Dosimetric comparison of the helical tomotherapy, volumetric-modulated arc therapy and fixed-field intensity-modulated radiotherapy for stage IIB-IIIB non-small cell lung cancer

et al. 2020

Preprint

Background: To evaluate the dosimetric parameters among three different radiotherapy techniques in patients with postoperative cervical cancer, including the Helical Tomotherapy (HT), the Volume Modulated Arc-Therapy (VMAT), and the Fixed-Field intensity modulated radiation therapy (FF-IMRT). Methods: Fifteen cervical cancer patients treated with postoperative radiotherapy were re-planning with HT, VMAT and FF-IMRT. The prescribed target dose of the patients was 1.8/45Gy. The paired-samples t-test was used to compare the dosimetric parameters of the planning target and OARs (Organs at risk), and the efficiency of radiation delivery. Results: Compared with the VMAT and FF-IMRT, the HT plans showed significant improvement in the conformity index (CI) and the homogeneity index (HI). In addition, the HT plans also significantly reduced the volume of high-dose region of the OARS, especially in the V30, V40 of small bowel, rectum and bladder. Meantime, the advantage of VMAT is that it reduced the treatment time and improved the efficiency of radiation delivery obviously, compared with the HT (293.8 ± 12.8s Vs. 557.6 ± 51.9s, P < 0.001) and FF-IMRT (293.8 ± 12.8s Vs. 581.8 ± 26.1s, P < 0.001). Conclusion: Our result reveals that HT showed better CI and HI for the target and reduced high dose volumes to OARs compared with VMAT and FF-IMRT, but the lower dose volumes to OARs increased slightly. As for the benefit of VMAT, it demonstrated the shortest treatment time. Our results could provide guidance for selecting the appropriate radiation technologies for cervical cancer patients who undergoing postoperative adjuvant pelvic radiotherapy.

Section: Discussionsupporting

confidence: 65%

Dosimetric comparison between helical tomotherapy, volume modulated arc-therapy and Fixed-Field intensity modulated radiation therapy in postoperative adjuvant radiotherapy for cervical cancer

et al. 2020

Preprint

“…Furthermore, a more tangible dose distribution can be obtained. Similar studies on tumors in other systems have shown that HT is superior to IMRT or VMAT or 3Dconformal radiotherapy in OARs, conformity, and homogeneity [34,35].…”

mentioning

confidence: 61%

Comparison of Dosimetric Gains Provided by Intensity-Modulated Radiotherapy, Volume-Modulated Arc Therapy, and Helical Tomotherapy for High-Grade Glioma

Liu

BioMed Research International

et al. 2020

Purpose. Because of the poor prognosis for high-grade glioma (HGG) patients, it is important to increase the dose of the tumor to improve the efficacy while minimizing the dose of organs at risk (OARs). Thus, we evaluated the potential dosimetric gains of helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT) or volume-modulated arc therapy (VMAT) for high-grade glioma (HGG). Methods. A total of 42 HGG patients were retrospectively selected who had undergone helical tomotherapy; then, IMRT and VMAT plans were generated and optimized for comparison after contouring crucial neuronal structures for neurogenesis and neurocognitive function. IMRT and VMAT were optimized with the Eclipse treatment planning system (TPS) (Version 11.0.31) and HT using TomoTherapy Hi-Art Software (Version 2.0.7) (Accuray, Madison, WI, USA). All three techniques were optimized for simultaneously delivering 60 Gy to planning target volume (PTV) 1 and 50-54 Gy to PTV2. We also analyzed the homogeneity index (HI) and conformity index (CI) of PTVs and organ at risk (OAR) sparing. Results. There was no significant difference in the PTV coverage among IMRT, VMAT, or HT. As for the HI, HT plans (PTV1 HI: 0.09±0.03, PTV2 HI: 0.17±0.05) had the best homogeneity when compared to IMRT plans (PTV1 HI: 0.10±0.04, PTV2 HI: 0.18±0.04) and VMAT plans (PTV1 HI: 0.11±0.03, PTV2 HI: 0.20±0.03). The CI value of HT (PTV1 CI: 0.98±0.03, PTV2: 0.98±0.05) was closest to the optimal value. Except for the IMRT and VMAT groups, there were statistically significant differences between the other two groups of the CI values in both PTV1 and PTV2. The other comparison values were statistically significant except for the optic nerve, and VMAT had the best sparing of the optic chiasm. The mean and max doses of OARs declined significantly in HT. Conclusions. For high-grade glioma patients, HT had superior outcomes in terms of PTV coverage and OAR sparing as compared with IMRT/VMAT.

“…Growing Evidences have shown that HT can sculpt radiation doses to complex-shaped tumorous regions and avoid high-dose regions to OARs through the rapid opening and closing of leaves in a collimator rotating around the patient [22]. Therefore, HT is frequently used in various diseases [23][24][25][26], including NPC and CC [27,28], nowadays. In this study, results showed that the three IMRT techniques met the clinical demand, but HT showed an evidently sharp dose gradient with the optimal HI and CI in NPC and CC.…”

Section: Discussionmentioning

confidence: 99%

“…Compared with FF-IMRT and HT, VMAT reduced the treatment delivery time by 37.5% and 55.0%, respectively, in CC and by 41.3% and 42%, respectively, in NPC. Several studies have reported that VMAT has achieved higher dose conformity of PTV and better sparing of OARs with a shorter treatment delivery time than FF-IMRT in terms of plans of different cancers [38][39][40]. Shortened treatment time may reduce the in uence of uncertain factors, the probability of patients' movement, and patients' discomfort.…”

Section: Discussionmentioning

confidence: 99%

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

Lü

et al. 2020

Preprint

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.