[A case of chylothorax in which thoracoscopy under local anesthesia and thoracic duct scintigraphy were useful to locate the leakage site].

BACKGROUND: Detailed investigation of the cause of chylothorax and its treatment should be performed by thoracoscopy under general anesthesia, but if this is difficult due to multiple complications it is possible to perform a detailed investigation by combining thoracoscopy under local anesthesia and thoracic duct scintigraphy. CASE PRESENTATION: A 74-year-old woman presented with exertional dyspnea. Chest X-ray films showed right pleural effusion, and thoracocentesis yielded a milky white pleural effusion, meeting the criteria of chylothorax, after excluding conditions such as malignant lymphoma, amyloidosis and trauma. Since the patient's medical history included pacemaker insertion, dialysis and diabetes, thoracoscopy was performed under local anesthesia rather than general anesthesia, to investigate the cause in detail. The pleural cavity was visualized, but no obvious tumor or other cause was present in the parietal pleura. There was partial adhesion of the lower lobe and chest wall, and the leakage of a milky white pleural effusion from this site was confirmed. We then performed thoracic duct scintigraphy, which revealed an area of enhancement corresponding to the leakage site near the right pulmonary hilum. CONCLUSION: We describe a case in which thoracoscopy under local anesthesia and thoracic duct scintigraphy were useful for determining the leakage site in chylothorax.

Preclinical and clinical evaluation of O-[11C]methyl-L-tyrosine for tumor imaging by positron emission tomography.

We performed preclinical and clinical studies of O-[11C]methyl-L-tyrosine, a potential tracer for imaging amino acid transport of tumors by positron emission tomography (PET). Examinations of the radiation-absorbed dose by O-[11C]methyl-L-tyrosine and the acute toxicity and mutagenicity of O-methyl-L-tyrosine showed suitability of the tracer for clinical use. The whole-body imaging of monkeys and healthy humans by PET showed low uptake of O-[11C]methyl-L-tyrosine in all normal organs except for the urinary track and bladder, suggesting that the O-[11C]methyl-L-tyrosine PET has the potential for tumor imaging in the whole-body. Finally, the brain tumor imaging was preliminarily demonstrated.

Evaluation of [11C]SA5845 and [11C]SA4503 for imaging of sigma receptors in tumors by animal PET.

Sigma receptors are expressed in a wide variety of tumor cell lines, and are expressed in proliferating cells. A radioligand for the visualization of sigma receptors could be useful for selective detection of primary tumors and their metastases, and for non-invasive assessment of tumor proliferative status. To this end we evaluated two sigma receptor ligands, [11C]SA5845 and [11C]SA4503. In an in vitro study, AH109A hepatoma showed moderate densities of sigma1 and sigma2 receptors, and VX-2 carcinoma showed a high density of sigma2 receptors: Bmax (fmol/mg protein) for sigma1 vs. sigma2, 1,700 vs. 1,200 for AH109A hepatoma and 800 vs. 10,000 for VX-2 carcinoma. In a cell growth assay in vitro, neither SA5845 nor SA4503 (<10 microM) showed any inhibitory effect on proliferation of the AH109A hepatoma cells. In rats, the uptake of [11C]SA5845 and [11C]SA4503 in AH109A tissues was accumulated over the first 60 minutes; however, the uptake of both tracers increased by co-injection with haloperidol as a sigma receptor ligand. On the other hand, in the PET studies of rabbits, the uptake of [11C]SA5845 in the VX-2 carcinoma was relatively higher than that of [11C]SA4503, because of a much higher density of sigma2 receptors compared to sigma1 receptors in the VX-2 tissue, and the uptake of both tracers in the VX-2 tissue was decreased by carrier-loading and pre-treatment with haloperidol ([11C]SA5845, 53% and 26%, respectively; [11C]SA4503, 41% and 22%, respectively at 30 minutes after injection). Therefore, [11C]SA5845 and [11C]SA4503 may be potential ligands for PET imaging of sigma receptor-rich tumors.