Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose

Abstract Purpose To investigate the influence of inhomogeneity corrections on stereotactic treatment plans for non-small cell lung cancer and determine the dose delivered to the PTV and OARs. Materials and methods For 26 patients with stage-I NSCLC treatment plans were optimized with unit density (UD), an equivalent pathlength algorithm (EPL), and a collapsed-cone (CC) algorithm, prescribing 60 Gy to the PTV. After optimization the first two plans were recalculated with the more accurate CC algorithm. Dose parameters were compared for the three different optimized plans. Dose to the target and OARs was evaluated for the recalculated plans and compared with the planned values. Results For the CC algorithm dose constraints for the ratio of the 50% isodose volume and the PTV, and the V20 Gy are harder to fulfill. After recalculation of the UD and EPL plans large variations in the dose to the PTV were observed. For the unit density plans, the dose to the PTV varied from 42.1 to 63.4 Gy for individual patients. The EPL plans all overestimated the PTV dose (average 48.0 Gy). For the lungs, the recalculated V20 Gy was highly correlated to the planned value, and was 12% higher for the UD plans (R2 = 0.99), and 15% lower for the EPL plans (R2 = 0.96). Conclusion Inhomogeneity corrections have a large influence on the dose delivered to the PTV and OARs for SBRT of lung tumors. A simple rescaling of the dose to the PTV is not possible, implicating that accurate dose calculations are necessary for these treatment plans in order to prevent large discrepancies between planned and actually delivered doses to individual patients.</p

Recommendations for implementing stereotactic radiotherapy in peripheral stage IA non-small cell lung cancer: report from the Quality Assurance Working Party of the randomised phase III ROSEL study

<p>Abstract</p> <p>Background</p> <p>A phase III multi-centre randomised trial (ROSEL) has been initiated to establish the role of stereotactic radiotherapy in patients with operable stage IA lung cancer. Due to rapid changes in radiotherapy technology and evolving techniques for image-guided delivery, guidelines had to be developed in order to ensure uniformity in implementation of stereotactic radiotherapy in this multi-centre study.</p> <p>Methods/Design</p> <p>A Quality Assurance Working Party was formed by radiation oncologists and clinical physicists from both academic as well as non-academic hospitals that had already implemented stereotactic radiotherapy for lung cancer. A literature survey was conducted and consensus meetings were held in which both the knowledge from the literature and clinical experience were pooled. In addition, a planning study was performed in 26 stage I patients, of which 22 were stage 1A, in order to develop and evaluate the planning guidelines. Plans were optimised according to parameters adopted from RTOG trials using both an algorithm with a simple homogeneity correction (Type A) and a more advanced algorithm (Type B). Dose conformity requirements were then formulated based on these results.</p> <p>Conclusion</p> <p>Based on current literature and expert experience, guidelines were formulated for this phase III study of stereotactic radiotherapy versus surgery. These guidelines can serve to facilitate the design of future multi-centre clinical trials of stereotactic radiotherapy in other patient groups and aid a more uniform implementation of this technique outside clinical trials.</p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-7

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-4

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-1

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-10

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-5

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p

Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose-2

<p><b>Copyright information:</b></p><p>Taken from "Developing and evaluating stereotactic lung RT trials: what we should know about the influence of inhomogeneity corrections on dose"</p><p>http://www.ro-journal.com/content/3/1/21</p><p>Radiation Oncology (London, England) 2008;3():21-21.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2515326.</p><p></p