could be evaluated using deformable image registration. This method helps reduce the dose of the organ-at-risk region located slightly away from the planning target volume.

Quality assurance of volumetric-modulated arc therapy head and neck cancer treatment using PRESAGE® dosimeter

2018 ◽  
Vol 17 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Jalil ur Rehman ◽  
Muhammad Isa ◽  
Nisar Ahmad ◽  
H. M. Noor ul Huda Khan Asghar ◽  
Zaheer A. Gilani ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Cancer Treatment ◽  
Head And Neck ◽  
Treatment Planning ◽  
Volumetric Modulated Arc Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Ct Scans ◽  
Arc Therapy ◽  
Calculated Dose

AbstractBackgroundAccurate three-dimensional dosimetry is essential in modern radiotherapy techniques such as volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). In this research work, the PRESAGE® dosimeter was used as quality assurance (QA) tool for VMAT planning for head and neck (H&N) cancer.Material and methodComputer tomography (CT) scans of an Image Radiation Oncology Core (IROC) H&N anthropomorphic phantom with both IROC standard insert and PRESAGE® insert were acquired separately. Both CT scans were imported into the Pinnacle (9.4 version) TPS for treatment planning, where the structures [planning target volume (PTV), organs at risk) and thermoluminescent detectors (TLDs) were manually contoured and used to optimise a VMAT plan. Treatment planning was done using VMAT (dual arc: 182°–178°, 178°–182°). Beam profile comparisons and gamma analysis were used to quantify agreement with film, PRESAGE® measurement and treatment planning system (TPS) calculated dose distribution.ResultsThe average ratio of TLD measured to calculated doses at the four PTV locations in the H&N phantom were between 0·95 to 0·99 for all three VMAT deliveries. Dose profiles were taken along the left–right, the anterior–posterior and superior–inferior axes, and good agreement was found between the PRESAGE® and Pinnacle profile. The mean value of gamma results for three VMAT deliveries in axial and sagittal planes were found to be 94·24 and 93·16% when compared with film and Pinnacle, respectively. The average values comparing the PRESAGE® results and dose values calculated on Pinnacle were observed to be 95·29 and 94·38% in the said planes, respectively, using a 5%/3 mm gamma criteria.ConclusionThe PRESAGE® dose measurements and calculated dose of pinnacle show reasonable agreement in both axial and sagittal planes for complex dual arc VMAT treatment plans. In general, the PRESAGE® dosimeter is found to be a feasible QA tool of VMAT plan for H&N cancer treatment.

Utilising virtual bolus in superficial planning target volume dose optimisation (TomoTherapy): a phantom study

2019 ◽  
Vol 19 (1) ◽  
pp. 65-70
Author(s):  
Gim Chee Ooi ◽  
Iskandar Shahrim Bin Mustafa
Keyword(s):  
Treatment Planning ◽  
Planning Target Volume ◽  
Treatment Plan ◽  
Target Volume ◽  
The Body ◽  
Phantom Study ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Volume Histograms ◽  
Photon Fluence

AbstractAim:This is a phantom study to evaluate the dosimetry effects of using virtual bolus (VB) in TomoTherapy Treatment Planning System (TPS) optimisation for superficial planning target volume (PTV) that extends to the body surface. Without VB, the inverse-planning TPS will continuously boost the photon fluence at the surface of the superficial PTV due to lack of build-up region. VB is used during TPS optimisation only and will not be present in actual treatment delivery.Materials and methods:In this study, a dummy planning target was contoured on a cylindrical phantom which extends to the phantom surface, and VB of various combinations of thickness and density was used in treatment planning optimisation with TomoTherapy TPS. The plans were then delivered with the treatment modality TomoTherapy. Radiochromic films (Gafchromic EBT3) were calibrated and used for dose profiles measurements. TomoTherapy Planned-Adaptive software was used to analyse the delivered Dose-Volume Histograms (DVHs).Results:The use of 2 mm VB was not providing adequate build-up area and was unable to reduce the hot spots during treatment planning and actual delivery. The use of 4 mm VB was able to negate the photon fluence boosting effect by the TPS, and the actual delivery showed relatively small deviations from the treatment plan. The use of 6 mm VB caused significant dose overestimation by the TPS in the superficial regions resulting in insufficient dose coverage delivered.Findings:VB with the combination of 4 mm thickness and 1·0 g/cc density provides the most robust solution for the TomoTherapy TPS optimisation of superficial PTV.

