scholarly journals Variation of PTV dose distribution on patient size in prostate VMAT and IMRT: a dosimetric evaluation using the PTV dose–volume factor

2013 ◽  
Vol 13 (2) ◽  
pp. 189-194 ◽  
Author(s):  
James C. L. Chow ◽  
Runqing Jiang ◽  
Daniel Markel
Keyword(s):  
Weight Loss ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Size Reduction ◽  
Photon Beams ◽  
Volume Factor ◽  
Tumour Control ◽  
Dose Volume ◽  
Patient Size

AbstractBackgroundWe propose to use the PTV dose–volume factor (PDVF) to evaluate treatment plans of prostate volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT).PurposePDVF was used to compare the variation of planning target volume (PTV) coverage between VMAT and IMRT because of weight loss of patient.Materials and methodsVMAT and IMRT plans of five patients (prostate volume = 32–86·5 cm3) using the 6 MV photon beams were created with the external contour reduced by depths of 0·5–2 cm to reflect the weight loss. Moreover, integral doses (volume integral of the patient dose) and prostate tumour control probability (TCP) were calculated.ResultsWe found that reduced depth resulted in PDVF decreasing 0·03 ± 4·7 × 10−4 (VMAT) and 0·04 ± 9·7 × 10−3 (IMRT) per cm for patients. The decrease of PDVF or degradation of PTV coverage was found more significant in IMRT plans than VMAT with patient size reduction. The integral dose did not change significantly between VMAT and IMRT, while the prostate TCP increased with an increase of reduced depth.ConclusionWe concluded that PDVF can be successfully used to evaluate the variation of PTV coverage because of weight loss of patient in prostate VMAT and IMRT. Degradation of PTV coverage in prostate VMAT is less significant than IMRT regarding patient size reduction.

Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

2016 ◽  
Vol 15 (3) ◽  
pp. 263-268 ◽  
Author(s):  
James C. L. Chow ◽  
Runqing Jiang ◽  
Alexander Kiciak ◽  
Daniel Markel
Keyword(s):  
Planning Target Volume ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Conformity Index ◽  
Volume Factor ◽  
Dose Volume Histograms ◽  
Intensity Modulated ◽  
Dose Volume ◽  
Arc Therapy

AbstractBackgroundWe demonstrated that our proposed planning target volume (PTV) dose–volume factor (PDVF) can be used to evaluate the PTV dose coverage between the intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans based on 90 prostate patients.PurposePDVF were determined from the prostate IMRT and VMAT plans to compare their variation of PTV dose coverage. Comparisons of the PDVF with other plan evaluation parameters such as D5%, D95%, D99%, Dmean, conformity index (CI), homogeneity index (HI), gradient index (GI) and prostate tumour control probability (TCP) were carried out.Methods and materialsProstate IMRT and VMAT plans using the 6 MV photon beams were created from 40 and 50 patients, respectively. Dosimetric indices (CI, HI and GI), dose–volume points (D5%, D95%, D99% and Dmean) and prostate TCP were calculated according to the PTV dose–volume histograms (DVHs) of the plans. All PTV DVH curves were fitted using the Gaussian error function (GEF) model. The PDVF were calculated based on the GEF parameters.ResultsFrom the PTV DVHs of the prostate IMRT and VMAT plans, the average D99% of the PTV for IMRT and VMAT were 74·1 and 74·5 Gy, respectively. The average prostate TCP were 0·956 and 0·958 for the IMRT and VMAT plans, respectively. The average PDVF of the IMRT and VMAT plans were 0·970 and 0·983, respectively. Although both the IMRT and VMAT plans showed very similar prostate TCP, the dosimetric and radiobiological results of the VMAT technique were slightly better than IMRT.ConclusionThe calculated PDVF for the prostate IMRT and VMAT plans agreed well with other dosimetric and radiobiological parameters in this study. PDVF was verified as an alternative of evaluation parameter in the quality assurance of prostate treatment planning.

