Inter-operator variability in organs at risk delineation: Their effects on dose-volume histograms

2013 ◽  
Vol 29 ◽  
pp. e39
Author(s):  
D. Llanas ◽  
J. Bézin ◽  
A. Ben Abdennebi ◽  
C. Veres ◽  
D. Lefkopoulos ◽  
...  
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Dose Volume Histograms ◽  
Dose Volume

A deep learning model to predict dose–volume histograms of organs at risk in radiotherapy treatment plans

2020 ◽  
Vol 47 (11) ◽  
pp. 5467-5481
Author(s):  
Zhiqiang Liu ◽  
Xinyuan Chen ◽  
Kuo Men ◽  
Junlin Yi ◽  
Jianrong Dai
Keyword(s):  
At Risk ◽  
Deep Learning ◽  
Organs At Risk ◽  
Learning Model ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Treatment Plans ◽  
Deep Learning Model ◽  
Radiotherapy Treatment

Dose volume histogram analysis for organs at risk when using 6 external beam techniques for radical prostatic irradiation

2000 ◽  
Vol 2 (1) ◽  
pp. 17-25 ◽  
Author(s):  
T. Haycocks ◽  
J. Mui ◽  
H. Alasti ◽  
C. Catton
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Area Under The Curve ◽  
Target Volume ◽  
Dose Volume Histograms ◽  
Treatment Techniques ◽  
Dose Volume ◽  
Femoral Heads ◽  
Curve Method ◽  
Set Up

Ten patients with prostate cancer were each planned with 3 conventional and 3 conformal isocentric treatment techniques to compare the relative radiation doses to the bladder and rectal walls, and femoral head using dose volume histograms (DVH). The DVH were calculated for each organ and each technique, and the plans were ranked using the area under the curve method and also by the relative radiation dose given to specific normal tissue volumes.The results show that for the planning target volume chosen, the 4 field non-coplanar technique delivers the least dose to the bladder, the 6 field coplanar technique delivers the least dose to the rectum and the 3 field oblique technique delivers the least dose to the femoral heads. The 4-field technique with no shielding contributes the most dose to the bladder and rectum and the 6 field coplanar technique contributes the most dose to the femoral heads.No technique was shown to be optimal for all the organs at risk, but both the 6 field and 4 field non-coplanar field arrangements were shown to be superior techniques for minimising both the bladder and rectal dosage. The choice of technique will therefore depend on other factors such as the total prescribed dose, the ease of set-up and the ease of verification of isocentre reproducibility.

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.

Predicting dose-volume histograms for organs-at-risk in IMRT planning

2012 ◽  
Vol 39 (12) ◽  
pp. 7446-7461 ◽  
Author(s):  
Lindsey M. Appenzoller ◽  
Jeff M. Michalski ◽  
Wade L. Thorstad ◽  
Sasa Mutic ◽  
Kevin L. Moore
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Imrt Planning

Volumetric modulated arc therapy versus 3D conformal radiotherapy for selected childhood neoplasms

2014 ◽  
Vol 14 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Marzanna Chojnacka ◽  
Anna Zygmuntowicz-Piętka ◽  
Anna Semaniak ◽  
Katarzyna Pędziwiatr ◽  
Ryszard Dąbrowski ◽  
...  
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
High Dose ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Arc Therapy ◽  
Childhood Neoplasms

AbstractAimThe comparative study of the plan quality between volumetric modulated arc therapy (VMAT) and 3D conformal therapy (3DCRT) for the treatment of selected representative childhood neoplasms was performed.Materials and methodsDuring the year 2013, 44 children with neoplasms were irradiated using VMAT. The 3DCRT plans were created retrospectively and compared with the VMAT plans for four tumour locations. The conformity parameters, dose volume histograms for target volume and organs at risk, number of monitor units and time used to deliver the single fraction were evaluated and compared for each plan. Additionally, for patients with brain tumour the comparison of different arcs configuration was made.ResultsVMAT modality presented the superiority over older conformal methods with regard to the improvement in the dose conformity and normal tissue sparing. The noncoplanar arcs arrangement was beneficial in the decrease of high-dose volume and the protection of the organs at risk located oppositely to the target volume.FindingsVMAT could be preferred technique for treating childhood neoplasms, especially when the complex-shaped target volume is localised close to the critical structures. The noncoplanar arcs arrangement could be the method of choice in the reirradiated patients and in these with laterally located brain tumours.

scholarly journals Effective Organs-at-Risk Dose Sparing in Volumetric Modulated Arc Therapy Using a Half-Beam Technique in Whole Pelvic Irradiation

2021 ◽  
Vol 11 ◽  
Author(s):  
Hyunsoo Jang ◽  
Jiyeon Park ◽  
Mark Artz ◽  
Yawei Zhang ◽  
Jacob C. Ricci ◽  
...  
Keyword(s):  
At Risk ◽  
Small Intestine ◽  
Dose Reduction ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Arc Therapy ◽  
Dose Sparing ◽  
Beam Technique

BackgroundAlthough there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)’s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT.MethodsWhile the size of a fully opened field (FF) was decided to entirely include a planning target volume in all beam’s eye view across arc angles, the HF was designed to use half the FF from the isocenter for dose optimization. The left or the right half of the FF was alternatively opened in VMAT-HF using a pair of arcs rotating clockwise and counterclockwise. Dosimetric benefits of VMAT-HF, presented with dose conformity, homogeneity, and dose–volume parameters in terms of modulation complex score, were compared to VMAT optimized using the FF (VMAT-FF). Consequent normal tissue complication probability (NTCP) by reducing the irradiated volumes was evaluated as well as dose–volume parameters with statistical analysis for OAR. Moreover, beam-on time and MLC position precision were analyzed with log files to assess plan deliverability and clinical applicability of VMAT-HF as compared to VMAT-FF.ResultsWhile VMAT-HF used 60%–70% less intensity modulation complexity than VMAT-FF, it showed superior dose conformity. The small intestine and colon in VMAT-HF showed a noticeable reduction in the irradiated volumes of up to 35% and 15%, respectively, at an intermediate dose of 20–45 Gy. The small intestine showed statistically significant dose sparing at the volumes that received a dose from 15 to 45 Gy. Such a dose reduction for the small intestine and colon in VMAT-HF presented a significant NTCP reduction from that in VMAT-FF. Without sacrificing the beam delivery efficiency, VMAT-HF achieved effective OAR dose reduction in dose–volume histograms.ConclusionsVMAT-HF led to deliver conformal doses with effective gastrointestinal-OAR dose sparing despite using less modulation complexity. The dose of VMAT-HF was delivered with the same beam-on time with VMAT-FF but precise MLC leaf motions. The VMAT-HF potentially can play a valuable role in reducing OAR toxicities associated with WPRT.

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