scholarly journals A New Approach for a Safe and Reproducible Seeds Positioning for Diffusing Alpha-Emitters Radiation Therapy of Squamous Cell Skin Cancer: A Feasibility Study

Cancers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 240
Author(s):  
Giacomo Feliciani ◽  
Salvatore Roberto Bellia ◽  
Massimo Del Duca ◽  
Giorgio Mazzotti ◽  
Manuela Monti ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
The Novel ◽  
New Approach ◽  
Alpha Emitters ◽  
Novel Approach ◽  
Proper Number ◽  
Source Number

The purpose of this study is to discuss how to use an external radio-opaque template in the Diffusing Alpha-emitters Radiation Therapy (DaRT) technique’s pre-planning and treatment stages. This device would help to determine the proper number of sources for tumour coverage, accounting for subcutaneous invasion and augmenting DaRT safety. The procedure will be carried out in a first phase on a phantom and then applied to a clinical case. A typical DaRT procedure workflow comprises steps like tumour measurements and delineation, source number assessment, and therapy administration. As a first step, an adhesive fiberglass mesh (spaced by 2 mm) tape was applied on the skin of the patient and employed as frame of reference. A physician contoured the lesion and marked the entrance points for the needles with a radio opaque ink marker. According to the radio opaque marks and metabolic uptake the clinical target volume was defined, and with a commercial brachytherapy treatment planning system (TPS) it was possible to simulate and adjust the spatial seeds distribution. After the implant procedure a CT was again performed to check the agreement between simulations and seeds positions. With the procedure described above it was possible to simulate a DaRT procedure on a phantom in order to train physicians and subsequently apply the novel approach on patients, outlining the major issues involved in the technique. The present work innovates and supports DaRT technique for the treatment of cutaneous cancers, improving its efficacy and safety.

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 Can the PTV Volume Be Used to Predict the Better Solution in Manual and Automatic Planning Using the Pinnacle Treatment Planning System for Lung Stereotactic Body Radiation Therapy?

2021 ◽  
Author(s):  
Yanhua Duan ◽  
Yan Shao ◽  
Hua Chen ◽  
Hao Wang ◽  
Hengle Gu ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Roc Analysis ◽  
Stereotactic Body Radiation Therapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Rank Test ◽  
Stereotactic Body Radiation ◽  
Lung Sbrt

Abstract Purpose: The plan quality of the stereotactic body radiation therapy (SBRT) plan is affected by the patient’s planning target volume (PTV). The predictability of PTV volume and cut-off points were investigated to judge the suitability of manual and automatic plans for lung SBRT patients.Methods: The manual and automatic SBRT plans were retrospectively designed using the Pinnacle 16.2 treatment planning system (TPS) for 98 lung cancer patients. the suitability of manual and automatic plans for each patient is comprehensively evaluated. Receiver operating characteristic (ROC) analysis was used to investigate the predictability of PTV volume and determine the cut-off point. Once the cut-off point exists, all patients were divided into two groups according to this cut-off point. The Wilcoxon signed-rank test was performed for the dosimetric comparisons between the two groups. Results: ROC analysis showed that PTV volume (AUC [Area under curve]: 0.918, p= 0.005) has diagnostic power to predict the suitability of manual and automatic plans for lung SBRT patients. The cut-off points of 22.675cc were selected for PTV volume. Regardless of some comparable results, the CI, GI, V10, and V20 of automatic plans were found to be better than manual plans below the cut-off points, and the manual plan is superior to the automatic plan in HI, GI, heart d15cc, V10, V20 above the cut-off points.Conclusion: The PTV volume of cut-off points (22.675cc) are predictive of the suitability of manual and automatic plan using Pinnacle TPS for lung SBRT patients. Automatic plans were recommended for patients with PTV volumes less than 22.675cc, and manual plans can be tried for patients with larger PTV volumes.

