scholarly journals Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy

2016 ◽  
Vol 50 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Primoz Petric ◽  
Robert Hudej ◽  
Noora Al-Hammadi ◽  
Barbara Segedin
Keyword(s):  
Cervical Cancer ◽  
At Risk ◽  
Organs At Risk ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Analysis Tool ◽  
Contour Analysis ◽  
Characteristic Curves ◽  
Density Mapping

Abstract Background Standard applicators for cervical cancer Brachytherapy (BT) do not always achieve acceptable balance between target volume and normal tissue irradiation. We aimed to develop an innovative method of Target-volume Density Mapping (TDM) for modelling of novel applicator prototypes with optimal coverage characteristics. Patients and methods. Development of Contour-Analysis Tool 2 (CAT-2) software for TDM generation was the core priority of our task group. Main requests regarding software functionalities were formulated and guided the coding process. Software validation and accuracy check was performed using phantom objects. Concepts and terms for standardized workflow of TDM post-processing and applicator development were introduced. Results CAT-2 enables applicator-based co-registration of Digital Imaging and Communications in Medicine (DICOM) structures from a sample of cases, generating a TDM with pooled contours in applicator-eye-view. Each TDM voxel is assigned a value, corresponding to the number of target contours encompassing that voxel. Values are converted to grey levels and transformed to DICOM image, which is transported to the treatment planning system. Iso-density contours (IDC) are generated as lines, connecting voxels with same grey levels. Residual Volume at Risk (RVR) is created for each IDC as potential volume that could contain organs at risk. Finally, standard and prototype applicators are applied on the TDM and virtual dose planning is performed. Dose volume histogram (DVH) parameters are recorded for individual IDC and RVR delineations and characteristic curves generated. Optimal applicator configuration is determined in an iterative manner based on comparison of characteristic curves, virtual implant complexities and isodose distributions. Conclusions Using the TDM approach, virtual applicator prototypes capable of conformal coverage of any target volume, can be modelled. Further systematic assessment, including studies on clinical feasibility, safety and effectiveness are needed before routine use of novel prototypes can be considered.

scholarly journals Result Analysis Of Treatment Planning System Between 3-Dimensional Conformal Radiation Therapy Technique And Intensity Modulated Radiation Therapy Technique In Nasopharyngeal Cancer Cases

2017 ◽  
Vol 8 (1) ◽  
pp. 29-34
Author(s):  
Nursama Heru Apriantoro ◽  
Bambang Sutrisno Wibowo ◽  
Muhammad Irsal ◽  
Prima Chintya Delsi Kasih
Keyword(s):  
At Risk ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Nasopharyngeal Cancer ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Homogeneity Index ◽  
Therapy Technique ◽  
3D Crt

This study aims to analyze the difference in results between TPS 3D-CRT radiotherapy irradiation technique and IMRT radiotherapy irradiation technique in nasopharyngeal cancer cases based on the doses received by the target volume and organs at risk and results of isodosis curve which include the value of the index conformity and homogeneity index value. Type of this research is quantitative experimental method. As for the population was taken in 10 patients consisting of 5 male and 5 female patients with nasopharyngeal cancer who received radiation therapy with 3D-CRT irradiation technique and IMRT radiation technique. Meaningfully, the results shows that are no difference in the dose received by the target volume, the dose received by organs at risk, and the curve isodose on these two techniques, including index values of conformity and homogeneity index. In conclusion, IMRT radiotherapy irradiation technique for nasopharyngeal cancer is more prioritized than 3DCRT radiotherapy irradiation technique, as the radiotherapy principle can be achieved by using IMRT radiotherapy irradiation technique.

scholarly journals Advantages of 3D-CT Based Conformal Radiotherapy Treatment Planning Over 2D Conventional Tera Six Planning for Cervical Cancer Treatment at Ocean Road Cancer Institute

2020 ◽  
Vol 8 (1) ◽  
pp. 59-68
Author(s):  
Khamis Amour ◽  
Dr. Khamza Maunda ◽  
Dr. Mohamed Mazunga ◽  
Dr. Peane Maleka ◽  
Professor Peter Msaki
Keyword(s):  
Cervical Cancer ◽  
At Risk ◽  
Radiation Therapy ◽  
Cancer Patients ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Planning System ◽  
External Beam Radiation ◽  
Treatment Planning System ◽  
3D Ct

