SU-E-T-287: Dose Verification On the Variation of Target Volume and Organ at Risk in Preradiation Chemotherapy IMRT for Nasopharyngeal Cancer

2015 ◽  
Vol 42 (6Part16) ◽  
pp. 3399-3399
Author(s):  
X Zhang ◽  
L Kong ◽  
J Wang ◽  
W Hu ◽  
Z Chen
Keyword(s):  
At Risk ◽  
Nasopharyngeal Cancer ◽  
Target Volume ◽  
Dose Verification ◽  
Organ At Risk

scholarly journals Impact of Geometric Uncertainties on Dose Distribution During Intensity Modulated Radiotherapy of Head-and-neck Cancer: The Need for a Planning Target Volume and A Planning Organ-at-Risk Volume

2006 ◽  
Vol 13 (3) ◽  
pp. 108-115 ◽  
Author(s):  
O. Ballivy ◽  
W. Parker ◽  
T. Vuong ◽  
G. Shenouda ◽  
H. Patrocinio
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Neck Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Ct Scans ◽  
Target Coverage ◽  
Geometric Uncertainties ◽  
Intensity Modulated ◽  
Organ At Risk

We assessed the effect of geometric uncertainties on target coverage and on dose to the organs at risk (OARS) during intensity-modulated radiotherapy (IMRT) for head-and-neck cancer, and we estimated the required margins for the planning target volume (PTV) and the planning organ-at-risk volume (PRV). For eight headand- neck cancer patients, we generated IMRT plans with localization uncertainty margins of 0 mm, 2.5 mm, and 5.0 mm. The beam intensities were then applied on repeat computed tomography (CT) scans obtained weekly during treatment, and dose distributions were recalculated. The dose–volume histogram analysis for the repeat CT scans showed that target coverage was adequate (V100 ≥ 95%) for only 12.5% of the gross tumour volumes, 54.3% of the upper-neck clinical target volumes (CTVS), and 27.4% of the lower-neck CTVS when no margins were added for PTV. The use of 2.5-mm and 5.0-mm margins significantly improved target coverage, but the mean dose to the contralateral parotid increased from 25.9 Gy to 29.2 Gy. Maximum dose to the spinal cord was above limit in 57.7%, 34.6%, and 15.4% of cases when 0-mm, 2.5-mm, and 5.0-mm margins (respectively) were used for PRV. Significant deviations from the prescribed dose can occur during IMRT treatment delivery for headand- neck cancer. The use of 2.5-mm to 5.0-mm margins for PTV and PRV greatly reduces the risk of underdosing targets and of overdosing the spinal cord.

scholarly journals Determination of effective dose distribution on the target volume of cancer and organ at risk using MCNPX

2021 ◽  
Vol 1943 (1) ◽  
pp. 012050
Author(s):  
A Y Wardaya ◽  
E Setiawati ◽  
F Arianto ◽  
V Richardina ◽  
R Almareanta ◽  
...  
Keyword(s):  
At Risk ◽  
Effective Dose ◽  
Dose Distribution ◽  
Target Volume ◽  
Organ At Risk

scholarly journals Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

2015 ◽  
Vol 92 (5) ◽  
pp. 1053-1059 ◽  
Author(s):  
Elizabeth H. Baldini ◽  
Ross A. Abrams ◽  
Walter Bosch ◽  
David Roberge ◽  
Rick L.M. Haas ◽  
...  
Keyword(s):  
At Risk ◽  
Target Volume ◽  
Retroperitoneal Sarcoma ◽  
Radiation Oncologists ◽  
Organ At Risk

scholarly journals Positional Accuracy of Treating Multiple Versus Single Vertebral Metastases With Stereotactic Body Radiotherapy

2016 ◽  
Vol 16 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Joe H. Chang ◽  
Arnjeet Sangha ◽  
Derek Hyde ◽  
Hany Soliman ◽  
Sten Myrehaug ◽  
...  
Keyword(s):  
At Risk ◽  
Planning Target Volume ◽  
Stereotactic Body Radiotherapy ◽  
Target Volume ◽  
Vertebral Metastases ◽  
Positional Accuracy ◽  
Computed Tomography Images ◽  
Organ At Risk ◽  
The Mean ◽  
Residual Errors

