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The role of lung perfusion imaging in predicting the direction of radiation‐induced changes in pulmonary function tests
Author(s) -
Marks Lawrence B.,
Hollis Donna,
Munley Michael,
Bentel Gunilla,
Garipagaoglu Melahat,
Fan Ming,
Poulson Jeanne,
Clough Robert,
Sibley Gregory,
Coleman R. Edward,
Jaszczak Ronald
Publication year - 2000
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/(sici)1097-0142(20000501)88:9<2135::aid-cncr20>3.0.co;2-h
Subject(s) - medicine , perfusion , dlco , nuclear medicine , lung , perfusion scanning , pulmonary function testing , spect imaging , single photon emission computed tomography , radiation therapy , lung volumes , radiology , lung cancer , diffusing capacity , lung function
BACKGROUND The aim of this study was to determine whether preradiation (pre‐RT) single photon emission computed tomography (SPECT) lung perfusion scans can be used to predict RT–induced changes in pulmonary function tests (PFTs). METHODS Ninety‐four patients irradiated for thoracic tumors had pre‐RT SPECT lung perfusion scans. The presence of SPECT hypoperfusion distal to a central mediastinal tumor was qualitatively assessed visually without knowledge of PFT changes. Patients were grouped based on whether the diffusion capacity (DLCO) ever increased post‐RT. Comparisons of patient groups were performed using 1‐tailed Fisher exact tests. Patient follow‐up was 6–56 months (mean, 30 months). To assess SPECT hypoperfusion objectively, the average dose to the computed tomography (CT)–defined lung was compared with the weighted‐average dose (based on relative perfusion) to the SPECT‐defined lung. The ratio between the CT‐ and SPECT‐defined mean lung dose provided a quantitative assessment of hypoperfusion. The mean ratio for patients with central tumor and adjacent hypoperfusion was compared with that of the others (Wilcoxon rank‐sum one‐sided test). RESULTS In patients with central tumors, 41% (9 of 22) with adjacent hypoperfusion had improvements in DLCO following radiation, versus 18% (3 of 17) of those without hypoperfusion ( P = 0.11). In patients with lung carcinoma, the corresponding ratios were 40% (8 of 20) and 10% (1 of 10), respectively ( P = 0.10). The mean ratio of CT dose to SPECT dose was 1.35 for patients with central tumors and adjacent hypoperfusion versus 1.16 for others ( P = 0.017). CONCLUSIONS The presence of SPECT hypoperfusion adjacent to a central mediastinal mass may identify patients likely to have improved PFTs following RT. Thus, SPECT imaging may be useful in models for predicting radiation‐induced changes in PFTs. Cancer 2000;88:2135–41. © 2000 American Cancer Society.