Although External Beam Radiation Therapy (EBRT) is essential tool for the radiation therapy of cervical cancer; only one cancer institute in Tanzania performs 3-Dimensional Conformal Radiation Therapy (3DCRT) Computed Tomography (CT)-based planning. To identify benefits and advantages of 3D-CRT over 2D- conventional radiation therapy (2D-CRT), dosimetric parameters for tumor targets and organs at risk (OARs) were compared between these modalities for 23 cervical cancer patients. 11 cervical cancer patients were CT scanned after proper positioning and immobilization and transferred to Eclipse Treatment Planning System (TPS) for dose planning. The remaining 12 curative intent patients were planned using 2D-CRT system and treatment times were calculated for each patient. From the CT based planning, the minimum dose (D min), maximum dose (D max) and mean dose (D mean) to Planning Target Volume (PTV) and organs at risk (OAR), were compared for each plan. On average, the optimized maximum doses for bladder, rectum, femoral heads, PTV and Gross Tumor Volume (GTV) were 46.56 Gy, 42.65 Gy, 28.76 Gy, 48.56 Gy and 48.53 Gy. For 2D-concentional planning, the dose rate was 75.75 cGy/min and the average treatment time was 1.6075 minutes. This study confirms that 3D CT-based planning is a good choice in the treatment protocol for carcinoma cervix as it delivered a highly homogeneous and conformal plan with superior dose coverage to PTV and better OARs sparing.

scholarly journals Automatic Planning for Nasopharyngeal Carcinoma Based on Progressive Optimization in RayStation Treatment Planning System

2020 ◽  
Vol 19 ◽  
pp. 153303382091571
Author(s):  
Yiwei Yang ◽  
Kainan Shao ◽  
Jie Zhang ◽  
Ming Chen ◽  
Yuanyuan Chen ◽  
...  
Keyword(s):  
At Risk ◽  
Nasopharyngeal Carcinoma ◽  
Organs At Risk ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Homogeneity Index ◽  
Automatic Planning ◽  
The Difference ◽  
Better Than

Objective: To evaluate and quantify the planning performance of automatic planning (AP) with manual planning (MP) for nasopharyngeal carcinoma in the RayStation treatment planning system (TPS). Methods: A progressive and effective design method for AP of nasopharyngeal carcinoma was realized through automated scripts in this study. A total of 30 patients with nasopharyngeal carcinoma with initial treatment was enrolled. The target coverage, conformity index (CI), homogeneity index (HI), organs at risk sparing, and the efficiency of design and execution were compared between automatic and manual volumetric modulated arc therapy (VMAT) plans. Results: The results of the 2 design methods met the clinical dose requirement. The differences in D95 between the 2 groups in PTV1 and PTV2 showed statistical significance, and the MPs are higher than APs, but the difference in absolute dose was only 0.21% and 0.16%. The results showed that the conformity index of planning target volumes (PTV1, PTV2, PTVnd and PGTVnx+rpn [PGTVnx and PGTVrpn]), homogeneity index of PGTVnx+rpn, and HI of PTVnd in APs are better than that in MPs. For organs at risk, the APs are lower than the MPs, and the difference was statistically significant ( P < .05). The manual operation time in APs was 83.21% less than that in MPs, and the computer processing time was 34.22% more. Conclusion: IronPython language designed by RayStation TPS has clinical application value in the design of automatic radiotherapy plan for nasopharyngeal carcinoma. The dose distribution of tumor target and organs at risk in the APs was similar or better than those in the MPs. The time of manual operation in the plan design showed a sharp reduction, thus significantly improving the work efficiency in clinical application.

Dosimetric Evaluation for Various Methods of Combined Radiotherapy of Cervical Cancer

2019 ◽  
Vol 64 (1) ◽  
pp. 45-52
Author(s):  
Е. Сухих ◽  
E. Sukhikh ◽  
Л. Сухих ◽  
L. Sukhikh ◽  
О. Аникеева ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
At Risk ◽  
Total Dose ◽  
Organs At Risk ◽  
Planning System ◽  
Coverage Level ◽  
Second Stage ◽  
60Co Source ◽  
Fraction Dose ◽  
3D Crt

