A novel conformity index for intensity modulated radiation therapy plan evaluation

2012 ◽  
Vol 39 (9) ◽  
pp. 5740-5756 ◽  
Author(s):  
Fion W. K. Cheung ◽  
Maria Y. Y. Law
Keyword(s):  
Radiation Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Conformity Index ◽  
Plan Evaluation ◽  
Intensity Modulated

Dosimetric comparison of helical tomotherapy, volume-modulated arc therapy, and fixed-field intensity-modulated radiation therapy in nasopharyngeal and cervical cancers

2020 ◽  
Author(s):  
Deyang Yu ◽  
Shan Lu ◽  
Lei Wang ◽  
Xueyuan Hu ◽  
Xin Li ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Field Intensity ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Conformity Index ◽  
High Dose ◽  
Fixed Field ◽  
Intensity Modulated ◽  
Radiation Delivery ◽  
Arc Therapy

Abstract Background: To compare the dosimetric parameters of different radiotherapy plans, helical tomotherapy(HT), volume-modulated arc therapy (VMAT), and fixed-field intensity-modulated radiation therapy (FF-IMRT) for nasopharyngeal carcinoma (NPC) and cervical cancer (CC).Methods: A total of 15 patients with NPC and 15 patients with CC were chosen for retrospective analysis and replanned for HT, VMAT, and FF-IMRT. The prescribed doses of the planning target were 2.12/69.96 Gy, 1.8/59.4 Gy for NPC and 1.8/45 Gy for CC, respectively. The dosimetric parameters of the planning target, organs at risk (OARs), and the efficiency of radiation delivery were assessed and compared using the paired-samples t-test.Results: Compared with VMAT and FF-IMRT, HT plans significantly improved the mean conformity index (CI) and homogeneity index (HI). For the OARs, the HT plans reduced the maximum doses of most organs, such as brainstem, spinal cord, and optic nerves in NPC, and significantly reduced the volume of the high-dose region in NPC and the V30 and V40 of small bowel, rectum, and bladder in CC. However, VMAT evidently reduced the treatment time and improved the efficiency of radiation delivery than HT.Conclusions: For NPC and CC, results showed that HT and VMAT possessed better homogeneity and conformity of the target and better sparing of OARs compared with the conventional FF-IMRT, and HT achieved the best effect. VMAT had the shortest radiation delivery time. The results of this study can provide guidance for the selection of appropriate radiation technologies for patients with NPC and CC who are undergoing concurrent chemoradiotherapy.

scholarly journals Comparison of dosimetry in head and neck cancer patients treated with intensity modulated radiation therapy and helical tomotherapy

2021 ◽  
Vol 9 (11) ◽  
pp. 3374
Author(s):  
Yashaswini B. R. ◽  
Kumara Swamy
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Radiation Therapy ◽  
Head And Neck ◽  
Helical Tomotherapy ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Conformity Index ◽  
Homogeneity Index ◽  
Intensity Modulated

Background: This study was conducted to compare dosimetric parameters and dose to specific organs at risk (spinal cord and parotids) between intensity modulated radiation therapy (IMRT) and helical tomotherapy (HT) in head and neck squamous cell carcinomas (HNSCC).Methods: Thirty patients with histologically proven HNSCC were treated with chemo radiotherapy, to a dose of 60-70 Gray in 30-35 fractions. This study consists of two arms; IMRT arm and tomotherapy arm. Fifteen consecutive patients treated under IMRT and 15 patients were treated under helical tomotherapy, along with concurrent chemotherapy. PTV1 encompasses low risk planning target volume (PTV) which receives 50 Gy; PTV2 encompasses intermediate risk PTV which receives 54-60 Gy and PTV3 encompasses high risk PTV which receives 66-70 Gy. After completion of planning, dose to the organs at risk (OARs) and targets, homogeneity index and conformity index were evaluated, and tabulated.Results: On evaluation of plans we found that V95% in PTV1, PTV2 and PTV3 were 91.82%, 96.85% and 90.67% respectively for IMRT and 99.25%, 99.68% and 99.73% respectively for tomotherapy. For PTV3, V110% was 0.11% for IMRT and 0.01% for tomotherapy. Homogeneity index in IMRT arm was 0.285 and it was 0.206 in tomotherapy arm. Conformity index was found to be 1.04 for IMRT plans and 1.06 for tomotherapy plans. When mean dose to contra lateral parotids was evaluated, it was 26.91 Gy in IMRT arm and 25.97 Gy in tomotherapy arm. Max dose to spinal cord was better in tomotherapy (43.07 Gy in IMRT and 34.41 Gy in tomotherapy).Conclusions: There was statistically significant reduction in spinal cord maximum dose and point doses in tomotherapy plans compared to IMRT plans. The decrease in spinal cord dose can increase the tolerance reserve which can be useful in dose escalation or re-irradiation if required. There was also decrease in contra lateral parotid doses (not statistically significant). There was significant improvement in V95% in tomotherapy arm compared to IMRT arm, indicating the significantly superior coverage of target volumes in helical tomotherapy plans compared to IMRT plans. V110% (hot spots) inside the target was very minimal in tomotherapy arm compared to IMRT arm. Conformity index, homogeneity index between two arms were comparable.

Extra-target doses in children receiving multileaf collimator (MLC) based intensity modulated radiation therapy (IMRT)

2004 ◽  
Vol 42 (7) ◽  
pp. 626-630 ◽  
Author(s):  
Mary Koshy ◽  
Arnold C. Paulino ◽  
Robert B. Marcus ◽  
Joseph Y. Ting ◽  
Daisy Whitaker ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Multileaf Collimator ◽  
Intensity Modulated

scholarly journals Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1549
Author(s):  
Han Gyul Yoon ◽  
Yong Chan Ahn ◽  
Dongryul Oh ◽  
Jae Myoung Noh ◽  
Seung Gyu Park ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Combination Group ◽  
Intensity Modulated Proton Therapy ◽  
Oropharynx Cancer ◽  
Intensity Modulated ◽  
Before And After ◽  
Grade 3 ◽  
Early Clinical Outcomes

Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and intensity-modulated proton therapy (IMPT) in comparison with IMRT alone in treating oropharynx cancer (OPC) patients. Materials and Methods: The medical records of 148 OPC patients who underwent definitive radiotherapy (RT) with concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During the 5.5 weeks’ RT course, the initial 16 (or 18) fractions were delivered by IMRT in all patients, and the subsequent 12 (or 10) fractions were either by IMRT in 81 patients (IMRT only) or by IMPT in 67 (IMRT/IMPT combination), respectively, based on comparison of adaptive re-plan profiles and availability of equipment. Propensity-score matching (PSM) was done on 76 patients (38 from each group) for comparative analyses. Results: With the median follow-up of 24.7 months, there was no significant difference in overall survival and progression free survival between groups, both before and after PSM. Before PSM, the IMRT/IMPT combination group experienced grade ≥ 3 acute toxicities less frequently: mucositis in 37.0% and 13.4% (p < 0.001); and analgesic quantification algorithm (AQA) in 37.0% and 19.4% (p = 0.019), respectively. The same trends were observed after PSM: mucositis in 39.5% and 15.8% (p = 0.021); and AQA in 47.4% and 21.1% (p = 0.016), respectively. In multivariate logistic regression, grade ≥ 3 mucositis was significantly less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.027 and 0.024, respectively). AQA score ≥ 3 was also less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.085 and 0.018, respectively). Conclusions: In treating the OPC patients, with comparable early oncologic outcomes, more favorable acute toxicity profiles were achieved following IMRT/IMPT combination than IMRT alone.

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