carbon-11-methionine and Head-and-Neck-Neoplasms

Previously, we showed that the net metabolic clearance of 11C-methionine of the parotid gland, K, calculated from dynamic 11C-methionine PET, can be used as a measure of parotid gland function. The aim of this study was to investigate by dynamic 11C-methionine PET the individual radiation dose response relationship of parotid glands in head and neck cancer patients.. Twelve head and neck cancer patients were examined by dynamic 11C-methionine PET after radiotherapy. Parametric images of K were generated, co-registered and compared voxel-by-voxel with the 3D radiation dose plan within the parotid gland to assess the individual radiation dose-function relationship.. In each patient, voxel-values of K decreased with increasing radiation dose. Population based analysis showed a sigmoid dose response relationship of parotid gland, from which we estimated a threshold radiation dose of 16 Gy and a mean TD50 of 30 Gy. TD50 ranged from 7 to 50 Gy in the group of patients.. Individual radiation dose response of parotid glands can be measured by dynamic 11C-methionine PET. The dose response analysis revealed a sigmoid relationship, a threshold radiation dose of 16 Gy, and a mean TD50 of 30 Gy.

Topics: Aged; Female; Head and Neck Neoplasms; Humans; Image Interpretation, Computer-Assisted; Male; Methionine; Middle Aged; Parotid Gland; Positron-Emission Tomography; Radiation Dosage; Radiometry; Radiopharmaceuticals; Relative Biological Effectiveness; Reproducibility of Results; Sensitivity and Specificity

To evaluate whether positron emission tomography (PET) with carbon-11-methionine (MET) can be used for detection of early response to external beam radiotherapy (RT) in untreated head and neck cancer using locoregional control and survival as study endpoints.. Fifteen patients with head and neck cancer underwent a MET PET study before RT and after a median dose of 24 Gy. Fractionation was standard (n = 6) or hyperfractionated (n = 9), and 13 out of 15 patients had planned surgery after RT. SUV was calculated for primary tumor (n = 13) or largest lymph node metastasis in two patients of whom one had his primary excised before study enrollment and one presented with unknown primary tumor syndrome.. Attenuation corrected PET scans acquired 20-40 min from tracer injection were used for evaluation of MET uptake in tumors. A quantitative MET uptake index was expressed as standardized uptake value (SUV) or SUV(lean) (corrected for lean body mass). The PET results were correlated with clinical follow-up data. The median follow-up time is currently 28 months (range 22-34).. A total of 13 primary tumors and 12 metastatic lymph nodes were visually identified in MET PET. In the first PET study the median SUV in tumor was 8.6 (range, 5.5-14.0). In the second PET study performed during RT the median SUV decreased to 5.7 (range, 3.1-8.2, P = 0.001). Two out of 15 patients showed no radiation-induced decrease in SUV. The median tumor SUV ratio of patients remaining in local control (CR) after RT was 0.7 (range 0.6-0.8, n = 6), and that of relapsing patients similarly 0.7 (range 0.5-1.0, n = 9, NS). The SUV ratio was not associated with survival time. The MET uptake of submandibular salivary glands decreased in all patients during the first two or three weeks of RT (P = 0.03).. MET uptake in tumor shows a significant decrease during the first two to three weeks of RT of head and neck cancer. It appears that the rate of decrease in tracer uptake is comparable in relapsing patients and those who remain locally controlled and thus the use of MET PET for prediction of response to RT is limited.

Topics: Aged; Carbon Radioisotopes; Dose Fractionation, Radiation; Evaluation Studies as Topic; Female; Follow-Up Studies; Forecasting; Head and Neck Neoplasms; Humans; Lymphatic Metastasis; Male; Methionine; Middle Aged; Neoplasm Recurrence, Local; Neoplasms, Unknown Primary; Radiopharmaceuticals; Radiotherapy Dosage; Remission Induction; Submandibular Gland; Survival Rate; Tomography, Emission-Computed

The purpose of this study was to investigate whether uptake of L-methyl-[11C]-methionine in a tumor is related to the survival of patients with squamous cell cancer of the head and neck.. Thirty-nine patients (median age 64 yr) with newly diagnosed squamous cell carcinoma of the head and neck entered a PET study with [11C]-methionine before therapy. Tumor [11C]-methionine uptake was measured as standardized uptake values (SUVs), and the PET results were compared with the clinical follow-up data of the patients.. All except one of the malignant lesions within the field of view were visible by [11C]-methionine PET. The median tumor SUV was 9.0 (range 4.0-18.8). The median follow-up time for patients still alive is currently 44 mo (range 14-66 mo). No difference in survival was found between patients with tumor SUV equal to or larger than the median and those with tumor SUV smaller than the median.. Carbon-11-methionine PET imaging is effective in squamous cell head and neck cancer. The amount of [11C]-methionine uptake does not predict the clinical outcome.

Topics: Carbon Radioisotopes; Carcinoma, Squamous Cell; Female; Follow-Up Studies; Head and Neck Neoplasms; Humans; Male; Methionine; Middle Aged; Radiopharmaceuticals; Survival Rate; Time Factors; Tomography, Emission-Computed