Purpose: Carrying out dosimetric investigation of possibility to replace a traditional combined radiation therapy of cervical cancer by combinations only external irradiation, without change of total course dose and number of fractions. Material and Methods: Eleven patients with a diagnosis of cervical cancer (stages T2bNxM0 and T3NxM0) who received a course of combined radiotherapy (CRT) have been considered in this study. The combination of dose delivery techniques 3D-CRT + high dose rate brachytherapy (HDR) was used as a basic one. The following fractionation regimes for CRT were simulated: external beam RT (EBRT) of the first stage – total dose 50 Gy and fraction dose 2 Gy (25 fractions), the second stage – total dose 28 Gy and fraction dose 7 Gy (4 fractions). Total CRT course dose was 89.7 Gy EQD2. Dosimetric planning of EBRT using conventional radiography and 3D-CRT has been carried out using XIO dosimetry planning system. Dosimetric planning of first-stage EBRT and second-stage EBRT using the VMAT technique has been performed in the Monaco dosimetry planning system. HDR of the second stage has been planned using the HDRplus dosimetric planning system for the Multisource HDR unit with a 60Co source. Results: Coverage of the clinical volume of the tumor using HDR, on average, was equal to 95 % of the prescribed dose at 91.8 % of the volume, 110 % of the dose – 75.7 % of the volume. 60Co + VMAT results in the coverage level 95 % of the dose at 97.1 % of the volume and 110 % of the dose at 2.1 % of the volume. 3D-CRT + VMAT provide the coverage level of 95 % of the dose at 98 % of the volume and 110 % of the dose at 2.6 % of the volume. Using the combination VMAT + VMAT allows achieving the average coverage of the target at the level of 98 % of the dose at 97 % of the volume, 110 % of the dose at 8.8 % of the volume. The maximum dose per volume of the organs at risk equal to 2 cm3 did not exceed their tolerant levels both for the bladder and for the rectum. Conclusion: At present, there is a technical possibility to replace the second stage of CRT cervical cancer by EBRT using the VMAT technique. Implementation of the VMAT technique allows to increase the uniformity of irradiated volume coverage comparing with traditional HDR. While using VMAT technique the tolerant levels of organs at risk are not exceeded.

scholarly journals Application of dose-volume histogram prediction in biologically related models for nasopharyngeal carcinomas treatment planning

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Wufei Cao ◽  
Yongdong Zhuang ◽  
Lixin Chen ◽  
Xiaowei Liu
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Volume Histogram ◽  
Parotid Glands ◽  
Dose Volume ◽  
Dose Sparing

Abstract Purpose In this study, we employed a gated recurrent unit (GRU)-based recurrent neural network (RNN) using dosimetric information induced by individual beam to predict the dose-volume histogram (DVH) and investigated the feasibility and usefulness of this method in biologically related models for nasopharyngeal carcinomas (NPC) treatment planning. Methods and materials One hundred patients with NPC undergoing volumetric modulated arc therapy (VMAT) between 2018 and 2019 were randomly selected for this study. All the VMAT plans were created using the Monaco treatment planning system (Elekta, Sweden) and clinically approved: > 98% of PGTVnx received the prescribed doses of 70 Gy, > 98% of PGTVnd received the prescribed doses of 66 Gy and > 98% of PCTV received 60 Gy. Of these, the data from 80 patients were used to train the GRU-RNN, and the data from the other 20 patients were used for testing. For each NPC patient, the DVHs of different organs at risk were predicted by a trained GRU-based RNN using the information given by individual conformal beams. Based on the predicted DVHs, the equivalent uniform doses (EUD) were calculated and applied as dose constraints during treatment planning optimization. The regenerated VMAT experimental plans (EPs) were evaluated by comparing them with the clinical plans (CPs). Results For the 20 test patients, the regenerated EPs guided by the GRU-RNN predictive model achieved good consistency relative to the CPs. The EPs showed better consistency in PTV dose distribution and better dose sparing for many organs at risk, and significant differences were found in the maximum/mean doses to the brainstem, brainstem PRV, spinal cord, lenses, temporal lobes, parotid glands and larynx with P-values < 0.05. On average, compared with the CPs, the maximum/mean doses to these OARs were altered by − 3.44 Gy, − 1.94 Gy, − 1.88 Gy, 0.44 Gy, 1.98 Gy, − 1.82 Gy and 2.27 Gy, respectively. In addition, significant differences were also found in brainstem and spinal cord for the dose received by 1 cc volume with 4.11 and 1.67 Gy dose reduction in EPs on average. Conclusion The GRU-RNN-based DVH prediction method was capable of accurate DVH prediction. The regenerated plans guided by the predicted EUDs were not inferior to the manual plans, had better consistency in PTVs and better dose sparing in critical OARs, indicating the usefulness and effectiveness of biologically related model in knowledge-based planning.