The aim of this study is to determine whether stereotactic body radiotherapy for multiple vertebral metastases treated with a single isocenter results in greater intrafraction errors than stereotactic body radiotherapy for single vertebral metastases and to determine whether the currently used spinal cord planning organ at risk volume and planning target volume margins are appropriate. Intrafraction errors were assessed for 65 stereotactic body radiotherapy treatments for vertebral metastases. Cone beam computed tomography images were acquired before, during, and after treatment for each fraction. Residual translational and rotational errors in patient positioning were recorded and planning organ at risk volume and planning target volume margins were calculated in each direction using this information. The mean translational residual errors were smaller for single (0.4 (0.4) mm) than for multiple vertebral metastases (0.5 (0.7) mm; P = .0019). The mean rotational residual errors were similar for single (0.3° (0.3°) and multiple vertebral metastases (0.3° (0.3°); P = .862). The maximum calculated planning organ at risk volume margin in any direction was 0.83 mm for single and 1.22 for multiple vertebral metastases. The maximum calculated planning target volume margin in any direction was 1.4 mm for single and 1.9 mm for multiple vertebral metastases. Intrafraction errors were small for both single and multiple vertebral metastases, indicating that our strategy for patient immobilization and repositioning is robust. Calculated planning organ at risk volume and planning target volume margins were smaller than our clinically employed margins, indicating that our clinical margins are appropriate.

scholarly journals Evaluation of dose-volume histogram prediction for organ-at risk and planning target volume based on machine learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sheng xiu Jiao ◽  
Ming li Wang ◽  
Li xin Chen ◽  
Xiao-wei Liu
Keyword(s):  
Rectal Cancer ◽  
Planning Target Volume ◽  
Maximum Dose ◽  
Nasopharyngeal Cancer ◽  
Target Volume ◽  
Dose Volume Histogram ◽  
Dose Volume ◽  
Significant Difference ◽  
Organ At Risk ◽  
Intensity Radiation

AbstractThe purpose of this work is to evaluate the performance of applying patient dosimetric information induced by individual uniform-intensity radiation fields in organ-at risk (OAR) dose-volume histogram (DVH) prediction, and extend to DVH prediction of planning target volume (PTV). Ninety nasopharyngeal cancer intensity-modulated radiation therapy (IMRT) plans and 60 rectal cancer volumetric modulated arc therapy (VMAT) plans were employed in this study. Of these, 20 nasopharyngeal cancer cases and 15 rectal cancer cases were randomly selected as the testing data. The DVH prediction was performed using two methods. One method applied the individual dose-volume histograms (IDVHs) induced by a series of fields with uniform-intensity irradiation and the other method applied the distance-to-target histogram and the conformal-plan-dose-volume histogram (DTH + CPDVH). The determination coefficient R2 and mean absolute error (MAE) were used to evaluate DVH prediction accuracy. The PTV DVH prediction was performed using the IDVHs. The PTV dose coverage was evaluated using D98, D95, D1 and uniformity index (UI). The OAR dose was compared using the maximum dose, V30 and V40. The significance of the results was examined with the Wilcoxon signed rank test. For PTV DVH prediction using IDVHs, the clinical plan and IDVHs prediction method achieved mean UI values of 1.07 and 1.06 for nasopharyngeal cancer, and 1.04 and 1.05 for rectal cancer, respectively. No significant difference was found between the clinical plan results and predicted results using the IDVHs method in achieving PTV dose coverage (D98,D95,D1 and UI) for both nasopharyngeal cancer and rectal cancer (p-values ≥ 0.052). For OAR DVH prediction, no significant difference was found between the IDVHs and DTH + CPDVH methods for the R2, MAE, the maximum dose, V30 and V40 (p-values ≥ 0.087 for all OARs). This work evaluates the performance of dosimetric information of several individual fields with uniform-intensity radiation for DVH prediction, and extends its application to PTV DVH prediction. The results indicated that the IDVHs method is comparable to the DTH + CPDVH method in accurately predicting the OAR DVH. The IDVHs method quantified the input features of the PTV and showed reliable PTV DVH prediction, which is helpful for plan quality evaluation and plan generation.

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.

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