HYBRID IMRT RADIATION TECHNIQUE COMPARISON WITH 3D-CRT FOR LEFT-SIDED WHOLE BREAST CANCER

2021 ◽  
Author(s):  
Nina Pavlović ◽  
◽  
Tatjana Miladinović ◽  
Darko Stojanović ◽  
Aleksandar Miladinović ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Radiation Therapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Treatment Technique ◽  
Dose Ratio ◽  
Conformal Radiation Therapy ◽  
3D Crt

To identify the best treatment technique for patients with left-sided breast cancer, we compared plans obtained with a hybrid intensity-modulated radiation therapy (hIMRT) and conventional three- dimensional conformal radiation therapy (3D-CRT). Dosimetric indices for PTVs and OARs were calculated. Also, the dose coverage, homogeneity index, conformity index of the target, and the dose volumes of critical structures were analyzed. A sample of seven patients who were selected randomly treated in University Clinical Center Kragujevac between 2019 and 2020 was selected for the study. Therapy plans for both techniques were made with an ECLIPSE treatment planning system for each patient based on the same images and contours. The hybrid IMRT technique consists of two static opposed tangential fields and four optimized IMRT fields (dose ratio 70:30). For 3D-CRT planning, one isocenter with half-beam blocked tangential fields with wedges was used. All treatment plans were generated with 6 MV photon beam. Hybrid IMRT plans compared to the 3D-CRT resulted in better dose delivered to 95% (D95) of the planning target volume (PTV) and better heterogeneity HI and conformity CI. Protection for critical organs such as the heart, lungs, and contralateral breast is slightly worse than those obtained by 3D-CRT.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

scholarly journals Dosimetric comparison of MR-linac-based IMRT and conventional VMAT treatment plans for prostate cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Vanessa Da Silva Mendes ◽  
Lukas Nierer ◽  
Minglun Li ◽  
Stefanie Corradini ◽  
Michael Reiner ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Coverage ◽  
Treatment Delivery ◽  
Ptv Margin ◽  
Delivery Times ◽  
Low Field ◽  
Treatment Plans

Abstract Background The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Materials and methods 20 PCa patients previously treated with conventional VMAT were considered. For each patient, two different IMRT MRL plans using the low-field MR-linac treatment planning system were created: one with original (orig.) PTV margins and the other with reduced (red.) PTV margins. Dose indices related to target coverage, as well as dose-volume histogram (DVH) parameters for the target and organs at risk (OAR) were compared. Additionally, the estimated treatment delivery times and the number of monitor units (MU) of each plan were evaluated. Results The dose distribution in the high dose region and the target volume DVH parameters (D98%, D50%, D2% and V95%) were similar for all three types of treatment plans, with deviations below 1% in most cases. Both IMRT MRL plans (orig. and red. PTV margins) showed similar homogeneity indices (HI), however worse values for the conformity index (CI) were also found when compared to VMAT. The IMRT MRL plans showed similar OAR sparing when the orig. PTV margins were used but a significantly better sparing was feasible when red. PTV margins were applied. Higher number of MU and longer predicted treatment delivery times were seen for both IMRT MRL plans. Conclusions A comparable plan quality between VMAT and IMRT MRL plans was achieved, when applying the same PTV margin. However, online MR-guided adaptive radiotherapy allows for a reduction of PTV margins. With a red. PTV margin, better sparing of the surrounding tissues can be achieved, while maintaining adequate target coverage. Nonetheless, longer treatment delivery times, characteristic for the IMRT technique, have to be expected.

scholarly journals Dosimetric Studies of Mixed Energy Intensity Modulated Radiation Therapy for Prostate Cancer Treatments

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
K. Abdul Haneefa ◽  
K. K. Shakir ◽  
A. Siddhartha ◽  
T. Siji Cyriac ◽  
M. M. Musthafa ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
High Energy ◽  
Photon Beam ◽  
Planning System ◽  
Treatment Planning System ◽  
Intensity Modulated ◽  
Mixed Beam ◽  
Mixed Field

Dosimetric studies of mixed field photon beam intensity modulated radiation therapy (IMRT) for prostate cancer using pencil beam (PB) and collapsed cone convolution (CCC) algorithms using Oncentra MasterPlan treatment planning system (v. 4.3) are investigated in this study. Three different plans were generated using 6 MV, 15 MV, and mixed beam (both 6 and 15 MV). Fifteen patients with two sets of plans were generated: one by using PB and the other by using CCC for the same planning parameters and constraints except the beam energy. For each patient’s plan of high energy photons, one set of photoneutron measurements using solid state neutron track detector (SSNTD) was taken for this study. Mean percentage of V66 Gy in the rectum is 18.55±2.8, 14.58±2.1, and 16.77±4.7 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mean percentage of V66 Gy in bladder is 16.54±2.1, 17.42±2.1, and 16.94±41.9 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mixed fields neutron contribution at the beam entrance surface is 45.62% less than at 15 MV photon beam. Our result shows that, with negligible neutron contributions, mixed field IMRT has considerable dosimetric advantage.

