RT Journal Article SR Electronic T1 Prognostic Impact of Hypoxia Imaging with 18F-Misonidazole PET in Non-Small Cell Lung Cancer and Head and Neck Cancer Before Radiotherapy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 253 OP 260 VO 46 IS 2 A1 Susanne-Martina Eschmann A1 Frank Paulsen A1 Matthias Reimold A1 Helmut Dittmann A1 Stefan Welz A1 Gerald Reischl A1 Hans-Juergen Machulla A1 Roland Bares YR 2005 UL http://jnm.snmjournals.org/content/46/2/253.abstract AB In radiotherapy of head and neck cancer (HNC) and non-small cell lung cancer (NSCLC), hypoxia is known to be an important prognostic factor for long-term survival and local tumor control. The PET tracer 18F-fluoromisonidazole (FMISO) allows noninvasive assessment of tumor hypoxia. This study analyzed whether FMISO PET could predict tumor recurrence after radiotherapy. Methods: Forty patients with advanced HNC (n = 26) or NSCLC (n = 14) were studied before curative radiotherapy. Dynamic (0–15 min) and static PET scans were acquired up to 4 h after injection of 400 MBq of FMISO. Standardized uptake values (SUVs) and ratios to reference tissues (mediastinum or muscle) were calculated. In addition, time–activity curves up to 14 min after injection were classified visually. PET data were correlated with clinical follow-up data (presence or absence of local recurrence within 1 y), which were available for 21 patients. Results: For HNC, patients with local recurrence could be separated from disease-free patients by SUV 4 h after injection (all recurrences had an SUV > 2). For NSCLC, no such correlation was observed. The tumor-to-muscle ratios (T/Mu) and tumor-to-mediastinum ratios (T/Me) at 4 h after injection correlated with the risk of relapse in both tumor entities: All patients with a T/Me greater than 2.0 (NSCLC, n = 5) or with a T/Mu greater than 1.6 (HNC, n = 5) presented with tumor recurrence, whereas only 3 of the remaining 11 patients experienced recurrence (27%). Qualitative analysis of time–activity curves for 37 patients revealed 3 curve types (rapid washout, n = 9; intermediate [delayed washout], n = 12; and accumulation, n = 16). Eighteen patients categorized by curve type could be followed up: In 5 of 6 patients with an accumulation curve, disease recurred locally within 1 y, compared with 5 of 8 patients with a delayed-washout curve and 0 of 4 with a rapid-washout curve. Conclusion: Our results indicate that outcome after radiotherapy can be predicted on the basis of kinetic behavior of FMISO in tumor tissue. An accumulation-type curve, high SUV, and high T/Mu and T/Me at 4 h after injection are highly suggestive of an incomplete response to treatment and might be used to select patients for intensified therapy protocols.