Waldeland E, Ramberg C, Arnesen MR, Helland A, Brustugun OT, Malinen E. Dosimetric impact of a frame-based strategy in stereotactic radiotherapy of lung tumors.
Acta Oncol 2012;
51:603-9. [PMID:
22304490 DOI:
10.3109/0284186x.2012.658115]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION
Technological innovations have taken stereotactic body radiotherapy (SBRT) from frame-based strategies to image-guided strategies. In this study, cone beam computed tomography (CBCT) images acquired prior to SBRT of patients with lung tumors was used to study the dosimetric impact of a pure frame-based strategy.
MATERIAL AND METHODS
Thirty patients with inoperable lung tumors were retrospectively analyzed. All patients had received CBCT-guided SBRT with 3 fractions of 15 Gy to the planning target volume (PTV) margin including immobilization in a stereotactic body frame (SBF). Using the set-up corrections from the co-registration of the CBCT with the planning CT, all individual dose plans were recalculated with an isocenter position equal to the initial set-up position. Dose Volume Histogram (DVH) parameters of the recalculated dose plans were then analyzed.
RESULTS
The simulated plans showed that 88% of all fractions resulted in minimum 14.5 Gy to the internal target volume (ITV). For the simulated summed treatment (3 fractions per patient), 83% of the patients would minimum receive the prescription dose (45 Gy) to 100% of the ITV and all except one would receive the prescription dose to more than 90% of the ITV.
CONCLUSIONS
SBRT including SBF, but without image guidance, results in appropriate dose coverage in most cases, using the current margins. With image guidance, margins for SBRT of lung tumors could possibly be reduced.
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