Validation of a deformable image registration produced by a commercial treatment planning system in head and neck

2015 ◽  
Vol 31 (3) ◽  
pp. 219-223 ◽  
Author(s):  
Rafael García-Mollá ◽  
Noelia de Marco-Blancas ◽  
Jorge Bonaque ◽  
Laura Vidueira ◽  
Juan López-Tarjuelo ◽  
...  
Keyword(s):  
Image Registration ◽  
Head And Neck ◽  
Treatment Planning ◽  
Deformable Image Registration ◽  
Planning System ◽  
Treatment Planning System

FDG-PET/CT imaging for staging and definition of tumor volumes in radiation treatment planning in non-small cell lung cancer

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7574-7574 ◽  
Author(s):  
Y. Xu ◽  
S. Ma ◽  
D. Yu ◽  
J. Wang ◽  
L. Zhang ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Fdg Pet ◽  
Radiation Treatment ◽  
Target Volume ◽  
Ct Images ◽  
Planning System ◽  
Treatment Planning System ◽  
Volume Delineation ◽  
Pet Ct ◽  
Fdg Pet Ct

7574 Background: 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) /computed tomography (CT) has a potential improvement for staging and radiation treatment (RT) planning of various tumor sites. But from a clinical standpoint, the open questions are essentially the following: to what extent does PET/CT change the target volume? Can PET/CT reduce inter-observer variability in target volume delineation? We analyzed the use of FDG-PET/ CT images for staging and evaluated the impact of FDG- PET/CT on the radiotherapy volume delineation compared with CT in patients with non-small cell lung cancer (NSCLC) candidates for radiotherapy. Intraobserver variation in delineating tumor volumes was also observed. Methods: Twenty-three patients with stage I-III NSCLC were enrolled in this pilot study and were treated with fractionated RT based therapy with or without chemotherapy. FDG-PET/CT scans were acquired within 2 weeks prior to RT. PET and CT data sets were sent to the treatment planning system Pinnacle through compact disc. The CT and PET images were subsequently fused by means of a dedicated radiation treatment planning system. Gross Tumor Volume (GTV) was contoured by four radiation oncologists respectively on CT (CT-GTV) and PET/CT images (PET/CT-GTV). The resulting volumes were analyzed and compared. Results: For the first phase, two radiation oncologists outlined together the contours achieving a final consensus. Based on PET/CT, changes in TNM categories occurred in 8/23 cases (35%). Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in 12/20 patients (60%) by comparison with CT targeting. The most prominent changes in GTV have been observed in cases with atelectasis. For the second phase was four intraobserver variation in delineating tumor volumes. The mean ratio of largest to smallest CT-based GTV was 2.31 (range 1.01–5.96). The addition of the PET data reduced the mean ratio to 1.46 (range 1.12–2.27). Conclusions: PET/CT fusion images could have a potential impact on both tumor staging and treatment planning. Implementing matched PET/CT reduced observer variation in delineating tumor volumes significantly with respect to CT only. [Table: see text]

scholarly journals Initial Validation of Proton Dose Calculations on SPR Images from DECT in Treatment Planning System

2020 ◽  
Vol 7 (2) ◽  
pp. 51-61
Author(s):  
Sina Mossahebi ◽  
Pouya Sabouri ◽  
Haijian Chen ◽  
Michelle Mundis ◽  
Matthew O'Neil ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Treatment Planning ◽  
Effective Atomic Number ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Relative Electron ◽  
Treatment Plans ◽  
Proton Dose

Abstract Purpose To investigate and quantify the potential benefits associated with the use of stopping-power-ratio (SPR) images created from dual-energy computed tomography (DECT) images for proton dose calculation in a clinical proton treatment planning system (TPS). Materials and Methods The DECT and single-energy computed tomography (SECT) scans obtained for 26 plastic tissue surrogate plugs were placed individually in a tissue-equivalent plastic phantom. Relative-electron density (ρe) and effective atomic number (Zeff) images were reconstructed from the DECT scans and used to create an SPR image set for each plug. Next, the SPR for each plug was measured in a clinical proton beam for comparison of the calculated values in the SPR images. The SPR images and SECTs were then imported into a clinical TPS, and treatment plans were developed consisting of a single field delivering a 10 × 10 × 10-cm3 spread-out Bragg peak to a clinical target volume that contained the plugs. To verify the accuracy of the TPS dose calculated from the SPR images and SECTs, treatment plans were delivered to the phantom containing each plug, and comparisons of point-dose measurements and 2-dimensional γ-analysis were performed. Results For all 26 plugs considered in this study, SPR values for each plug from the SPR images were within 2% agreement with measurements. Additionally, treatment plans developed with the SPR images agreed with the measured point dose to within 2%, whereas a 3% agreement was observed for SECT-based plans. γ-Index pass rates were > 90% for all SECT plans and > 97% for all SPR image–based plans. Conclusion Treatment plans created in a TPS with SPR images obtained from DECT scans are accurate to within guidelines set for validation of clinical treatment plans at our center. The calculated doses from the SPR image–based treatment plans showed better agreement to measured doses than identical plans created with standard SECT scans.

