Dosimetric comparison between intensity-modulated radiotherapy and volumetric-modulated arc therapy in hippocampus sparing in brain metastasis treated by whole-brain irradiation and simultaneous integrated boost

2019 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ehab Saad ◽  
Khaled Elshahat ◽  
Hussein Metwally
Keyword(s):  
Brain Metastasis ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Simultaneous Integrated Boost ◽  
Conformity Index ◽  
Whole Brain ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Integrated Boost

AbstractBackground:While treating brain metastasis with whole-brain radiotherapy incorporating a simultaneous integrated boost (WBRT-SIB), the risk of hippocampus injury is high. The aim of this study is to compare dosimetrically between intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in sparing of hippocampus and organs at risk (OARs) and planning target volume (PTV) coverage.Methods:In total, 16 patients presenting with more than one brain metastases were previously treated and then retrospectively planned using VMAT and IMRT techniques. For each patient, a dual-arc VMAT and another IMRT (five beams) plans were created. For both techniques, 30 Gy in 10 fractions was prescribed to the whole brain (WB) minus the hippocampi and 45 Gy in 10 fractions to the tumour with 0·5 cm margin. Dose–volume histogram (DVH), conformity index (CI) and homogeneity index (HI) of PTV, hippocampus mean and maximum dose and other OARs for both techniques were calculated and compared.Results:A statistically significant advantage was found in WB-PTV CI and HI with VMAT, compared to IMRT. There were lower hippocampus mean and maximum doses in VMAT than IMRT. The maximum hippocampus dose ranged between 15·5 and 19·2 Gy and between 18·4 and 20·6 Gy in VMAT and IMRT, respectively. The mean dose of the hippocampus ranged between 11·5 and 17·7 Gy and between 13·2 and 18·3 Gy in VMAT and IMRT, respectively.Conclusion:Using WBRT-SIB technique, VMAT showed better PTV coverage with less mean and maximum doses to the hippocampus than IMRT. Clinical randomised studies are needed to confirm safety and clinical benefit of WBRT-SIB.

scholarly journals Volumetric modulated arc therapy (VMAT) is superior to intensity modulated radiotherapy (IMRT) for liver sparing in SBRT for hepatocellular carcinoma

2020 ◽  
Author(s):  
Yulia Kundel ◽  
Yasmin Korzets ◽  
Miriam Weinstock-Sabbah ◽  
Assaf Moore ◽  
Noa Gordon ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Normal Liver ◽  
Point Of View ◽  
Conformity Index ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Treatment Volume

Abstract Background: The best delivery modality of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) from a technical point of view is still a matter of debate. The purpose of this study was to compare planning parameters with volumetric modulated arc therapy (VMAT) to static intensity modulated radiotherapy (IMRT) in treatment of HCC treated with SBRT. Methods: Twenty patients (pts) with localized HCC who were treated with SBRT were re-planned using two different radiation techniques: IMRT and VMAT. Patients with Child A cirrhosis received 45-54 Gy in 3 fractions and 5 pts with Child B cirrhosis received 30 Gy in 5 fractions. Planning was optimized to minimize doses to organs at risk (OAR) without compromising coverage of the planning treatment volume (PTV). VMAT and IMRT plans were compared using the conformity index (CI), homogeneity index of the PTV and monitor units (MUs) for time of treatment delivery, and other dose volume histogram (DVH) metrics.Results: The CI of VMAT plans were superior to those of IMRT(1.11±0.05 vs 1.18±0.06 (p <0.05) The MUs were significantly lower for VMAT (423.78±50.65) than for IMRT (890±160.68) (p <0.01). Stomach max dose, normal liver V15 Gy, normal liver mean dose were also decreased with VMAT planning. This was achieved without increased :V30 Gy of duodenum and small bowel , 10 cc(Gy) of duodenum, mean dose of right kidney and cord max dose . Conclusion: PTV coverage was more conformal with VMAT planning, with lower MUs and shorter delivery time compared to IMRT in all pts. Moreover VMAT planning was more effective than IMRT planning in the sparing of normal liver and stomach.

Which simultaneous-integrated boost (SIB) intensity-modulated radiotherapy (IMRT) technique is dosimetrically superior in the treatment of breast cancer; volumetric-modulated arc therapy (VMAT) or fixed field (ff) IMRT?

2017 ◽  
Vol 16 (3) ◽  
pp. 272-279
Author(s):  
Steven B. D. Murphy ◽  
Heather Drury-Smith
Keyword(s):  
Breast Cancer ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Breath Hold ◽  
Hybrid Technique ◽  
Fixed Field ◽  
Intensity Modulated ◽  
Concomitant Boost ◽  
Arc Therapy ◽  
Integrated Boost

AbstractBackground and purposeTo determine which concomitant boost technique is dosimetrically superior in the treatment of breast cancer; volumetric-modulated arc therapy (VMAT) or fixed field intensity-modulated radiotherapy (ff-IMRT).Materials and methodsIn total, 30 breast patients were re-planned with both VMAT and fixed field concomitant boost intensity-modulated radiotherapy techniques. A hybrid technique was used delivering 80% of the dose through tangential beams and 20% through an integrated boost. A two-tailed t-test sample for means was used to compare the dosimetric differences between the techniques.ResultsMaximum dose was statistically lower for VMAT; 103·2 versus 103·7% for ff-IMRT along with statistically lower V2 Gy doses to the contralateral lung (0·7 versus 1·6%) and heart for both left- (19·0%/22·6%), and right- (5·5%/8·8%) sided patients, respectively. ff-IMRT boasted significantly lower ipsilateral lung V20, V18 and V10 Gy (7·9/8·6/13·1 versus 8·1/8·8/13·4%) than VMAT, respectively. No differences were found with minimum coverage, mean dose and V5 Gy to all organs at risk (OARs).ConclusionVMAT and ff-IMRT techniques demonstrate excellent target coverage and OAR sparing facilitated by the hybrid planning technique and deep inspiration breath hold. There is no obvious dosimetrically superior option between the two techniques. Reduced treatment times with VMAT make it more desirable to implement clinically.

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