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 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 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 ◽  
Dose Distribution ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Ipsilateral Lung ◽  
Organ At Risk ◽  
Geometrical Relationship ◽  
Better Than

Abstract BackgroundThis study aimed to evaluate (1) the performance of Auto-Planning module embedded in Pinnnacle treatment planning system (TPS) with 30 left-side breast cancer plans; (2) the dose-distance relations based on overlap volume histogram (OVH) curve.Method30 patients with left-side breast cancer after breast-serving surgery were enrolled in this study. The clinical manual plan (MP) and the automatic plan (AP) were generated by Monaco and Auto-planning module respectively. The geometric relations between organ at risk (OAR) and planning target volume (PTV) of each patient were described by the overlap volume histogram (OVH). The patients were ranked according to the extension distance from PTV at a specific volume on the OVH curve. The MP and AP plans then were ranked to compare with the ranking of the OVH curves. Dosimetric difference between MP and AP plans were evaluated with statistical analysis.ResultThe comparative result shows a higher degree of correlation between AP and OVH curve. For different indicators, the dose distribution of , , in ipsilateral lung is more consistent with the distance-dose relation compared to the dose distribution of in heart. Dosimetric comparison shows a statistically significant improvement in ipsilateral lung and , and in heart of AP plans compared to MP plans. However, the result of ipsilateral lung of MP plans are better than that of AP plans.ConclusionThe overall results of AP plans are superior to MP plans. The dose distribution in AP plans are more consistent with the distance-dose relationship, which was described by OVH. After eliminating the interference of human factors, the AP is able to provide more stable and objective plans for radiotherapy patients.

Evaluation of plan optimisers in prostate VMAT using the dose distribution index

2019 ◽  
Vol 18 (4) ◽  
pp. 323-328 ◽  
Author(s):  
James C. L. Chow ◽  
Runqing Jiang ◽  
Lu Xu
Keyword(s):  
At Risk ◽  
Dose Distribution ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Weighting Factor ◽  
Target Coverage ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Distribution Index

AbstractPurpose:Dose distribution index (DDI) is a treatment planning evaluation parameter, reflecting dosimetric information of target coverage that can help to spare organs at risk (OARs) and remaining volume at risk (RVR). The index has been used to evaluate and compare prostate volumetric modulated arc therapy (VMAT) plans using two different plan optimisers, namely photon optimisation (PO) and its predecessor, progressive resolution optimisation (PRO).Materials and methods:Twenty prostate VMAT treatment plans were created using the PO and PRO in this retrospective study. The 6 MV photon beams and a dose prescription of 78 Gy/39 fractions were used in plans with the same dose–volume criteria for plan optimisation. Dose–volume histograms (DVHs) of the planning target volume (PTV), as well as of OARs such as the rectum, bladder, left and right femur were determined in each plan. DDIs were calculated and compared for plans created by the PO and PRO based on DVHs of the PTV and all OARs.Results:The mean DDI values were 0·784 and 0·810 for prostate VMAT plans created by the PO and PRO, respectively. It was found that the DDI of the PRO plan was about 3·3% larger than the PO plan, which means that the dose distribution of the target coverage and sparing of OARs in the PRO plan was slightly better. Changing the weighting factors in different OARs would vary the DDI value by ∼7%. However, for plan comparison based on the same set of dose–volume criteria, the effect of weighting factor can be neglected because they were the same in the PO and PRO.Conclusions:Based on the very similar DDI values calculated from the PO and PRO plans, with the DDI value in the PRO plan slightly larger than that of the PO, it may be concluded that the PRO can create a prostate VMAT plan with slightly better dose distribution regarding the target coverage and sparing of OARs. Moreover, we found that the DDI is a simple and comprehensive dose–volume parameter for plan evaluation considering the target, OARs and RVR.

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.

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