scholarly journals Monte Carlo-Based Dose Calculation in Postprostatectomy Image-Guided Intensity Modulated Radiotherapy: A Pilot Study

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Ashley Rankine ◽  
Kirsty Turnbull ◽  
Stuart Greenham ◽  
Thomas P. Shakespeare ◽  
Justin Westhuyzen ◽  
...  
Keyword(s):  
Pilot Study ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Step And Shoot

Step-and-shoot (S&S) intensity-modulated radiotherapy (IMRT) using the XiO treatment planning system (TPS) has been routinely used for patients receiving postprostatectomy radiotherapy (PPRT). After installing the Monaco, a pilot study was undertaken with five patients to compare XiO with Monaco (V2.03) TPS for PPRT with respect to plan quality for S&S as well as volumetric-modulated arc therapy (VMAT). Monaco S&S showed higher mean clinical target volume (CTV) coverage (99.85%) than both XiO S&S (97.98%, P = 0.04) and Monaco VMAT (99.44, P = 0.02). Rectal V60Gy volumes were lower for Monaco S&S compared to XiO (46.36% versus 58.06%, P = 0.001) and Monaco VMAT (46.36% versus 54.66%, P = 0.02). Rectal V60Gy volume was lowest for Monaco S&S and superior to XiO (mean 19.89% versus 31.25%, P = 0.02). Rectal V60Gy volumes were lower for Monaco VMAT compared to XiO (21.09% versus 31.25%, P = 0.02). Other organ-at-risk (OAR) parameters were comparable between TPSs. Compared to XiO S&S, Monaco S&S plans had fewer segments (78.6 versus 116.8 segments, P = 0.02), lower total monitor units (MU) (677.6 MU versus 770.7 MU, P = 0.01), and shorter beam-on times (5.7 min versus 7.6 min, P = 0.03). This pilot study suggests that Monaco S&S improves CTV coverage, OAR doses, and planning and treatment times for PPRT.

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.

Dosimetric Comparison of Static Intensity Modulated Radiotherapy, Dynamic Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Thoracic Esophageal Cancer: A Single Institutional Experience

2020 ◽  
Vol 10 (3) ◽  
pp. 628-632
Author(s):  
Ruihao Wang ◽  
Qingxing Zeng ◽  
Songgui Luo ◽  
Guohui Shen ◽  
Ping Li ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Statistical Significance ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Thoracic Esophageal Cancer ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Delivery Efficiency

The aim of this study was to evaluate the dosimetric variations of static intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiotherapy (dIMRT) and volumetric modulated arc therapy (VMAT) for thoracic esophageal cancer (EC). Ten patients with pathologically-confirmed EC were randomly selected. The Monaco 5.11 treatment planning system was used to design six radiotherapy plans, namely sIMRT with 5 fixedfields (S5) and 7 fixed-fields (S7), dIMRT with 5 fixed-fields (D5) and 7 fixed-fields (D7) and VMAT plan with single arc (VMAT1) and double arc (VMAT2), respectively. The dosimetric parameters were compared among six different plans. The dose to target volumes met the clinical prescription requirements in all six plans. The D5 plan had the lowest dose exposed to the whole lungs, except for V5, which was only 1.7% higher than that in the D7 plan. The low dose to lungs (V5 and V10) in VMAT plans (VMAT1 and VMAT2) were higher than in IMRT plans, but the statistical differences were significant (P < 0.05) only in comparison with dynamic IMRT plans (D5 and D7). The V20 and V30 of lungs in VMAT2 plan were also higher than that in other plans, but the statistical differences were significant (P < 0.05) only in comparison with D5 plan. The doses delivered to the spinal cord and heart showed no statistical significance (P > 0.05). The monitor units (MUs) and treatment time (TT) significantly increased with the increasing number of fields in the same kind of fixed-fields IMRT plans (S5 vs. S7; D5 vs. D7). The MUs in VMAT plans, especially in VMAT2, increased significantly (P < 0.05) when compared with sIMRT and 5-fields dIMRT plans, respectively. VMAT1 plan had the shortest TT and the highest delivery efficiency. For thoracic esophageal cancer, the D5 plan can shorten the TT and improve the delivery efficiency while meeting the dosimetric requirements and sparing the lungs. VMAT can significantly reduce the TT, but at the expense of increasing the dose to lower-dose regions of lungs, which means VMAT plan may not shows obvious dose advantage for thoracic esophageal cancer.