A comprehensive evaluation of the quality and complexity of prostate IMRT and VMAT plans generated by an automated inverse planning tool

2021 ◽  
pp. 1-7
Author(s):  
Dean Wilkinson ◽  
Kelly Mackie ◽  
Dean Novy ◽  
Frances Beaven ◽  
Joanne McNamara ◽  
...  
Keyword(s):  
Dose Level ◽  
Comprehensive Evaluation ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Planning Tool ◽  
Inverse Planning ◽  
Dose Planning ◽  
Target Volumes ◽  
Lymph Node Irradiation

Abstract Introduction: The Pinnacle3 Auto-Planning (AP) package is an automated inverse planning tool employing a multi-sequence optimisation algorithm. The nature of the optimisation aims to improve the overall quality of radiotherapy plans but at the same time may produce higher modulation, increasing plan complexity and challenging linear accelerator delivery capability. Methods and materials: Thirty patients previously treated with intensity-modulated radiotherapy (IMRT) to the prostate with or without pelvic lymph node irradiation were replanned with locally developed AP techniques for step-and-shoot IMRT (AP-IMRT) and volumetric-modulated arc therapy (AP-VMAT). Each case was also planned with VMAT using conventional inverse planning. The patient cohort was separated into two groups, those with a single primary target volume (PTV) and those with dual PTVs of differing prescription dose levels. Plan complexity was assessed using the modulation complexity score. Results: Plans produced with AP provided equivalent or better dose coverage to target volumes whilst effectively reducing organ at risk (OAR) doses. For IMRT plans, the use of AP resulted in a mean reduction in bladder V50Gy by 4·2 and 4·7 % (p ≤ 0·01) and V40Gy by 4·8 and 11·3 % (p < 0·01) in the single and dual dose level cohorts, respectively. For the rectum, V70Gy, V60Gy and V40Gy were all reduced in the dual dose level AP-VMAT plans by an average of 2·0, 2·7 and 7·3 % (p < 0·01), respectively. A small increase in plan complexity was observed only in dual dose level AP plans. Findings: The automated nature of AP led to high quality treatment plans with improvement in OAR sparing and minimised the variation in achievable dose planning metrics when compared to the conventional inverse planning approach.

scholarly journals Dosimetric evaluation of the heart and left anterior descending artery dose in radiotherapy for Japanese patients with breast cancer

2019 ◽  
Vol 61 (1) ◽  
pp. 134-139
Author(s):  
Osamu Tanaka ◽  
Kousei Ono ◽  
Takuya Taniguchi ◽  
Chiyoko Makita ◽  
Masayuki Matsuo
Keyword(s):  
Breast Cancer ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Japanese Patients ◽  
Target Volume ◽  
The Other ◽  
High Coverage ◽  
Left Anterior Descending Artery ◽  
Treatment Plans ◽  
Field Static

Abstract Intensity-modulated radiotherapy (IMRT) has been used for breast cancer as well as in field-in-field techniques. Few dosimetric comparison studies have been conducted using IMRT and volumetric modulated arc therapy (VMAT) for Japanese patients. We aimed to study such patients. Thirty-two patients with left-sided breast cancer were enrolled. We conducted the following five treatment plans: two field-static IMRT (2F-S-IMRT), four field-static IMRT (4F-S-IMRT), 40° dual partial arc VMAT (40d-VMAT), 80° dual partial arc VMAT (80d-VMAT) and 210° partial VMAT (210p-VMAT). We evaluated the following: level of coverage of planning target volume (PTV) of 95% for irradiation at a dose of 50 Gy (D95) and the percentage of the heart and left anterior descending artery (LAD) volume that received 10 Gy or more (V10). As a result, the coverage of 40d-VMAT for the prescribed PTV dose of D95 was significantly lower than that of the other treatment plans (P &lt; 0.05). Regarding heart V10 and LAD V10, 2F-S-IMRT, 40d-VMAT and 80d-VMAT showed significantly lower dose than the other treatment plans (P &lt; 0.05). In conclusion, among the five plans, 2F-S-IMRT is recommended for Japanese patients because of high coverage of D95 of PTV, low V10 of the heart and LAD and the monitor unit value was the lowest.

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.