scholarly journals Verifying the accuracy of 3D-CRT dose distributions calculated by the Prowess Panther treatment planning system (TPS) with Monte Carlo (MC) simulation for head-and-neck (H&N) patients

2019 ◽  
Vol 3 (2) ◽  
pp. 90-99
Author(s):  
Luong Thi Oanh ◽  
Duong Thanh Tai ◽  
Hoang Duc Tuan ◽  
Truong Thi Hong Loan
Keyword(s):  
Monte Carlo ◽  
Head And Neck ◽  
Treatment Planning ◽  
Planning System ◽  
Treatment Planning System ◽  
Average Dose ◽  
Monte Carlo Code ◽  
Dose Distributions ◽  
Mc Simulation ◽  
3D Crt

The purpose of this study is to verify and compare the three Dimensional Conformal Radiation Therapy (3D-CRT) dose distributions calculated by the Prowess Panther treatment planning system (TPS) with Monte Carlo (MC) simulation for head-and-neck (H&N) patients. In this study, we used the EGSnrc Monte Carlo code which includes BEAMnrc and DOSXYZnrc programs. Firstly, the clinical 6 MV photon beams form Siemens Primus linear accelerator at Dong Nai General Hospital were simulated using the BEAMnrc. Secondly, the absorbed dose to patients treated by 3D-CRT was computed using the DOSXYZnrc. Finally, the simulated dose distributions were then compared with the ones calculated by the Fast Photon Effective algorithm on the TPS, using the relative dose error comparison and the gamma index using global methods implemented in PTW-VeriSoft with 3%/3 mm. There is a good agreement between the MC and TPS dose. The average gamma passing rates were 92.8% based on the 3%/3 mm. The average dose in the PTV agreed well between the TPS with 0.97% error. MC predict dose was higher than the mean dose to the parotid glands and spinal cord compared to TPS. We have implemented the EGSnrc-based Monte Carlo simulation to verify the 3D-CRT plans generated by Prowess Panther TPS. Our results showed that the TPS agreed with the one of MC.  

scholarly journals Treatment planning for proton therapy: what is needed in the next 10 years?

2020 ◽  
Vol 93 (1107) ◽  
pp. 20190304 ◽  
Author(s):  
Hakan Nystrom ◽  
Maria Fuglsang Jensen ◽  
Petra Witt Nystrom
Keyword(s):  
Treatment Planning ◽  
Proton Therapy ◽  
Computational Thinking ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Biological Efficiency ◽  
Dose Calculation Algorithms ◽  
Computerized Treatment

Treatment planning is the process where the prescription of the radiation oncologist is translated into a deliverable treatment. With the complexity of contemporary radiotherapy, treatment planning cannot be performed without a computerized treatment planning system. Proton therapy (PT) enables highly conformal treatment plans with a minimum of dose to tissues outside the target volume, but to obtain the most optimal plan for the treatment, there are a multitude of parameters that need to be addressed. In this review areas of ongoing improvements and research in the field of PT treatment planning are identified and discussed. The main focus is on issues of immediate clinical and practical relevance to the PT community highlighting the needs for the near future but also in a longer perspective. We anticipate that the manual tasks performed by treatment planners in the future will involve a high degree of computational thinking, as many issues can be solved much better by e.g. scripting. More accurate and faster dose calculation algorithms are needed, automation for contouring and planning is required and practical tools to handle the variable biological efficiency in PT is urgently demanded just to mention a few of the expected improvements over the coming 10 years.

PO-1883 Evaluation of an automated treatment planning system for head and neck treatment

2021 ◽  
Vol 161 ◽  
pp. S1603-S1604
Author(s):  
L. calmels ◽  
D. Sjöström ◽  
Z. Pohl ◽  
P. Sibolt
Keyword(s):  
Head And Neck ◽  
Treatment Planning ◽  
Planning System ◽  
Treatment Planning System
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