Dose verification of volumetric-modulated arc therapy using one-dimensional and two-dimensional dosimeters

2018 ◽  
Vol 18 (03) ◽  
pp. 304-308
Author(s):  
Jalil ur Rehman ◽  
Zahra Syed ◽  
Ghulam Hussain ◽  
Nisar Ahmad ◽  
H M Noor ul Huda Khan Asghar ◽  
...  
Keyword(s):  
Treatment Plan ◽  
External Beam Radiotherapy ◽  
Volumetric Modulated Arc Therapy ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Convolution Algorithm ◽  
Arc Therapy ◽  
Dose Difference

AbstractPurposeTo verify dose delivery and quality assurance of volumetric-modulated arc therapy (VMAT) for head and neck (H&amp;N) cancer.MethodThe Imaging and Radiation Oncology Core Houston (IROC-H) H&amp;N phantom with thermoluminescent dosimeters (TLDs) and films, were imaged with computed tomography scan and the reconstructed image was transferred to pinnacle treatment planning system (TPS). On TPS, the planning target volume (PTV), secondary target volume (STV) and organ at risk (OAR) were delineated manually and a treatment plan was made. The dose constraints were determined for the concerned organs according to IROC-H prescription. The treatment plan was optimised using adoptive convolution algorithm to improve dose homogeneity and conformity. The dose calculation was performed using C.C Convolution algorithm and a Varian True Beam linear accelerator was used to deliver the treatment plan to the H&amp;N phantom. The delivered radiation dose to the phantom was measured through TLDs and GafChromic external beam radiotherapy 2 (EBT2) films. The dosimetric performance of the VMAT delivery was studied by analysing percent dose difference, isodose line profile and gamma analysis of the TPS-computed dose and linac-delivered doses.ResultThe percent dose difference of 3.8% was observed between the planned and measured doses of TLDs and a 1.5-mm distance to agreement (DTA) was observed by comparing isodose line profiles. Passed the gamma criteria of 3%/3 mm was with good percentages.ConclusionThe dosimetric performance of VMAT delivery for a challenging H&amp;N radiotherapy can be verified using TLDs and films embedded in an anthropomorphic H&amp;N phantom.

Is 5 mm breath-hold window (BHW) sufficient to treat carcinoma left breast patients post-conservative surgery: a comparative study using forward intensity-modulated radiotherapy (FIMRT) and volumetric modulated arc therapy (VMAT)

2020 ◽  
pp. 1-9
Author(s):  
Karthikeyan Kalyanasundaram ◽  
Subramani Vellaiyan
Keyword(s):  
Breathing Pattern ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Conservative Surgery ◽  
Target Volume ◽  
Left Breast ◽  
Breath Hold ◽  
Deep Inspiration ◽  
Intensity Modulated ◽  
Arc Therapy

Abstract Purpose: The purpose of the study was to evaluate the impact of changes in breathing pattern inside the breath-hold window (BHW) during deep inspiration breath hold treatment for carcinoma left breast patients post-conservative surgery. Methods: Ten patients of carcinoma left breast post-conservative surgery were prospectively selected. Three sets of CT plain images were acquired, one with 5 mm deep inspiration BHW (DIBHR) and the other one with 1 mm BHW matching the lower threshold (DIBHL) and the third one with 1 mm BHW matching the upper threshold (DIBHH) as DIBHR. For all patients, forward intensity-modulated radiotherapy (FIMRT) and volumetric modulated arc therapy (VMAT) plans were generated in the 5 mm BHW CT series and the same plan being copy and pasted in other series. Target volume doses and critical structure doses were tabulated. Results: Planning target volume coverage was adequate and no significant differences were found in any CT series. Significant differences noted in average left lung V5%, V10% and V18% doses between DIBHR versus DIBHH (p values = 0·0461, 0·0283 and 0·0213, respectively) and DIBHL versus DIBHH (p values = 0·0434, 0·0484 and 0·0334, respectively) for FIMRT plans and V18% doses in DIBHR versus DIBHH (p = 0·0067) in VMAT. No differences in heart and apex of heart doses were found. Left anterior descending artery (LAD) mean doses were significant in DIBHL versus DIBHR, DIBHR versus DIBHH and DIBHL versus DIBHH (p = 0·0012, 0·0444 and 0·0048, respectively) series for FIMRT plans and DIBHR versus DIBHH and DIBHL versus DIBHH (p = 0·0341, 0·0001) for VMAT plans. Finding: The changes in the breathing pattern inside DIBH window level cause some variation in LAD doses and no other significant differences in any parameters noted, so care should be taken while treating patients with preexisting cardiac conditions.

