Respiration-correlated image guidance is the most important radiotherapy motion management strategy for most lung cancer patients

Stine Korreman, Gitte Bjørnsen Fredberg Persson, Ditte Eklund Nygaard, Carsten Brink, Trine Juhler-Nøttrup

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstract

Purpose
The purpose of this study was to quantify the effects of four-dimensional computed tomography (4DCT), 4D imageguidance (4D-IG), and beam gating on calculated treatment field margins in a lungcancerpatient population.

Materials and Methods
Images were acquired from 46 lungcancerpatients participating in four separate protocols at three institutions in Europe and the United States. Seven patients were imaged using fluoroscopy, and 39 patients were imaged using 4DCT.

The magnitude of respiratory tumor motion was measured. The required treatment field margins were calculated using a statistical recipe (van Herk M, et al. Int J Radiat Oncol Biol Phys 2000;474:1121–1135), with magnitudes of all uncertainties, except respiratory peak-to-peak displacement, the same for all patients, taken from literature. Required margins for respiratory motionmanagement were calculated using the residual respiratory tumor motion for each patient for various motionmanagementstrategies. Margin reductions for respirationmanagement were calculated using 4DCT, 4D-IG, and gated beam delivery.

Results
The median tumor motion magnitude was 4.4 mm for the 46 patients (range 0–29.3 mm). This value corresponded to required treatment field margins of 13.7 to 36.3 mm (median 14.4 mm). The use of 4DCT, 4D-IG, and beam gating required margins that were reduced by 0 to 13.9 mm (median 0.5 mm), 3 to 5.2 mm (median 5.1 mm), and 0 to 7 mm (median 0.2 mm), respectively, to a total of 8.5 to 12.4 mm (median 8.6 mm).

Conclusion
A respiratory managementstrategy for lungcancerradiotherapy including planning on 4DCT scans and daily imageguidance provides a potential reduction of 37% to 47% in treatment field margins. The 4D imageguidancestrategy was the most effective strategy for >85% of the patients.
OriginalsprogEngelsk
TidsskriftInternational Journal of Radiation Oncology, Biology, Physics
Vol/bind83
Udgave nummer4
Sider (fra-til)1338-1343
ISSN0360-3016
DOI
StatusUdgivet - 13 jan. 2012

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