scholarly journals Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

2019 ◽  
Vol 05 (01) ◽  
pp. 24-33
Author(s):  
Manindra Bhushan ◽  
Girigesh Yadav ◽  
Deepak Tripathi ◽  
Lalit Kumar ◽  
Abhinav Dewan ◽  
...  
Keyword(s):  
Photon Energy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Treatment Modalities ◽  
Conformity Index ◽  
P Value ◽  
Carcinoma Cervix ◽  
Intensity Modulated ◽  
Significant Difference

Abstract Introduction To evaluate the dosimetric effect of photon energies on fixed field intensity-modulated radiotherapy (IMRT) and dual arc (DA) planning and to compare the dosimetric differences between conventional IMRT and DA radiotherapy planning. Materials and Methods IMRT and DA plans were generated for 15 patients having cervical cancer using different photon energies. IMRT and DA plans were generated using seven fields and double arcs, respectively. Dosimetric comparison was done in terms of planning target volume (PTV) coverage, sparing of organ at risk (OAR), homogeneity index (HI), conformity index (CI), and monitor units (MUs). Photo-neutron (energy ≤10MV) contribution was not considered for this study. Near region (NR) and far region (FR) were contoured to evaluate the dose deposited in nontarget area. Results No significant difference was observed (p > 0.05) in PTV coverage for conventional IMRT and DA; however, 6 MV yielded significantly better coverage over 15 MV (p < 0.05) for both the treatment modalities. Mean bladder dose was significantly more for conventional IMRT compared with DA. For rectal mean dose, p-value was nonsignificant for IMRT in comparison to DA, while significant difference was observed for change in photon energies for both treatment modalities respectively, except for 10 MV versus 15 MV DA plans. Significant improvements in HI (except 6 MV vs. 10 MV DA), CI (except 6 MV vs. 10 MV IMRT and DA), MUs, NR, and FR were noted. Conclusion DA generates more conformal, homogenous plans, requires less numbers of MUs, and deposits fewer doses to NR and FR regions of nontarget tissues in comparison to conventional IMRT. Although increase in photon energy for IMRT and DA plans reduces numbers of MUs and dose deposited to NR and FR regions, yet the choice for treatment of carcinoma cervix remains 6 MV due to production of photo-neutrons at higher energies.

scholarly journals Variations in inter-observer contouring and its impact on dosimetric and radiobiological parameters for intensity-modulated radiotherapy planning in treatment of localised prostate cancer

2008 ◽  
Vol 7 (2) ◽  
pp. 77-88 ◽  
Author(s):  
Anup Kumar Bhardwaj ◽  
T.S. Kehwar ◽  
S.K. Chakarvarti ◽  
Goda Jayant Sastri ◽  
A.S. Oinam ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Tumour Volume ◽  
Normal Tissue Complication Probability ◽  
Radiotherapy Planning ◽  
Conformity Index ◽  
Tumour Control ◽  
Intensity Modulated ◽  
Tumour Control Probability ◽  
Significant Difference

AbstractInter-observer variations in contouring and their impacts on dosimetric and radiobiological parameters in intensity-modulated radiotherapy (IMRT) treatment for localised prostate cancer patients were investigated. Four observers delineated the gross tumour volume (GTV) (prostate and seminal vesicles), bladder and rectum for nine patients. Contouring done by radiologist was considered as gold standard for comparison purposes and for IMRT plan optimisation. Maximum average variations in contoured prostate, bladder and rectum volumes were 3% (SD = 8.4), 2.5% (SD = 4.12) and 13.2% (SD = 6.77), respectively. The average conformity index for standard contouring set (observer A) was 0.85 (SD = 0.028) and statistically significant differences were observed for observers A–B (p = 0.008), A–C (p = 0.006) and A–D (p = 0.011). Average values of normal tissue complication probability for bladder and rectum for observer A were 0.361% (SD = 0.036) and 1.59% (SD = 0.14). Maximum average tumour control probability was 99.94% (SD = 0.035) and statistically significant difference was observed for observers A–B (p = 0.037) and observers A–C (p = 0.01). Inter-observer contouring variations have significant impact on dosimetric and radiobiological outcome in IMRT treatment planning. So accurate contouring of tumour and normal organs is a fundamental prerequisite to make good correlation between calculated and clinical observed results.

scholarly journals Short-term efficacy comparison between helical tomotherapy and intensity-modulated radiotherapy in patients with locally advanced nasopharyngeal carcinoma

2020 ◽  
Author(s):  
Zhen Cui ◽  
Jia Liu ◽  
Qiaoyu Sun ◽  
Chaoge Wang ◽  
Meifang Fang ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Planning Target Volume ◽  
Helical Tomotherapy ◽  
Locally Advanced ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Short Term ◽  
Intensity Modulated ◽  
Significant Difference ◽  
Better Than

