Lung SBRT: dosimetric and delivery comparison of RapidArc, TomoTherapy, and IMRT

Abstract

This study seeks to compare fixed‐field intensity‐modulated radiation therapy (FF IMRT), RapidArc (RA), and helical tomotherapy (HT) to discover the optimal treatment modality to deliver SBRT to the peripheral lung. Eight patients with peripheral primary lung cancer were reviewed. Plans were prescribed a dose of 48 Gy and optimized similarly with heterogeneity corrections. Plan quality was assessed using conformality index (CI100%), homogeneity index (HI), the ratio of the 50% isodose volume to PTV (R50%) to assess intermediate dose spillage, and normal tissue constraints. Delivery efficiency was evaluated using treatment time and MUs. Dosimetric accuracy was assessed using gamma index (3% dose difference, 3 mm DTA, 10% threshold), and measured with a PTW ARRAY seven29 and OCTAVIUS phantom. CI100%,HI, and R50% were lowest for HT compared to seven‐field coplanar IMRT and two‐arc coplanar RA (p<0.05). Normal tissue constraints were met for all modalities, except maximum rib dose due to close proximity to the PTV. RA reduced delivery time by 60% compared to HT, and 40% when compared to FF IMRT. RA also reduced the mean MUs by 77% when compared to HT, and by 22% compared to FF IMRT. All modalities can be delivered accurately, with mean QA pass rates over 97%. For peripheral lung SBRT treatments, HT performed better dosimetrically, reducing maximum rib dose, as well as improving dose conformity and uniformity. RA and FF IMRT plan quality was equivalent to HT for patients with minimal or no overlap of the PTV with the chest wall, but was reduced for patients with a larger overlap. RA and IMRT were equivalent, but the reduced treatment times of RA make it a more efficient modality.PACS numbers: 87.53.Ly87.55.N‐, 87.55.D‐, 87.56.bd

Comparison of Single-fraction and Multi-fraction Stereotactic Radiotherapy for Patients with 18F-fluorodeoxyglucose Positron Emission Tomography-staged Pulmonary Oligometastases

“…The use of non-coplanar angles minimises the overlap between fields, spreading the intermediate doses in the cranial-caudal direction with resultant increased intermediate-dose conformity. Our findings are similar to a previous study published by Weyh et al [22], which reported coplanar VMAT/IMRT as having inferior dosimetry to helical tomotherapy in terms of conformity.…”

Comprehensive dosimetric planning comparison for early‐stage, non‐small cell lung cancer with SABR: fixed‐beam IMRT versus VMAT versus TomoTherapy

“…Several other studies have investigated the role of different IMRT treatment techniques in the treatment of early stage NSCLC with SABR to reduce lung toxicities (27,28) . Kannarunimit et al (27) compared three SABR treatment techniques, robotic surgery, RA, and HT plan, for treatment of central lung with SABR.…”

“…Weyh et al (28) compared RA, HT, and fixed beam for SABR treatment to lesions in the peripheral lung to conclude RA and fixed beam plans were equivalent, but the reduction in treatment time with RA makes them more preferable. This study has supported their work and furthermore, our results demonstrate a decrease in all normal lung DVH parameters in RA and SA, albeit not significant.…”

Intensity-Modulated Radiotherapy for Lung Cancer: Current Status and Future Developments

“…8,10,11 Of the groups who investigated the dose to the heart, four demonstrated an advantage with IMRT 8-10,12 and two did not find any benefit. 10,14,[32][33][34][35] For example, Ong et al 13 showed an 8-minute time reduction if VMAT was used compared to IMRT. 8,10,13,14,30 Table 3 compares different IMRT planning techniques.…”

“…When spinal cord dose was examined, five out of six groups found a significant advantage with IMRT. Weyh et al 35 compared tomotherapy, IMRT, and VMAT and reported a significant treatment time benefit using VMAT (6.5 minutes) compared to the other two techniques (IMRT: 11.1 minutes, tomotherapy: 15.9 minutes). Apart from treatment time, there is no clear benefit for one technique above the others.…”