Challenges and Differences in External Radiation Therapy for Retinoblastoma: From Standard Techniques to New Developments

2015 ◽  
Vol 103 (5) ◽  
pp. 438-442
Author(s):  
Ayşe Hiçsönmez ◽  
Yıldız Güney ◽  
Ayşen Dizman ◽  
Bahar Dirican ◽  
Yakup Arslan ◽  
...  
Keyword(s):  
Bone Growth ◽  
External Beam Radiotherapy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Dose Volume Histograms ◽  
Normal Tissues ◽  
Dose Volume ◽  
Significant Difference ◽  
Treatment Plans ◽  
External Radiation Therapy

Aims The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife). Methods Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique. Results All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT. Conclusions This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.

scholarly journals Dosimetry of conformal dynamic arc radiotherapy and intensity modulated radiotherapy in unresectable cholangiocarcinoma

2010 ◽  
Vol 4 (1) ◽  
pp. 131-139
Author(s):  
Thanarpan Peerawong ◽  
Chonlakiet Khorprasert ◽  
Sivalee Suriyapee ◽  
Taweap Sanghangthum ◽  
Isra Israngkul Na Ayuthaya ◽  
...  
Keyword(s):  
Planning Target Volume ◽  
Left Kidney ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Intensity Modulated ◽  
Dose Volume ◽  
Organ At Risk ◽  
The Right ◽  
Upper Abdomen ◽  
Critical Structure

Abstract Background: Radiotherapy in cholangiocrcinoma has to overcome organ tolerance of the upper abdomen. Hi-technology radiotherapy may improve conformity and reduce dose to those organ. Objective: Quantitatively compare the dosimetry of conformal dynamic arc radiotherapy (CD-arcRT) and intensity modulated radiotherapy (IMRT) in unresectable cholangiocarcinoma. Material and methods: Eleven cases of unresectable cholangiocarcinoma were re-planned with IMRT and CDarcRT at King Chulalongkhorn Memorial Hospital between 20 September 2004 and 31 December 2005. Both the planning techniques were evaluated using the dose volume histogram of the planning target volume and organ at risk. The conformation number and dose to critical normal structures were used to determine the techniques. Results: IMRT technique was significantly conformed to the planning target volume than CD-arcRT in term of conformation number. For critical structure, IMRT significantly reduced the radiation dose to liver in terms of mean liver dose, V30Gy and V20Gy of the right kidney. Conclusion: The advantage of IMRT was more conformity and reduced dose to critical structure compared with CD-arcRT, but there was no difference between these techniques in terms of V20Gy of left kidney and maximum dose to the spinal cord.

Dose volume histogram metrics and tumour control probability modelling in locally advanced non-small-cell lung cancer: average intensity dataset versus individual four-dimensional CT phases

2020 ◽  
pp. 1-7
Author(s):  
Cathy Fleming ◽  
Ronan McDermott ◽  
Serena O’Keeffe ◽  
Mary Dunne ◽  
John G. Armstrong ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Locally Advanced ◽  
Target Volume ◽  
Small Cell ◽  
Average Intensity ◽  
Dose Volume Histogram ◽  
Small Cell Lung ◽  
Tumour Control ◽  
Dose Volume

Abstract Aim: This work compares dose-volume constraints (DVCs) and tumour control predictions based on the average intensity projection (AVIP) to those on each phase of the four-dimensional computed tomography. Materials and methods: In this prospective study plans generated on an AVIP for nine patients with locally advanced non-small-cell lung cancer were recalculated on each phase. Dose-volume histogram (DVH) metrics extracted and tumour control probabilities (TCP) were calculated. These were evaluated by Bland–Altman analysis and Pearson Correlation. Results: The largest difference between clinical target volume (CTV) on the individual phases and the internal CTV (iCTV) on the AVIP was seen for the smallest volume. For the planning target volume, the mean of each metric across all phases is well represented by the AVIP value. For most patients, TCPs from individual phases are representative of that on the AVIP. Organ at risk metrics from the AVIP are similar to those seen across all phases. Findings: Utilising traditional DVH metrics on an AVIP is generally valid, however, additional investigation may be required for small target volumes in combination with large motion as the differences between the values on the AVIP and any given phase may be significant.

A Baseline Survey on the Treatment Workflow and Pediatric IGRT Practice Among European Members of the Project-Based Consortium and the Pediatric Radiation Oncology Society (PROS).