Abstract Background: To evaluate short-term safety and efficacy of helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC).Methods: Retrospective analysis of locally advanced nasopharyngeal carcinoma treated with radiotherapy and concurrent platinum based neoadjuvant chemotherapy (cisplatin 80 mg/m2 every 3 weeks for 1 cycle) in our hospital from February 2017 to October 2019, including 70 patients in HT group and 70 in IMRT group. The target area of ​​the tumor was delineated by magnetic resonance (MRI) imaging. The prescription doses delivered to the gross tumor volume (pGTVnx) and positive lymph nodes (pGTVnd), the high risk planning target volume (PTV1), and the low risk planning target volume (PTV2), were 69.96 Gy, 66-70 Gy, 60 Gy and 50-54 Gy, in 33 fractions, respectively. Acute reactions were evaluated according to the RTOG/EORTC criteria, whereas the therapeutic efficacy was assessed according to RECTST version 1.1 criteria in a 3-months period.Results: The CI of PGTVnx, PGTVnd, PTV1 and PTV2, and HI of PGTVnx, PTV1 and PTV2 in HT group was significantly better than those in IMRT group. The OAR Dmax and Dmean in HT group were better than those in IMRT group with a significant difference (all p <0.05). Patients in the HT group were significantly better than those in the IMRT group in the protection of acute parotid gland injury and hearing damage (p <0.05), but not other acute adverse reaction. No significant difference was found on the short-term efficacy illustrated by ORR between HT group and IMRT group (x2 = 0.119; p = 0.730).Conclusions: Compared with IMRT, HT has better radiophysical-related dosimetric advantages in radiotherapy for locally advanced nasopharyngeal carcinoma. Despite similar on short-term effects, HT has lower incidence of adverse reactions than IMRT.

scholarly journals Volumetric Modulated Arc Therapy for Head and Neck Cancer: A Dosimetric and Treatment Planning Comparison with Intensity Modulated Radiotherapy Techniques

2021 ◽  
Author(s):  
Brijesh Goswami ◽  
Suresh Yadav ◽  
Rakesh Kumar Jain ◽  
Pradeep Goswami
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Patient Comfort ◽  
Conformity Index ◽  
P Value ◽  
Target Coverage ◽  
Treatment Technique ◽  
Intensity Modulated

Introduction: Traditional Intensity Modulated Radiotherapy (IMRT) techniques used many beam angles; the result of this is significant increase in beam on time as well as Monitor Units (MU) also. Due to all of these there is a need of faster treatment modality to increase the patient comfort and lesser organ movement. Aim: To compare the triple arc RapidArc technique with nine field IMRT techniques for different head and neck cancer, focusing on target coverage and dose received by the Organs At Risk (OARs). Materials and Methods: Retrospectively, Computed Tomography (CT) datasets of 20 patients of Squamous Cell Carcinoma (SCC) of the Oro-pharynx and Hypo-pharynx treated during January 2019 to December 2019 were chosen for this study. For every patient, two different treatment plans were created, one by using the triple arc RapidArc technique and others by using nine fixed fields IMRT technique. For Planning Target Volume (PTV), the dose volume parameters D98% and D2% (dose received by the 98%, and 2% of the volume), homogeneity index, and Conformity Index (CI) were evaluated for dosimetric comparison. For OARs, the analysis included the mean dose, the maximum dose expressed as D2%. Additionally, the Beam On Time (BOT) and the number of MUs were analysed. A paired two-tailed t-test was performed to compare the RapidArc technique with the IMRT technique for radiotherapy treatment of different head and neck cancers. The p-value <0.05 was considered for the significance of statistical inferences. Results: Comparable target coverage and better sparing of OARs were achieved with the RapidArc technique in comparison to IMRT. Homogeneity and conformity were also in favour of the RapidArc plan. The dosimetric results with I’MatriXX measurements of RapidArc plans were similar to IMRT plans. All detector points passed 3 mm and 3% gamma criteria for IMRT plans and also for RapidArc plans. Conclusion: RapidArc is a faster and precise treatment technique. RapidArc provides better target coverage with good OARs sparing. Most significant change occurs in the number of MUs and treatment time, which is much lesser in RapidArc.

scholarly journals Dosimetric comparison of jaw tracking in intensity modulated and volumetric modulated arc radiotherapy for carcinoma of cervix

