Dosimetric comparison of constant dose rate volumetric modulated arc therapy (CDR-VMAT) and intensity-modulated radiation therapy (IMRT) for gallbladder cancer

2020 ◽  
pp. 1-6
Author(s):  
Varsha R. Gedam ◽  
Anirudh Pradhan
Keyword(s):  
Gallbladder Cancer ◽  
Left Kidney ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Treatment Delivery ◽  
Significant Difference ◽  
Arc Therapy ◽  
Constant Dose ◽  
The Mean ◽  
The Right

Abstract Aim: To study the feasibility of constant dose rate volumetric modulated arc therapy (CDR-VMAT) in radiotherapy for gallbladder cancer by comparing dosimetric parameter suggested by International Commission on Radiation Units and Measurements-83 (ICRU-83) with step and shoot intensity-modulated radiation therapy (SS IMRT). Methods: For this study, we selected 21 post-operative gallbladder cancer patients, which were treated with the IMRT technique from 2016 to 2019. For each patient, we generated SS IMRT plan and CDR-VMAT plan and were dosimetrically compared by parameters suggested by ICRU-83 for PTV. Homogeneity Index (HI) and Conformity Index (CI) were also calculated. For evaluation of Organ at Risk (OAR), we compared the mean doses, volume doses to the right kidney, left kidney, both kidneys combined, liver and max dose to the spinal cord. Monitor units (MUs) and treatment delivery time were also compared. Results: On comparing, we found that CDR-VMAT plans were highly conformed as CI and PCI (CI define by Paddick) were found more (0·98 ± 0·01 vs. 0·97 ± 0·03 and 0·86 ± 0·05 vs. 0·85 ± 0·05) than IMRT plans but not statistically significant. Better dose HI was found for IMRT plans with statistical significant difference (p < 0·001). The tumour coverage was found similar 98·24% and 97·83% for SS IMRT and CDR-VMAT, respectively. For D2%, the maximum dose to PTV was significantly lower in IMRT (p = 0·001). D50% and mean dose to PTV were also comparable to IMRT with no statistically significant difference. The OAR parameters were comparable in both the techniques. The mean doses and volume doses V10, V20 and V30 to the right kidney, left kidney and liver were also comparable with no significant difference (p > 0·05) was noted among them. However, the maximum dose to the spinal cord was significantly less in CDR-VMAT (21·1 Gy vs. 25·1Gy) than SS IMRT with p = 0·006. More MUs were associated with the CDR-VMAT technique, but shorter treatment delivery time than the IMRT technique. Conclusions: On dosimetric comparison of two treatment techniques, we conclude that CDR-VMAT can be a valid option in radiotherapy as it achieved highly conformed dose distribution, comparable tumour coverage and OAR sparing as IMRT technique for gallbladder cancer.

Dosimetric comparison of volumetric-modulated arc therapy and helical tomotherapy for adjuvant treatment of bilateral breast cancer

2020 ◽  
pp. 1-9
Author(s):  
Reena Phurailatpam ◽  
Tabassum Wadasadawala ◽  
Kamalnayan Chauhan ◽  
Subhajit Panda ◽  
Rajiv Sarin
Keyword(s):  
Breast Cancer ◽  
Helical Tomotherapy ◽  
Treatment Time ◽  
Volumetric Modulated Arc Therapy ◽  
Bilateral Breast Cancer ◽  
Whole Body ◽  
Dosimetric Comparison ◽  
Significant Difference ◽  
Arc Therapy ◽  
The Mean

