Hitoya Ohta

The design of a pentavalent 99mTc− dimercaptosuccinate complex as a tumor imaging agent

In our search for a technetium-tumor seeking agent, the chemical characteristic of polynuclear Ga-citrate attracted our attention. On this basis, we selected the ligand dimercaptosuccinic acid (DMS) and appropriate labeling conditions in the design of 99mTc(V)-DMS. Chemical characterization was performed by thin layer chromatography, electrophoresis, Sephadex column chromatography and spectrophotometric studies at the chemical concentration (99Tc). Biodistribution in mice bearing Ehrlich ascites tumor and scintigraphic images in VX-2 tumor-bearing rabbit, indicated the great applicability of 99mTc(V)-DMS as a new tumor imaging agent. Its distinctive characteristic, different from the kidney imaging agent (99mTc-DMSA) is demonstrated and the biological implication of hydrolytic polynucleation of pentavalent technetium, through an anionic specie Tc(V)O3-(4), in the tumor cell is discussed.

Serum CA 19-9 concentrations and computed tomography findings in patients with pancreatic carcinoma.

Carbohydrate antigen (CA) 19‐9 is a new tumor markerdefined by a monoclonal antibody. Serum CA 19‐9 concentrations and computed tomography (CT) findings were studied in 55 patients with histologically proven adenocarcinomaand in 22 patients with chronic pancreatitis. CA 19‐9 was useful in 83% of cases for the differential diagnosis between pancreatic carcinoma and chronic pancreatitisand serum CA 19‐9 levels in pancreatic carcinoma were highly related to the size of tumors. Serum CA 19‐9 levels greater than 37 U/ml were seen in patients with a tumor of less than 3 cm3 to 5 cmand greater than 5 cm in diameter 13% (1/8)90% (19/21)and 92% (24/26) of casesrespectively. Tumor locationhoweverwas unrelated to serum CA 19‐9 value. These results indicated that the measurement of serum CA 19‐9 concentrations would be useful in mostif not allcases for the differential diagnosis between pancreatic carcinoma and chronic pancreatitisand for the evaluation of tumor burden in patients with pancreatic carcinoma.

Imaging of Soft Tissue Tumors with Tc(v)-99m Dimercaptosuccinic Acid: A New Tumor-seeking Agent

Tumor scintigraphy, using Tc(V)-99m dimercaptosuccinic acid (Tc(V)-DMS) was performed in 58 patients with soft tissue tumors, and the results were compared with that of Ga-67 citrate. Tc(V)-DMS was found to have a sensitivity of 90% for malignant tumors including aggressive fibromatosis compared to that of Ga-67 citrate, which was 56%. However, the specificity of Tc(V)-DMS for these tumors was 71% but with Ga-67 citrate the specificity was 80%. The imaging accuracy in soft tissue tumors with Tc(V)-DMS and Ga-67 citrate was 78% and 71%, respectively. Although the accumulation of Tc(V)-DMS has been detected in some benign soft tissue tumors, the reduced accumulation in inflammatory lesions compared to Ga-67 citrate was recognized, and Tc(V)-DMS could be of great use in the detection of extension or location of malignant soft tissue tumors.

Imaging of head and neck tumors with technetium(V)-99m DMSA. A new tumor-seeking agent

Tumor scintigraphy, using Tc(V)-99m DMSA was performed on 76 patients with head and neck tumors. In 32 cases, SPECT also was performed. Tc(V)-99m DMSA was found to have a sensitivity of 75% (56 cases), a specificity of 85% (20 cases) and an accuracy of 78% on planar imaging. ECT studies showed accumulation of Tc(V)-99m DMSA in all 25 malignant cases studied. However, in benign tumors, four of seven cases (57%) showed radionuclide uptake. Tc(V)-99m DMSA has superior physical properties to Ga-67 and could be of use in the diagnosis of head and neck tumors.