Effect of translational couch shifts in volumetric modulated arc therapy (VMAT) plans and predicting its impact on daily dose delivery

2017 ◽  
Vol 17 (2) ◽  
pp. 230-243
Author(s):  
Noufal M. Padannayil ◽  
Kallikuzhiyil K. Abdullah ◽  
Pallimanhayil A. R. Subha ◽  
Sanudev Sadanadan
Keyword(s):  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Normal Tissue Complication Probability ◽  
Planning System ◽  
Treatment Planning System ◽  
Equivalent Uniform Dose ◽  
Tumour Control ◽  
Matlab Code ◽  
Arc Therapy ◽  
The Impact

AbstractAimTo evaluate the impact of couch translational shifts on dose–volume histogram (DVH) and radiobiological parameters [tumour control probability (TCP), equivalent uniform dose (EUD) and normal tissue complication probability (NTCP)] of volumetric modulated arc therapy (VMAT) plans and to develop a simple and swift method to predict the same online, on a daily basis.MethodsIn total, ten prostate patients treated with VMAT technology were selected for this study. The plans were generated using Eclipse TPS and delivered using Clinac ix LINAC equipped with a Millennium 120 multileaf collimator. In order to find the effect of systematic translational couch shifts on the DVH and radiobiological parameters, errors were introduced in the clinically accepted base plan with an increment of 1 mm and up to 5 mm from the iso-centre in both positive and negative directions of each of the three axis, x [right–left (R-L)], y [superior–inferior (S-I)] and z [anterior–posterior (A-P)]. The percentages of difference in these parameters (∆D, ∆TCP, ∆EUD and ∆NTCP) were analyzed between the base plan and the error introduced plans. DVHs of the base plan and the error plans were imported into the MATLAB software (R2013a) and an in-house MATLAB code was generated to find the best curve fitted polynomial functions for each point on the DVH, there by generating predicted DVH for planning target volume (PTV), clinical target volume (CTV) and organs at risks (OARs). Functions f(x, vj), f(y, vj) and f(z, vj) were found to represent the variation in the dose when there are couch translation shifts in R-L, S-I and A-P directions, respectively. The validation of this method was done by introducing daily couch shifts and comparing the treatment planning system (TPS) generated DVHs and radiobiological parameters with MATLAB code predicted parameters.ResultsIt was noted that the variations in the dose to the CTV, due to both systematic and random shifts, were very small. For CTV and PTV, the maximum variations in both DVH and radiobiological parameters were observed in the S-I direction than in the A-P or R-L directions. ∆V70 Gy and ∆V60 Gy of the bladder varied more due to S-I shift whereas, ∆V40 Gy, ∆EUD and ∆NTCP varied due to A-P shifts. All the parameters in rectum were most affected by the A-P shifts than the shifts in other two directions. The maximum percentage of deviation between the TPS calculated and MATLAB predicted DVHs of plans were calculated for targets and OARs and were found to be less than 0·5%.ConclusionThe variations in the parameters depend upon the direction and magnitude of the shift. The DVH curves generated by the TPS and predicted by the MATLAB showed good correlation.

scholarly journals Comparison of intensity modulated radiotherapy treatment plans between 1.5 T MR-Linac and conventional linac