Abstract Purpose: Dosimetric comparison between volumetric-modulated arc therapy (VMAT) and helical tomotherapy (HT) in the treatment of bilateral breast cancer (BBC). Materials and methods: Ten patients treated on HT were selected retrospectively. Dose prescription was 50 Gy in 25 fractions to breast/chest wall and supraclavicular fossa (SCF) while tumour bed was simultaneously boosted to 61 Gy in 25 fractions. VMAT plans were made with four mono-isocentric partial arcs. The monitoring unit (MU) and treatment time were used to quantify the treatment efficiency. Target volumes were compared for homogeneity index (HI), conformity index (CI) while organs at risk (OARs) were compared for relevant dose volumes and integral doses (IDs). Result: For targets, no significant difference is observed between VMAT and HT in CI but VMAT could give better HI. The mean lung dose, V20 and V5 is 10·6 Gy versus 8·4 Gy (p-value 0·03), 12% versus 11·5% (p-value 0·5) and 78·1% versus 43·4% (p-value 0·005), respectively. The mean heart dose, V30 and V5 is 4·9 Gy versus 4·7 Gy (p-value 0·88), 0·5% versus 1·5% (p-value 0·18) and 26·2% versus 22·8% (p-value 0·4). Integral dose (ID) for the whole body and heart are comparable: 289 Gy kg versus 299 Gy kg (p-value 0·24) and 2·9 Gy kg versus 2·8 Gy kg (p-value 0·80). ID for lungs was significantly higher with VMAT: 7·9 Gy kg versus 6·3 Gy kg (p-value 0·03). There is a 53% reduction in treatment time and 78% in MU with VMAT against HT. Conclusion: VMAT can generate clinically acceptable plans comparable to HT for BBC. HT shows better control over low dose spillage in lungs compared to VMAT thereby increasing ID to lungs. VMAT shows better homogeneity and efficient treatment delivery than HT.

Study of Renal Iron Overload by T2* MRI in a Large Cohort of Thalassemia Major Patients

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 5177-5177
Author(s):  
Antonella Meloni ◽  
Daniele De Marchi ◽  
Vincenzo Positano ◽  
Gaetano Giuffrida ◽  
Sabrina Armari ◽  
...  
Keyword(s):  
Iron Overload ◽  
Conflicts Of Interest ◽  
Left Kidney ◽  
Significant Negative Correlation ◽  
Thalassemia Major ◽  
Iron Deposition ◽  
Significant Difference ◽  
The Mean ◽  
The Right ◽  
T2 Mri

Abstract Abstract 5177 Background. Renal dysfunction has been reported in adult subjects with thalassemia major (TM) since 1975. One of the main cause is the iron overload consequent to regular transfusions. Multiecho T2* MRI is a well-established technique for cardiac and hepatic iron overload assessment, but there very few report concerning the kidneys. The aims of this study were to describe the T2* values of the kidneys in patients with TM, to investigate the correlation between renal and myocardial or hepatic siderosis and biventricular cardiac function. Methods. 119 TM patients (58 men, 30. 7 ± 8. 2 years) enrolled in the Myocardial Iron Overload (MIOT) networks underwent MRI. For the measurement of iron overload, multiecho T2* sequences were used. The left ventricle was segmented into a 16-segments standardized model and the T2* value on each segment was calculated as well as the global value. In the liver, the T2* value was assessed in a single region of interest (ROI) in a homogeneous area of the parenchyma. For each kidney, T2* values were calculated in three different ROIs and were averaged to obtain a representative value for the kidney. The mean T2* value over the kidneys was also calculated. Cine images were obtained to quantify biventricular morphological and functional parameters in a standard way. Results. T2* values in the right kidney were significant lower than in the left kidney (40. 3±11. 9 ms vs 44. 1±12. 7 ms, P<0. 0001). The mean T2* value over the kidneys was 42. 2±11. 9 ms and 40 patients (33. 6%) had a pathological value (T2*<36 ms, lower limit of normal evaluated on 20 healthy subjects). The mean T2* value did not show a significant difference amongst men ad women (43. 2±11. 7 ms versus 41. 3±12. 1 ms, P=0. 378). The mean T2* values increased with age in a significant manner (r=0. 321, P<0. 0001). There was a significant negative correlation between serum ferritin levels and mean renal T2* values (r=-0. 446, P<0. 0001). Significant positive correlations of the mean T2* values were demonstrated for liver (r=0. 511, P<0. 0001) and global heart (r=0. 262, P=0. 004) T2* values (Figure 1). No correlation was found between renal iron overload and bi-ventricular function parameters. Conclusions. Systemic T2* differences between left and right kidneys were found, with significant lower values in the right one. Mean T2* value increased with age. We confirmed that kidney iron deposition was not very common in TM, but it was correlated with iron deposition in liver and heart. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Adaptive Imaging Versus Periodic Surveillance for Intrafraction Motion Management During Prostate Cancer Radiotherapy