2019 ◽  
Vol 25 (3) ◽  
pp. 155-164
Author(s):  
Karthick Raj Mani ◽  
Muhtasim Aziz Muneem ◽  
Nazneen Sultana ◽  
Tanjina Hossain ◽  
Tabinda Basharat ◽  
...  
Keyword(s):  
Femoral Head ◽  
Dose Reduction ◽  
Low Dose ◽  
Intensity Modulated Radiotherapy ◽  
Conformity Index ◽  
P Value ◽  
Intensity Modulated ◽  
Carcinoma Of Cervix ◽  
Target Volumes ◽  
Volumetric Modulated Arc Radiotherapy

Abstract Aim: To study the dosimetric advantages of the jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric modulated arc radiotherapy (VMAT) for carcinoma of cervix patients. Materials and Methods: We retrospectively selected ten previously treated cervix patients in this study. All the ten patients underwent CT simulation along with immobilization and positional devices. Targets and organ at risks (OARs) were delineated slice by slice for all the patients. All the patients were planned for IMRT and VMAT with intend to deliver 50 Gy in 25 fractions. All the plans were planned with 6 MV photon beam using millennium-120 multi leaf collimator (MLC) using the TrueBeam linear accelerator. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) techniques by keeping the same constraints and priorities for the target volumes and critical structures for a particular patient. For standardization, all the plans were normalized to the target mean of the planning target volume. All the plans were accepted with the criteria of bladder mean dose < 40 Gy and rectum mean dose < 40 Gy without compromising the target volumes. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without jaw tracking for all the patients. Results: The conformity index average of all patients followed by standard deviation (̄x± σ̄x) for JT-IMRT, SJ-IMRT, JT-VMAT and SJ-VMAT were 1.176 ± 0.139, 1.175 ± 0.139, 1.193 ± 0.220 and 1.228 ± 0.192 and homogeneity index were 0.089 ± 0.022, 0.085 ± 0.024, 0.102 ± 0.016 and 0.101 ± 0.016. In low dose volume J,T-IMRT shows a 5.4% (p-value < 0.001) overall reduction in volume receiving at least 5 Gy (V5) compared to SJ-IMRT, whereas 1.2% reduction was observed in V5 volume in JT-VMAT compared to SJ-VMAT. JT-IMRT showed mean reduction in rectum and bladder of 1.34% (p-value < 0.001) and 1.46% (p-value < 0.001) compared to SJ-IMRT, while only 0.30% and 0.03% reduction were observed between JT-VMAT and SJ-VMAT. JT-IMRT plans also showed considerable dose reduction to inthe testine, right femoral head, left femoral head and cauda compared to the SJ-IMRT plans. Conclusion: Jaw tracking resulted in decreased dose to critical structures in IMRT and VMAT plans. But significant dose reductions were observed for critical structures in the JT-IMRT compared to SJ-IMRT technique. In JT-VMAT plans dose reduction to the critical structures were not significant compared to the JT-IMRT due to relatively lesser monitor units in the VMAT plans.

scholarly journals Fluence-map generation for prostate intensity-modulated radiotherapy planning using a deep-neural-network

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hoyeon Lee ◽  
Hojin Kim ◽  
Jungwon Kwak ◽  
Young Seok Kim ◽  
Sang Wook Lee ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Organs At Risk ◽  
Intensity Modulated Radiotherapy ◽  
Radiotherapy Planning ◽  
Conformity Index ◽  
Dose Distributions ◽  
Intensity Modulated ◽  
Map Generation ◽  
Dose Constraints

Abstract A deep-neural-network (DNN) was successfully used to predict clinically-acceptable dose distributions from organ contours for intensity-modulated radiotherapy (IMRT). To provide the next step in the DNN-based plan automation, we propose a DNN that directly generates beam fluence maps from the organ contours and volumetric dose distributions, without inverse planning. We collected 240 prostate IMRT plans and used to train a DNN using organ contours and dose distributions. After training was done, we made 45 synthetic plans (SPs) using the generated fluence-maps and compared them with clinical plans (CP) using various plan quality metrics including homogeneity and conformity indices for the target and dose constraints for organs at risk, including rectum, bladder, and bowel. The network was able to generate fluence maps with small errors. The qualities of the SPs were comparable to the corresponding CPs. The homogeneity index of the target was slightly worse in the SPs, but there was no difference in conformity index of the target, V60Gy of rectum, the V60Gy of bladder and the V45Gy of bowel. The time taken for generating fluence maps and qualities of SPs demonstrated the proposed method will improve efficiency of the treatment planning and help maintain the quality of plans.