2020 ◽  
Author(s):  
Coen A.A. Windmeijer ◽  
Arjan Bel ◽  
Rianne de Jong ◽  
Brian V. Balgobind ◽  
Marianne C. Aznar ◽  
...  
Keyword(s):  
Radiation Oncology ◽  
Best Practice ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Baseline Survey ◽  
Image Guided Radiotherapy ◽  
Treatment Techniques ◽  
Pre Treatment

Abstract Background Image-guided radiotherapy (IGRT) enables high precision tumor treatment with potential for sparing healthy tissues. The value of pediatric IGRT is widely acknowledged, but there is no consensus on ‘best practice’. We aimed to assess clinical pediatric IGRT practice among European members of the Pediatric Radiation Oncology Society (PROS) and members of our project-based consortium.Methods A survey addressing radiotherapy preparation, planning and delivery in seven treatment sites was sent to European PROS members and/or our IGRT project-based consortium (70 institutes). Responses were collected from June-September 2018.Results Of the 42 responding institutes (response rate 60%), 33 indicated to treat children. 28/33 are photon-only institutes, 3/33 are dedicated proton (‘proton-only’) institutes and 2/33 use both. Immobilization includes facial masks (in 100% of brain, craniospinal axis (CSA) and head-and-neck (H&N) treatments), and vacuum cushions (all sites, except brain and H&N). Intensity-modulated radiotherapy and volumetric-modulated arc therapy are most frequently applied ranging from 71%-81% in respectively CSA (20/28), and extremities (21/26), followed by 3D conformal radiotherapy ranging from 36%-69% in respectively H&N (10/28), and extremities (18/26). Isotropic planning target volume (PTV) margins varied widely in brain and abdomen (range, 1-10mm). The use of in-room kilovolt cone-beam computed tomography ranges from 57%-86% in respectively CSA (16/28), and thorax (24/28). Daily online imaging is used by the majority of institutes, ranging from 85%-90% in respectively extremities (22/26) and pelvis (27/30). Offline imaging protocols are used by 14%-21% in respectively H&N (4/28) and thorax (6/28).Conclusions Our survey shows comparable practice in pre-treatment imaging, planning and treatment techniques, and IGRT application among the participating European institutes. However, wide ranges in PTV margin sizes exist, supporting the need to define international ‘best practice’ guidelines for pediatric IGRT, and to aim for consensus on optimal margin definitions in view of available IGRT facilities and workflows among institutes.

scholarly journals Is IMRT or VMAT superior or inferior to 3D conformal therapy in the treatment of lung cancer? A brief literature review

2021 ◽  
pp. 1-5
Author(s):  
Kazi T. Afrin ◽  
Salahuddin Ahmad
Keyword(s):  
Lung Cancer ◽  
Literature Review ◽  
Treatment Time ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Patient Comfort ◽  
Tumour Control ◽  
Intrafraction Motion ◽  
Conformal Therapy ◽  
3D Crt

Abstract Aim: To identify treatment outcome, dose uniformity, treatment time, toxicity among 3D conformal therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) for non-small-cell lung cancer (NSCLC) based on literature review. Methods: A literature search was conducted using PubMed/MEDLINE, BMC—part of Springer Nature, Google Scholar and iMEDPub Ltd with the following keywords for filtering: 3D-CRT, IMRT, VMAT, lung cancer, local control and radiobiology. A total of 14 publications were finally selected for the comparison of 3D-CRT, IMRT and VMAT to determine which technique is superior or inferior among these three. Results: Compared to 3D-CRT, IMRT delivers more precise treatment, has better conformal dose coverage to planning target volume (PTV) that covers gross tumour with microscopic extension, respiratory tumour motion and setup margin. 3D-CRT has large number of limitations: low overall survival (OS), large toxicity, secondary malignancies. Conclusions: It is difficult to choose the best technique for treating NSCLC due to patient conditions and technique availability. A high-precision treatment may improve tumour control probability (TCP) and patient’s quality of life. VMAT, whether superior or not, needs more clinical trials to treat NSCLC and requires longer dose optimisation time with the greatest benefit of rapid treatment delivery, improved patient comfort, reduced intrafraction motion and increased patient throughput compared to IMRT and 3D-CRT.

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