2019 ◽  
Vol 18 ◽  
pp. 153303381984448
Author(s):  
Xiangyu Ma ◽  
Huagang Yan ◽  
Ravinder Nath ◽  
Zhe Chen ◽  
Haiyun Li ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Additional Patient ◽  
Automatic Correction ◽  
Adaptive Imaging ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
The Mean

Objective: To evaluate the benefits of adaptive imaging with automatic correction compared to periodic surveillance strategies with either manual or automatic correction. Methods: Using Calypso trajectories from 54 patients with prostate cancer at 2 institutions, we simulated 5-field intensity-modulated radiation therapy and dual-arc volumetric-modulated arc therapy with periodic imaging at various frequencies and with continuous adaptive imaging, respectively. With manual/automatic correction, we assumed there was a 30/1 second delay after imaging to determine and apply couch shift. For adaptive imaging, real-time “dose-free” cine-MV images during beam delivery are used in conjunction with online-updated motion pattern information to estimate 3D displacement. Simultaneous MV-kV imaging is only used to confirm the estimated overthreshold motion and calculate couch shift, hence very low additional patient dose from kV imaging. Results: Without intrafraction intervention, the prostates could on average have moved out of a 3-mm margin for ∼20% of the beam-on time after setup imaging in current clinical situation. If the time interval from the setup imaging to beam-on can be reduced to only 30 seconds, the mean over-3 mm percentage can be reduced to ∼7%. For intensity-modulated radiation therapy simulation, with manual correction, 110 and 70 seconds imaging periods both reduced the mean over-3 mm time to ∼4%. Automatic correction could give another 1% to 2% improvement. However, with either manual or automatic correction, the maximum patient-specific over-3 mm time was still relatively high (from 6.4% to 12.6%) and those patients are actually clinically most important. In contrast, adaptive imaging with automatic intervention significantly reduced the mean percentage to 0.6% and the maximum to 2.7% and averagely only ∼1 kV image and ∼1 couch shift were needed per fraction. The results of volumetric-modulated arc therapy simulation show a similar trend to that of intensity-modulated radiation therapy. Conclusions: Adaptive continuous monitoring with automatic motion compensation is more beneficial than periodic imaging surveillance at similar or even less imaging dose.

scholarly journals A comparative study of the dosimetric impact on IMRT planning with VMAT plans using a varying number of arcs in prostate cancer

2021 ◽  
Vol 2070 (1) ◽  
pp. 012011
Author(s):  
D Kumar ◽  
A Pradhan ◽  
L M Singh
Keyword(s):  
Prostate Cancer ◽  
Radiation Therapy ◽  
Field Intensity ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Monitor Unit ◽  
Delivery Time ◽  
Treatment Delivery ◽  
Intensity Modulated ◽  
Arc Therapy

Abstract A study has been carried out to explore the impact by varying the number of arcs and beam arrangement on dose distributions. For this volumetric modulated arc therapy and 7-field, intensity-modulated radiation therapy plans have use for prostate cancer cases. The eclipse treatment planning system version 13.6 (Varian California, USA) was used to assess dosimetry data for 20 patients. All patients received intensity-modulated radiation therapy and volumetric modulated arc therapy plans with a varying number of arcs. 6MV X-Ray photon beam energy uses for each patient. Statistical plan assessments have been carried out for various dosimetric parameters to evaluate execution efficiency. There were no statistically significant changes (p>0.05) observed in D98% dose coverage while D2%, conformity index, homogeneity index, monitor unit, and treatment delivery time were showing statistically significant changes (p<0.05). In contrast to six arc volumetric modulated arc therapy and 7 field-intensity-modulated radiation therapy plans, Single arc volumetric modulated arc therapy plans showed 23.28 % and 25.96 % less monitor unit, 97.52 % and 137.53 % less treatment delivery time. It concluded that using a higher number of arcs in volumetric modulated arc therapy plans for prostate cancer improves plan efficiency. The four arc volumetric modulated arc therapy plans appeared to provide a reasonable trade-off between enhanced treatment delivery time and high treatment plan quality.