2020 ◽  
Author(s):  
Shouliang Ding ◽  
Yongbao Li ◽  
Hongdong Liu ◽  
Rui Li ◽  
Bin Wang ◽  
...  
Keyword(s):  
Low Dose ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Skin Dose ◽  
Multiple Tumor ◽  
Intensity Modulated ◽  
Delivery Technique ◽  
Step And Shoot

Abstract Background To assess the dosimetric qualities and usability of planning for 1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various clinical sites in comparison with IMRT plans using a conventional linac.Methods In total of 17 patients with disease sites in the brain, esophagus, lung, rectum and vertebra were re-planned retrospectively for simulated MRL-IMRT using the Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01). Currently, the step-and-shoot (ss) is the only delivery technique for IMRT available on Unity. All patients were treated on an Elekta Versa HD™ with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was recalculated with the same machine and TPS but only changing the technique to step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformity Index, were compared with the clinical plans. The planning usability was measured by the optimization time and the number of Monitor Units (MUs).Results Comparing MRL-IMRT with conventional linac based plans, there were no clinically significant differences between any of the DVH parameters studied for multiple tumor sites. However, MRL-IMRT plans had significantly increased dose to skin and low dose region of normal tissue. Furthermore, MRL-IMRT plans had significantly reduced optimization time by comparing conventional linac based plans. The number of MUs of MRL-IMRT was increased by 23% compared with ss-IMRT, and no difference from dMLC-IMRT.Conclusions Clinically acceptable plans can be achieved with 1.5 T MR-Linac system for multiple tumor sites. The planning efficiency of MRL-IMRT was improved due to the reduced optimization time. However the increase in skin dose and low dose region was also observed in MRL-IMRT plans.

scholarly journals Comparison of Dosimetric Gains Provided by Intensity-Modulated Radiotherapy, Volume-Modulated Arc Therapy, and Helical Tomotherapy for High-Grade Glioma

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Pei Liu ◽  
Gui Liu ◽  
Guihua Wang ◽  
Weibing Zhou ◽  
Yangqing Sun ◽  
...  
Keyword(s):  
At Risk ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiotherapy ◽  
High Grade Glioma ◽  
The Other ◽  
Planning System ◽  
Treatment Planning System ◽  
High Grade ◽  
Intensity Modulated ◽  
Arc Therapy

Purpose. Because of the poor prognosis for high-grade glioma (HGG) patients, it is important to increase the dose of the tumor to improve the efficacy while minimizing the dose of organs at risk (OARs). Thus, we evaluated the potential dosimetric gains of helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT) or volume-modulated arc therapy (VMAT) for high-grade glioma (HGG). Methods. A total of 42 HGG patients were retrospectively selected who had undergone helical tomotherapy; then, IMRT and VMAT plans were generated and optimized for comparison after contouring crucial neuronal structures for neurogenesis and neurocognitive function. IMRT and VMAT were optimized with the Eclipse treatment planning system (TPS) (Version 11.0.31) and HT using TomoTherapy Hi-Art Software (Version 2.0.7) (Accuray, Madison, WI, USA). All three techniques were optimized for simultaneously delivering 60 Gy to planning target volume (PTV) 1 and 50-54 Gy to PTV2. We also analyzed the homogeneity index (HI) and conformity index (CI) of PTVs and organ at risk (OAR) sparing. Results. There was no significant difference in the PTV coverage among IMRT, VMAT, or HT. As for the HI, HT plans (PTV1 HI: 0.09±0.03, PTV2 HI: 0.17±0.05) had the best homogeneity when compared to IMRT plans (PTV1 HI: 0.10±0.04, PTV2 HI: 0.18±0.04) and VMAT plans (PTV1 HI: 0.11±0.03, PTV2 HI: 0.20±0.03). The CI value of HT (PTV1 CI: 0.98±0.03, PTV2: 0.98±0.05) was closest to the optimal value. Except for the IMRT and VMAT groups, there were statistically significant differences between the other two groups of the CI values in both PTV1 and PTV2. The other comparison values were statistically significant except for the optic nerve, and VMAT had the best sparing of the optic chiasm. The mean and max doses of OARs declined significantly in HT. Conclusions. For high-grade glioma patients, HT had superior outcomes in terms of PTV coverage and OAR sparing as compared with IMRT/VMAT.

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