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SU‐F‐J‐222: Using PET Imaging to Evaluate Proliferation and Blood Flow in Irradiated and Non‐Irradiated Bone Marrow 1 Year After Chemoradiation Therapy
Author(s) -
McGuire S,
Ponto L,
Menda Y
Publication year - 2016
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4956130
Subject(s) - medicine , nuclear medicine , bone marrow , radiation therapy , blood flow , standardized uptake value , radiology , positron emission tomography
Purpose: To compare proliferation and blood flow in pelvic and thoracic bone marrow 1 year after pelvic chemoradiation. Methods: Sixteen pelvic cancer patients were enrolled in an IRB‐approved protocol to acquire FLT PET images during radiation therapy simulation (baseline) and 1 year after chemoradiation therapy. Three subjects also had optional O‐15 water PET images acquired 1 year after chemoradiation therapy. Baseline FLT PET images were used to create IMRT plans to spare pelvic bone marrow identified as regions with FLT SUV ≥ 2 without compromising PTV coverage or OAR sparing. Marrow VOIs were defined using a 50% maximum pixel value threshold on baseline FLT PET images (VIEW, PMOD version 3.5) in the sacrum and thoracic spine representing irradiated and non‐irradiated regions, respectively. FLT PET and O‐15 water PET images acquired 1 year after therapy were co‐registered to baseline images (FUSION PMOD) and the same VOIs were used to measure proliferation (FLT SUV) and blood flow (O‐15 water uptake). Separate image‐based input functions were used for blood flow quantitation in each VOI. Results: Mean 1 year FLT SUV in sacral and thoracic VOIs for were 1.1 ± 0.4 and 6.5 ± 1.7, respectively for N = 16 subjects and were 1.2 ± 0.2 and 5.6 ± 1.6, respectively for N = 3 subjects who also underwent O‐15 water imaging. Blood flow measures in equivalent sacral and thoracic marrow regions (N = 3) were 21.3 ± 8.7 and 18.3 ± 4.9 mL/min/100mL respectively. Conclusion: Decreased bone marrow proliferation measured by FLT SUV does not appear to correspond to decreased blood flow as measured by O‐15 water PET imaging. Based on this small sample at a single time point, reduced blood supply does not explain reductions in bone marrow proliferative activity 1 year after chemoradiation therapy.