Functional image-based radiotherapy planning for non-small cell lung cancer: A simulation study.
OBJECTIVE
To investigate the incorporation of data from single-photon emission computed tomography (SPECT) or hyperpolarized helium-3 magnetic resonance imaging ((3)He-MRI) into intensity-modulated radiotherapy (IMRT) planning for non-small cell lung cancer (NSCLC).


METHODS
Seven scenarios were simulated that represent cases of NSCLC with significant functional lung defects. Two independent IMRT plans were produced for each scenario; one to minimise total lung volume receiving >or=20Gy (V(20)), and the other to minimise only the functional lung volume receiving >or=20Gy (FV(20)). Dose-volume characteristics and a plan quality index related to planning target volume coverage by the 95% isodose (V(PTV95)/FV(20)) were compared between anatomical and functional plans using the Wilcoxon signed ranks test.


RESULTS
Compared to anatomical IMRT plans, functional planning reduced FV(20) (median 2.7%, range 0.6-3.5%, p=0.02), and total lung V(20) (median 1.5%, 0.5-2.7%, p=0.02), with a small reduction in mean functional lung dose (median 0.4Gy, 0-0.7Gy, p=0.03). There were no significant differences in target volume coverage or organ-at-risk doses. Plan quality index was improved for functional plans (median increase 1.4, range 0-11.8, p=0.02).


CONCLUSIONS
Statistically significant reductions in FV(20), V(20) and mean functional lung dose are possible when IMRT planning is supplemented by functional information derived from SPECT or (3)He-MRI.
Bates
Emma L
EL
Department of Clinical Oncology, Weston Park Hospital, UK. emma.bates@sth.nhs.uk
Bragg
Christopher M
CM
Wild
Jim M
JM
Hatton
Matthew Q F
MQ
Ireland
Rob H
RH
D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*