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PubMed1989

Analogy between tumor uptake of technetium(V)-99m dimercaptosuccinic acid (DMSA) and technetium-99m-MDP.

Sixty patients with a variety of malignant tumors were examined with Tc-99m(V) dimercaptosuccinic acid (DMSA) prepared by modification of a commercially available DMSA kit. Significant uptake of Tc-99m(V)-DMSA was observed in a number of tumors, offering additional clinically useful information. In the majority of cases in this study, however, the benefit of the Tc-99m(V)-DMSA image was limited because of low sensitivity. The most striking observation was the similarity between the tumor concentration of Tc-99m(V)-DMSA and the Tc-99m-MDP uptake in the tumor on the regular bone image. Therefore, patients with Tc-99m-MDP uptake in nonosseous tumor sites on the bone scan may be suitable candidates for tumor imaging with Tc-99m(V)-DMSA.

Bone and Bones↗
PubMed2003

Technetium-99m DTPA dimethyl ester: a renal function imaging agent. Comparative studies in animals with technetium-99m mercaptoacetyl triglycine and 131I-ortho-iodohippurate.

The dimethyl ester of diethylene triamine penta-acetic acid (DMDTPA) (I) can be easily and efficiently labelled with 99mTc. This method can be readily adapted for kit formulations to produce a highly stable and very pure chelate, as shown by paper electrophoresis and reverse-phase high performance liquid chromatography experiments. In mice, this chelate was excreted unchanged in the urine, and the amount of renal excretion was much higher than that of 99mTc-DTPA and comparable with that of 99mTc-mercaptoacetyl triglycine (99mTc-MAG(3)) at two different time points. The renal excretion of co-injected 131I-ortho-iodohippurate (131I-OIH), however, was significantly greater than that of the 99mTc chelates. The renal clearance values of 99mTc-DMDTPA and 99mTc-MAG(3) were also similar and exceeded the corresponding value for 99mTc-DTPA, but were only half that of the 131I-OIH value in the rat. The renograms for 99mTc-DMDTPA and 99mTc-MAG(3) showed overall similarity in a dog model. The diethyl ester (III) and monoethyl ester (II) of DTPA, after labelling with 99mTc, produced the same chelate, as shown by analytical results and biological data, indicating that one of the ester groups in the DTPA diester is dealkylated during the chelation procedure. To confirm this, two more ligands, diethylene triamine 1,4,7,7-tetra-acetic acid (IV) and diethylene triamine 1,4,7-triacetic acid (V), were synthesized, resembling DTPA monoalkyl ester (II) and dialkyl ester (I, III), respectively, in the arrangement of the donor atoms. Ligand IV but not ligand V, on 99mTc chelation, can generate the specific pharmacophore for renal tubular transport that is also present in the ester chelates 99mTc-I, 99mTc-II and 99mTc-III, as shown by their decreased renal excretion in mice pretreated with a renal tubular transport inhibitor such as probenecid.

Animals↗
PubMed1994

Poor renal uptake of technetium-99m-DMSA and technetium-99m-MDP in a patient with Fanconi syndrome and near normal glomerular filtration rate.

We present a patient with Fanconi syndrome who demonstrated poor renal uptake of 99mTc-DMSA and high urinary concentration of the tracer. A 99mTc-DTPA scan was normal and the creatinine clearance only minimally decreased. These findings suggest that 99mTc-DMSA may be accumulated in the kidney by glomerular filtration and subsequent tubular reabsorption, with the nonabsorbed fraction appearing in the urine. In Fanconi Syndrome the tubular reabsorption of DMSA may also be reduced, thus explaining the poor renal uptake in this patient. A 99mTc-MDP bone scan showed faint renal uptake and diffuse high uptake mainly in the spine, demonstrating that the metabolic bone disease associated with Fanconi Syndrome can be another mechanism for poor renal visualization on bone scan.

Fanconi Syndrome↗
PubMed1992

Radiation dosimetry for technetium-99m-MAG3, technetium-99m-DTPA, and iodine-131-OIH based on human biodistribution studies.

Radiation dose estimates were calculated for the renal agents 99mTc-DTPA, 99mTc-MAG3, and 131I-OIH from biodistribution data gathered in groups of healthy human volunteers. Biokinetics were evaluated by Anger camera imaging, blood sampling, and urine collection and counting. Collected data were fit to four- or five-compartmental models using the CONversational Simulation, Analysis, and Modeling (CONSAM) software. Radiation dose estimates were performed using standard MIRD techniques. Average residence times in urinary bladder, kidney, and remainder of the body were used to predict radiation dose equivalents and effective dose equivalents for the three agents. Doses for DTPA and MAG3 were very similar and much lower on a per unit injected activity than OIH. The effective dose equivalents were 3.3 mSv/370 MBq for 99Tc-DTPA, 3.7 mSv/370 MBq for 99mTc-MAG3, and 0.99 mSv/11.1 MBq for 131I-OIH for bladder voiding every 4.8 hr; effective dose equivalents were 2.0 mSv/370 MBq for 99mTc-DTPA, 1.5 mSv/370 MBq for 99mTc-MAG3, and 0.28 mSv/11.1 MBq for 131I-OIH for bladder voiding at 30 min and then every 4.0 hr. Patients should void at the conclusion of the study, as early voiding can reduce the gonadal radiation dose by a factor of 2 to 3.