A case of inferior vena cava thrombosis and pulmonary embolism secondary to acute exacerbation of chronic pancreatitis: A rare finding in radionuclide venography

A rare case of inferior vena cava (IVC) thrombosis and pulmonary embolism secondary to acute exacerbation of chronic pancreatitis was reported.Radionuclide venography and lung perfusion scintigraphy were performed on a 46-year-old male with acute exacerbation of chronic pancreatitis who complained of mild swelling of a leg and shortness of breath. Scintigraphy showed an abnormal large hot, spot at the level of the pancreas and a pulmonary embolism. Enhanced abdominal CT revealed an IVC thrombus and a cystic mass adjacent to the IVC. Despite the absence of severe abdominal pain, the serum amylase and elastase-1 levels were very high. These findings indicated that a pancreatic cyst had penetrated into the IVC, where it triggered the formation of a thrombus and caused a pulmonary embolism. Scintigraphic examination was useful for the evaluation of this rare condition.

A comparison of the tumor-seeking agent Tc-99m(V) dimercaptosuccinic acid and the renal imaging agent Tc-99m dimercaptosuccinic acid in humans.

Being aware of the ideal nuclear properties of Tc-99m, our interest has been focused on the design of the (+5) oxidation state Tc-99m(V) dimercaptosuccinic acid (Tc(V)-DMSA) as a tumor-seeking agent. Tc-99m(V) DMSA holds a TcO4 3¯ core and, like PO4 3¯, has excellent characteristics for tumor uptake, but has a different distribution than the well-known renal scanning agent, Tc-99m DMSA. The differences in chemical behavior of Tc-99m(V) DMSA and Tc-99m DMSA are discussed. Three cases in which neoplasms were studies with Tc-99m(V) DMSA and Tc-99m DMSA are presented. Tc-99m DMSA and Tc-99m(V) DMSA, having a common ligand and tracer but, with the metal ion core in a different oxidation state, the uptake characteristics are altered markedly.

SPECT images using99mTc(V)-DMS in lung metastasis of osteosarcoma

Color images of single-photon emission computed tomography (SPECT) using technetium-99m(V) dimercaptosuccinic acid (99mTc(V)-DMS) were demonstrated in a patient with lung metastases from osteosarcoma. SPECT image using99mTc(V)-DMS could be useful for the detection of lung metastasis from osteosarcoma.

Is Ect Imaging with Tc(v)-99m Dimercaptosuccinic Acid Useful to Detect Lung Metastases of Osteosarcoma?

ECT imaging, using Tc(V)-99m dimercaptosuccinic acid [Tc(V)-DMS] was performed in two patients with lung metastasis of osteosarcoma, and the results were compared with those of CT scan. Clear accumulation of Tc(V)-DMS was recognized in all cases in the same area that CT scans demonstrated. Tc(V)-DMS was labeled under optimal pH 8, had very low SnCl2 concentrations, an equilibrium between a stable form and a dissociated form of anion TcO43− structurally similar to PO43−, and was postulated for tumor uptake. Considering this proposed mechanism for Tc(V)-DMS uptake by tumor cells, ECT imaging using this tracer could be of use in the early detection of lung metastasis of osteosarcoma.

A case of diaphragm hernia containing accessory spleen and great omentum detected by Tc-99m phytate scintigraphy.

A rare case of diaphragm hernia containing an accessory spleen and great omentum is reported. Tc-99m phytate SPECT showed tracer accumulation in the accessory spleen and was useful in the evaluation of the disease.

99mTc-MIBI accumulation in the parathyroid autograft in a patient with recurrent hyperparathyroidism.

A case with recurrent hyperparathyroidism secondary to chronic renal insufficiency is reported. The patient had undergone total parathyroidectomy and autotransplantation of parathyroid tissue five years ago. Bone scintigraphy clearly demonstrated skeletal involvement of secondary hyperparathyroidism and99mTc-methoxyisobutylisonitrile scintigraphy clearly demonstrated a hyperfunctioning parathyroid autograft.