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.

scholarly journals Can the Student Outperform the Master? A Plan Comparison Between Pinnacle Auto-Planning and Eclipse knowledge-Based RapidPlan Following a Prostate-Bed Plan Competition

2019 ◽  
Vol 18 ◽  
pp. 153303381985176 ◽  
Author(s):  
April Smith ◽  
Andrew Granatowicz ◽  
Cole Stoltenberg ◽  
Shuo Wang ◽  
Xiaoying Liang ◽  
...  
Keyword(s):  
Intensity Modulated Radiotherapy ◽  
Radiotherapy Planning ◽  
Average Score ◽  
Plan Quality ◽  
Quality Metric ◽  
Intensity Modulated ◽  
Knowledge Based ◽  
Prostate Bed ◽  
Significant Difference ◽  
Integrated Boost

Purpose: Pinnacle Auto-Planning and Eclipse RapidPlan are 2 major commercial automated planning engines that are fundamentally different: Auto-Planning mimics real planners in the iterative optimization, while RapidPlan generates static dose objectives from estimations predicted based on a prior knowledge base. This study objectively compared their performances on intensity-modulated radiotherapy planning for prostate fossa and lymphatics adopting the plan quality metric used in the 2011 American Association of Medical Dosimetrists Plan Challenge. Methods: All plans used an identical intensity-modulated radiotherapy beam setup and a simultaneous integrated boost prescription (68 Gy/56 Gy to prostate fossa/lymphatics). Auto-Planning was used to retrospectively plan on 20 patients, which were subsequently employed as the library to build an RapidPlan model. To compare the 2 engines’ performances, a test set including 10 patients and the Plan Challenge patient was planned by both Auto-Planning (master) and RapidPlan (student) without manual intervention except for a common dose normalization and evaluated using the plan quality metric that included 14 quantitative submetrics ranging over target coverage, spillage, and organ at risk doses. Plan quality metric scores were compared between the Auto-Planning and RapidPlan plans using the Mann-Whitney U test. Results: There was no significant difference between the overall performance of the 2 engines on the 11 test cases ( P = .509). Among the 14 submetrics, Auto-Planning and RapidPlan showed no significant difference on most submetrics except for 2. On the Plan Challenge case, Auto-Planning scored 129.9 and RapidPlan scored 130.3 out of 150, as compared with the average score of 116.9 ± 16.4 (range: 58.2-142.5) among the 125 Plan Challenge participants. Conclusion: Using an innovative study design, an objective comparison has been conducted between 2 major commercial automated inverse planning engines. The 2 engines performed comparably with each other and both yielded plans at par with average human planners. Using a constant-performing planner (Auto-Planning) to train and to compare, RapidPlan was found to yield plans no better than but as good as its library plans.

Helical tomotherapy for advanced esophageal cancer improves target conformity and homogeneity: A comparison with fixed-field intensity-modulated radiotherapy

2015 ◽  
Vol 11 (3) ◽  
pp. 3146-3155
Author(s):  
Luhua Wang
Keyword(s):  
Esophageal Cancer ◽  
Field Intensity ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiotherapy ◽  
Matched Pair ◽  
Conformity Index ◽  
Target Coverage ◽  
Advanced Esophageal Cancer ◽  
Fixed Field ◽  
Intensity Modulated

Purpose: To evaluate the usefulness of helical tomotherapy (HT) in the treatment of advanced esophageal cancer (EC) and compare target homogeneity, conformity and normal tissue doses between HT and fixed-field intensity-modulated radiotherapy (ff-IMRT).Methods: In all, 23 patients with cT3-4N0-1M0-1a thoracic EC (upper esophagus, 9 patients; middle esophagus, 6; distal esophagus, 6 and esophagogastric junction, 2) who were treated with ff-IMRT (60 Gy in 30 fractions) were re-planned for HT and ff-IMRT with the same clinical require­ments. Comparisons were performed using the Wilcoxon matched-pair signed-rank test.Results: Compared with ff-IMRT, HT significantly reduced the homogeneity index for thoracic, upper, middle and distal ECs by 38%, 31%, 36% and 33%, respectively (P < 0.05). The conformity index was increased by HT for thoracic, upper and middle ECs by 9%, 9% and 18%, respectively (P < 0.05). Target coverage was improved by 1% with HT (P < 0.05). The mean lung dose was significantly reduced by HT for thoracic and upper ECs (P < 0.05). The V20 (volume receiving at least 20 Gy) and higher dose volumes of the lungs were decreased by HT in all cases, but the differences were significant for thoracic, upper and distal ECs (P < 0.05), with reductions of 2.1%, 3.1% and 2.2%, respectively. HT resulted in a larger lung V5 for thoracic, upper, middle and distal ECs, with increases of 3.5%, 1.5%, 7.2% and 3.2%, respectively. Heart sparing was significantly better with HT than with ff-IMRT in terms of the V30 and V40 for thoracic, upper, middle and distal ECs (P < 0.05).Conclusions: Compared to ff-IMRT, HT provides superior target coverage, conformity and homogeneity, with reduced the volume of high doses to the lungs and heart for advanced EC. HT may be a treatment option for advanced EC, especially upper EC.

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