scholarly journals Inverse planned constant dose rate volumetric modulated arc therapy (VMAT) as an efficient alternative to five-field intensity modulated radiation therapy (IMRT) for prostate

2013 ◽  
Vol 13 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Conor K. McGarry ◽  
Stephen J. McMahon ◽  
David Craft ◽  
Joe M. O'Sullivan ◽  
Kevin M. Prise ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Dose Rate ◽  
Field Intensity ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Constant Dose ◽  
Pareto Fronts ◽  
Constant Dose Rate

AbstractPurposeThe aim of this work was to determine if volumetric modulated arc therapy (VMAT) plans, created for constant dose-rate (cdrVMAT) delivery are a viable alternative to step and shoot five-field intensity modulated radiation therapy (IMRT).Materials and methodsThe cdrVMAT plans, inverse planned on a treatment planning system with no solution to account for couch top or rails, were created for delivery on a linear accelerator with no variable dose rate control system. A series of five-field IMRT and cdrVMAT plans were created using dual partial arcs (gantry rotating between 260° and 100°) with 4° control points for ten prostate patients with the average rectal constraint incrementally increased. Pareto fronts were compared for the planning target volume homogeneity and average rectal dose between the two techniques for each patient. Also investigated were tumour control probability and normal tissue complication probability values for each technique. The delivery parameters [monitor units (MU) and time] and delivery accuracy of the IMRT and VMAT plans were also compared.ResultsPareto fronts showed that the dual partial arc plans were superior to the five-field IMRT plans, particularly for the clinically acceptable plans where average rectal doses were less for rotational plans (p = 0·009) with no statistical difference in target homogeneity. The cdrVMAT plans had significantly more MU (p = 0·005) but the average delivery time was significantly less than the IMRT plans by 42%. All clinically acceptable cdrVMAT plans were accurate in their delivery (gamma 99·2 ± 1·1%, 3%3 mm criteria).ConclusionsAccurate delivery of dual partial arc cdrVMAT avoiding the couch top and rails has been demonstrated.

scholarly journals POS0586 RHEUMATOID ARTHRITIS IS AN INFLAMMATORY DISEASE WITH A HIGH CARDIOVASCULAR RISK

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 526.1-526
Author(s):  
L. Nacef ◽  
H. Riahi ◽  
Y. Mabrouk ◽  
H. Ferjani ◽  
K. Maatallah ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Risk Factors ◽  
Cardiovascular Risk ◽  
Carotid Artery ◽  
Internal Carotid ◽  
Subclinical Atherosclerosis ◽  
External Carotid ◽  
Significant Difference ◽  
The Mean ◽  
The Right

