Whole body iodine-131 scan is a well-established imaging method for the detection of metastatic or residual tumor sites in patients with well-differentiated thyroid cancer. Many false-positive iodine-131 scan findings mimicking metastatic thyroid cancer have long been reported. The authors describe a false positive uptake in normal gallbladder on post-ablative iodine-131 scan in a patient with papillary thyroid cancer. This finding should be considered to be another possible false-positive finding on iodine-131 whole body scan.
Carcinoma, Papillary/*pathology ; False Positive Reactions ; Female ; Gallbladder/*metabolism/ultrasonography ; Humans ; Iodine Radioisotopes/diagnostic use/pharmacokinetics/therapeutic use ; Middle Aged ; Thyroid Neoplasms/*pathology ; Whole-Body Counting

The early detection of recurrent differentiated thyroid carcinoma (DTC) cells in the post surgery DTC patients relies on the sensitivity of measuring both the level of thyroglobulin (Tg) and 131-Iodine distribution by Whole Body Scan (WBS). Undetectable level of Tg associated with negative WBS or elevated levels of Tg associated with positive WBS ("concordant") is ordinarily indicative of either absence or presence of disease. At times, elevated level of Tg with negative WBS or low levels of Tg with positive WBS ("discordant") could also occur. In the present study, we retrospectively reviewed series of 573 patients with DTC followed in the Diagnostic Imaging and Radiotherapy of the University "Federico II" of Naples between 1993 and 1997. We focused on 9 out of 573 patients (1.56%) who had a discordant pattern with low level of Tg/positive WBS in the post-surgical follow-up. Four patients were metastatic at presentation while 5 patients with metastasis during follow-up still remained in persistently low levels of Tg (<5 ng/mL). This result does point to some flaw in the evaluation of "discordant" cases. Reviewing data previously described series by resetting cut-off values of Tg <1 ng/ml as undetectable changed the apparent "discordant" subgroup of patients into "concordant". Recent introduction of recombinant human TSH (rhTSH) to enhance the expression level of Tg brought significant increase in the sensitivity of diagnostic evaluation of thyroid cancer patients. The role of burdensome WBS in the follow up evaluation of DTC patients is significantly reduced over time especially in low-risk patients while the relevance of Tg assay is steadily increased. Sensitive Tg assays, significantly improved our ability to assess disease status in follow-up of DTC. Given the possibility of late disease relapses, the need for long-term follow-up, and reduced delay in treatment of persistent disease, there is still need for greater sensitive diagnostic tools for DTC.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biological Markers/blood ; Biomedical Technology ; Carcinoma/*diagnosis/drug therapy/radionuclide imaging ; Female ; Follow-Up Studies ; Humans ; Iodine Radioisotopes/diagnostic use ; Male ; Middle Aged ; Recombinant Proteins/diagnostic use ; Research Support, Non-U.S. Gov't ; Thyroglobulin/*blood ; Thyroid Neoplasms/*diagnosis/drug therapy/radionuclide imaging ; Thyrotropin/*diagnostic use ; Whole-Body Counting

PURPOSE: Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidyl choline to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. MATERIAL AND METHODS: The reaction mixture for the PLD assay contained 0.1microCi 1,2-di[1-14C]palmitoyl phosphatidylcholine, 0.5mM phosphatidylcholine, 5mM sodium oleate, 0.2% taurodeoxycholate, 50mM HEPES buffer (pH 6.5), 10mM CaCl2, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cm x 10cm and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy. RESULTS: Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward gamma-ray with more than two times amplification in their activities. In contrast, the PLD activity of bone marrow appears to be reduced to nearly 30%. Irradiation effect was hardly detected in liver which showed the lowest PLD activity. CONCLUSION: The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation strongly indicates that the PLD is closely related to the physiological function of these organs. Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell proliferation to cell death on these organs.
Animals ; Attention ; Bone Marrow ; Brain ; Cell Death ; Cell Proliferation ; Choline ; Cobalt ; Female ; Hematopoiesis ; HEPES ; Humans ; Hydrolysis ; Kidney ; Liver ; Lung ; Muscle, Skeletal ; Oleic Acid ; Phosphatidic Acids ; Phosphatidylcholines ; Phospholipase D* ; Phospholipases* ; Radiation Effects ; Radioactivity ; Rats* ; Rats, Wistar ; Scintillation Counting ; Signal Transduction ; Sodium ; Spleen ; Taurodeoxycholic Acid ; Thymus Gland ; Whole-Body Irradiation