Volumetric modulated arc therapy: a dosimetric comparison with dynamic IMRT and step-and-shoot IMRT

2019 ◽  
Vol 19 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Payal Raina ◽  
Sudha Singh ◽  
Rajanigandha Tudu ◽  
Rashmi Singh ◽  
Anup Kumar
Keyword(s):  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Delivery Time ◽  
Arc Therapy ◽  
Step And Shoot

AbstractAim:The aim of this study was to compare volumetric modulated arc therapy (VMAT) with dynamic intensity-modulated radiation therapy (dIMRT) and step-and-shoot IMRT (ssIMRT) for different treatment sites.Materials and methods:Twelve patients were selected for the planning comparison study. This included three head and neck, three brain, three rectal and three cervical cancer patients. Total dose of 50 Gy was given for all the plans. Plans were done for Elekta synergy with Monaco treatment planning system. All plans were generated with 6 MV photons beam. Plan evaluation was based on the ability to meet the dose volume histogram, dose homogeneity index, conformity index and radiation delivery time, and monitor unit needs to deliver the prescribed dose.Results:The VMAT and dIMRT plans achieved the better conformity (CI98% = 0·965 ± 0·023) and (CI98% = 0·939 ± 0·01), respectively, while ssIMRT plans were slightly inferior (CI98% = 0·901 ± 0·038). The inhomogeneity in the planning target volume (PTV) was highest with ssIMRT with HI equal to 0·097 ± 0·015 when compared to VMAT with HI equal to 0·092 ± 0·0369 and 0·095 ± 0·023 with dIMRT. The integral dose is found to be inferior with VMAT 105·31 ± 53·6 (Gy L) when compared with dIMRT 110·75 ± 52·9 (Gy L) and ssIMRT 115 38 ± 55·1(Gy L). All the techniques respected the planning objective for all organs at risk. The delivery time per fraction for VMAT was much lower than dIMRT and ssIMRT.Findings:Our results indicate that dIMRT and VMAT provide better sparing of normal tissue, homogeneity and conformity than ssIMRT with reduced treatment delivery time.

scholarly journals Cranial organs at risk delineation: heterogenous practices in radiotherapy planning

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Guillaume Vogin ◽  
Liza Hettal ◽  
Clarisse Bartau ◽  
Juliette Thariat ◽  
Marie-Virginie Claeys ◽  
...  
Keyword(s):  
At Risk ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Brain Structures ◽  
Individual Variability ◽  
Planning System ◽  
Radiotherapy Planning ◽  
Treatment Planning System ◽  
Kappa Index ◽  
Contrast Enhanced Ct

Abstract Background Segmentation is a crucial step in treatment planning that directly impacts dose distribution and optimization. The aim of this study was to evaluate the inter-individual variability of common cranial organs at risk (OAR) delineation in neurooncology practice. Methods Anonymized simulation contrast-enhanced CT and MR scans of one patient with a solitary brain metastasis was used for delineation and analysis. Expert professionals from 16 radiotherapy centers involved in brain structures delineation were asked to segment 9 OAR on their own treatment planning system. As reference, two experts in neurooncology, produced a unique consensual contour set according to guidelines. Overlap ratio, Kappa index (KI), volumetric ratio, Commonly Contoured Volume, Supplementary Contoured Volume were evaluated using Artiview™ v 2.8.2—according to occupation, seniority and level of expertise of all participants. Results For the most frequently delineated and largest OAR, the mean KI are often good (0.8 for the parotid and the brainstem); however, for the smaller OAR, KI degrade (0.3 for the optic chiasm, 0.5% for the cochlea), with a significant discrimination (p < 0.01). The radiation oncologists, members of Association des Neuro-Oncologue d’Expression Française society performed better in all indicators compared to non-members (p < 0.01). Our exercise was effective in separating the different participating centers with 3 of the reported indicators (p < 0.01). Conclusion Our study illustrates the heterogeneity in normal structures contouring between professionals. We emphasize the need for cerebral OAR delineation harmonization—that is a major determinant of therapeutic ratio and clinical trials evaluation.

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