Background:Hypertension, diabetes, and dyslipidemia are traditional risk factors of cardiac events. Carotid ultrasonography is an available way to detect subclinical atherosclerosis.Objectives:This study aimed to compare the intima-media thickness in RA patients based on their personal cardiovascular (CV) history of hypertension (hypertension), diabetes, and dyslipidemia.Methods:The present study is a prospective study conducted on Tunisian RA patients in the rheumatology department of Mohamed Kassab University Hospital (March and December 2020). The characteristics of the patients and those of the disease were collected.The high-resolution B-mode carotid US measured the IMT, according to American Society of Echocardiography guidelines. The carotid bulb below its bifurcation and the internal and external carotid arteries were evaluated bilaterally with grayscale, spectral, and color Doppler ultrasonography using proprietary software for carotid artery measurements. IMT was measured using the two inner layers of the common carotid artery, and an increased IMT was defined as ≥0.9 mm. A Framingham score was calculated to predict the cardiovascular risk at 10-year.Results:Forty-seven patients were collected, 78.7% of whom were women. The mean age was 52.5 ±11.06 [32-76]. The rheumatoid factor (RF) was positive in 57.8% of cases, and anti-citrullinated peptide antibodies (ACPA) were positive in 62.2% of cases. RA was erosive in 81.6% of cases. Hypertension (hypertension) was present in 14.9% of patients, diabetes in 12.8% of patients, and dyslipidemia in 12.8% of patients. Nine patients were active smokers. The mean IMT in the left common carotid (LCC) was 0.069 ±0.015, in the left internal carotid (LIC) was 0.069 ±0.015, in the left external carotid (LEC) was 0.060 ±0.023. The mean IMT was 0.068 ±0.01 in the right common carotid (RCC), 0.062 ±0.02 in the right internal carotid (RIC), and 0.060 ±0.016 in the right external carotid (REC). The IMT was significantly higher in the left common carotid (LCC) in patients with hypertension (p=0.025). There was no significant difference in the other ultrasound sites (LIC, LEC, RCC, RIC, and REC) according to the presence or absence of hypertension. The IMT was also significantly increased in patients with diabetes at LCC (p=0.017) and RIC (p=0.025). There was no significant difference in the IMT at different ultrasound sites between patients with and without dyslipidemia.Conclusion:Hypertension was significantly associated with the increase in IMT at the LCC level in RA patients. Diabetes had an impact on IMT in LCC and RIC. However, dyslipidemia did not affect the IMT at the different ultrasound sites.References:[1]S. Gunter and al. Arterial wave reflection and subclinical atherosclerosis in rheumatoid arthritis. Clinical and Experimental Rheumatology 2018; 36: Clinical E.xperimental.[2]Aslan and al. Assessment of local carotid stiffness in seronegative and seropositive rheumatoid arthritis. SCANDINAVIAN CARDIOVASCULAR JOURNAL, 2017.[3]Martin I. Wah-Suarez and al, Carotid ultrasound findings in rheumatoid arthritis and control subjects: A case-control study. Int J Rheum Dis. 2018;1–7.[4]Gobbic C and al. Marcadores subclínicos de aterosclerosis y factores de riesgo cardiovascular en artritis temprana. Subclinical markers of atherosclerosis and cardiovascular risk factors in early arthritis marcadores subclínicos de aterosclerose e fatores de risco cardiovascular na artrite precoce.Disclosure of Interests:None declared

scholarly journals Volumetric Modulated Arc Radiotherapy for Early Stage Non-Small-Cell Lung Carcinoma: Is It Better Than the Conventional Static Beam Intensity Modulated Radiotherapy?

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Vincent Wing Cheung Wu ◽  
Man In Pun ◽  
Cho Pan Lam ◽  
To Wing Mok ◽  
Wah Wai Mok
Keyword(s):  
Early Stage ◽  
Small Cell Lung Carcinoma ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Small Cell ◽  
Small Cell Lung ◽  
Cell Lung Carcinoma ◽  
Intensity Modulated ◽  
Significant Difference ◽  
Arc Therapy

This study compared the performance of volumetric modulated arc therapy (VMAT) techniques: single arc volumetric modulated arc therapy (SA-VMAT) and double arc volumetric modulated arc therapy (DA-VMAT) with the static beam conventional intensity modulated radiotherapy (C-IMRT) for non-small-cell lung carcinoma (NSCLC). Twelve stage I and II NSCLC patients were recruited and their planning CT with contoured planning target volume (PTV) and organs at risk (OARs) was used for planning. Using the same dose constraints and planning objectives, the C-IMRT, SA-VMAT, and DA-VMAT plans were optimized. C-IMRT consisted of 7 static beams, while SA-VMAT and DA-VMAT plans consisted of one and two full gantry rotations, respectively. No significant difference was found among the three techniques in target homogeneity and conformity. Mean lung dose in C-IMRT plan was significantly lower than that in DA-VMAT plan P=0.04. The ability of OAR sparing was similar among the three techniques, with no significant difference in V20, V10, or V5 of normal lungs, spinal cord, and heart. Less MUs were required in SA-VMAT and DA-VMAT. Besides, SA-VMAT required the shortest beam on time among the three techniques. In treatment of early stage NSCLC, no significant dosimetric superiority was shown by the VMAT techniques over C-IMRT and DA-VMAT over SA-VMAT.

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