Evaluation of Auto-Planning for Left-Side Breast Cancer After Breast-Conserving Surgery Based on Geometrical Relationship

2020 ◽  
Author(s):  
Yijiang Li ◽  
Han Bai ◽  
Danju Huang ◽  
Feihu Chen ◽  
Xuhong Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Correlation Coefficient ◽  
Dose Distribution ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Geometric Information ◽  
Ipsilateral Lung ◽  
Geometrical Relationship

Abstract Purpose: This study aimed to evaluate (1) the performance of the Auto-Planning module embedded in the Pinnacle treatment planning system (TPS) with 30 left-side breast cancer plans and (2) the dose-distance correlations between dose-based patients and overlap volume histogram-based (OVH) patients. Method: A total of 30 patients with left-side breast cancer after breast-conserving surgery were enrolled in this study. The clinical manual-planning (MP) and the Auto-Planning (AP) plans were generated by Monaco and by the Auto-Planning module in Pinnacle respectively. The geometric information between organ at risk (OAR) and planning target volume (PTV) of each patient was described by the OVH. The AP and MP plans were ranked to compare with the geometry-based patients from OVH. The Pearson product-moment correlation coefficient (R) was used to describe the correlations between dose-based patients (APs and MPs) and geometry-based patients (OVH). Dosimetric differences between MP and AP plans were evaluated with statistical analysis. Result: The correlation coefficient (mean R = 0.71) indicated that the AP plans have a high correlation with geometry-based patients from OVH, whereas the correlation coefficient (mean R = 0.48) shows a weak correlation between MP plans and geometry-based patients. For different indicators, the dose distribution of V5Gy in the ipsilateral lung (AP: mean R = 0.82; MP: mean R = 0.58) is more relevant to geometry-based patients compared to the dose distribution of in the heart (AP: mean R = 0.4; MP: mean R = 0.19). The dosimetric comparison revealed a statistically significant improvement in ipsilateral lung V5Gy and V10Gy and in the heart V5Gy of AP plans compared to MP plans. Conclusion: The overall results of AP plans were superior to MP plans. The dose distribution in AP plans was more consistent with the distance-dose relationship described by OVH. After eliminating the interference of human factors, the AP was able to provide more stable and objective plans for radiotherapy patients.

A Novel Perspective in the Design of Cable-Driven Systems

2008 ◽  
Author(s):  
Giulio Rosati ◽  
Damiano Zanotto
Keyword(s):  
Systems Design ◽  
The Novel ◽  
End Effector ◽  
New Approach ◽  
Driven Systems ◽  
Working Space ◽  
Novel Approach ◽  
Workspace Analysis ◽  
Workspace Optimization ◽  
Novel Design

This paper deals with a novel approach to the design of cable-driven systems. This kind of robots possesses several desirable features that distinguish them from common manipulators, such as: low-inertia, cost-effectiveness, safety, easy reconfiguration and transportability. One key-issue that arises from the unilateral actuation is the design for workspace optimization. Most previous researches on cable-driven systems design focused their attention on workspace analysis for existing devices. Conversely, we introduce a new approach for improving workspace by design, introducing movable pulley-blocks rather than increasing the number of cables. By properly moving the pulley-blocks, the end-effector can be always maintained in the best part of the working space, thus enhancing robot capabilities without the need for additional cables. Furthermore, the eventuality of cable interference is strongly reduced. In this paper, the novel design concept is applied to different planar point-mass cable-driven robots, with one or more translating pulley-blocks. The maximum feasible isotropic force, along with the power dissipation and the effective mass at the end-effector are employed to compare the performances of different configurations.

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