Humans↗
PubMed1990

Excretion of iodine-123-hippuran, technetium-99m-red blood cells, and technetium-99m-macroaggregated albumin into breast milk.

The amount of radioactivity excreted in breast milk following three different nuclear medicine procedures on twelve nursing mothers has been measured. Some of this information has already been incorporated into the latest guidelines on suspension of feeding after maternal radiopharmaceutical administration. The overall radiation dose that the patients' babies would have sustained had breast feeding not been interrupted has been estimated as an effective dose equivalent. A model has been developed to describe the relationship between clearance of activity from the milk, time between expressions, and the fraction of milk expressed. Some simple guidance is given on calculation of suitable interruption times for any individual mother from counts on her milk samples.

Erythrocytes↗
PubMed1995

Alveolar integrity in pulmonary emphysema using technetium-99m-DTPA and technetium-99m-HMPAO radioaerosol inhalation lung scintigraphy.

UNLABELLED: The alveolar integrity (AI) in 17 male patients with pulmonary emphysema (EMPH) diagnosed by chest x-ray was measured by 99mTc-DTPA and 99mTc-HMPAO radioaerosol inhalation lung scintigraphy. METHODS: The patients were divided into two groups: (A) nine patients with pulmonary emphysema and normal carbon monoxide diffusion capacity (DLCO) and (B) eight patients with pulmonary emphysema and abnormal DLCO. The degree of AI damage in EMPH was presented as the slope of the time-activity curves from the dynamic left lung imagings in DTPA and HMPAO. The AI of EMPH patients were compared with the AI of 16 normal controls. RESULTS: The results show that: (1) the slope of DTPA is larger than that of HMPAO in each of the portions of the left lung for any of the study groups; (2) statistical differences were found between the normal controls and EMPH patients in HMPAO but not in DTPA; and (3) the correlation was not good between DLCO and DTPA/HMPAO in EMPH patients. CONCLUSION: Our results suggest that: (1) at least two different mechanisms in the lungs were at work; (2) the AI damage in EMPH developed mainly in the lipophilic part of the alveoli; and (3) the AI damage presented as slopes of DTPA/HMPAO in our study was different from the traditional pulmonary function such as DLCO.

Administration, Inhalation↗
PubMed1995

Feasibility of first-pass radionuclide angiocardiography with a 10-mCi technetium bolus using a single-crystal digital gamma camera: implications for technetium-sestamibi single-day protocols.

To test the feasibility of rest first-pass radionuclide angiocardiography (FPRNA) using a 370-MBq (10-mCi) bolus and a single-crystal gamma camera, 40 patients underwent both FPRNA and equilibrium radionuclide angiocardiography (ERNA). Ejection fraction (EF) and regional wall motion (RWM) were assessed by three observers. The interobserver reproducibility was good: the intraclass correlation coefficient was 0.97 for both techniques. The correlation coefficient between FPRNA and ERNA EFs ranged between 0.90 and 0.92. FPRN EFs were significantly higher (P < 0.003) by less than 5 percentage points, this difference having no clinical implications for patient classification. The study provides arguments as to why this difference may be explained self-attenuation rather than counts statistics problems. Both techniques were concordant for RWM analysis. We conclude that FPRNA with 10 mCi is a reliable tool to assess rest left ventricular function, which makes it possible to perform simultaneously myocardial perfusion and function assessment in a single-day protocol using a single-crystal gamma camera.

Feasibility Studies↗
PubMed1990

Comparison of technetium 99m-phytate and technetium 99m-sulphur colloid in primary bone tumours.

Eleven patients with proven primary bone tumour (five Ewing sarcomas, six osteosarcomas) and two cases of metastatic bone involvement (primary other than bone) were investigated with 99mTc-phytate and 99mTc-sulphur colloid to compare the behaviour of the two radiopharmaceuticals at the tumour site. After intravenous administration of the respective radiopharmaceutical, imaging of the tumour site and its contralateral part was carried out at 15 min and 1 h intervals. The data were stored in our computer. Bone scanning was also carried out in all patients. 99mTc-phytate uptake was observed at the tumour site in ten cases. The 99mTc-sulphur colloid study revealed sparse or no significant uptake in eight cases. In two patients, with osteosarcoma 99mTc-sulphur colloid investigation showed uptake at the primary tumour site. However, the distribution pattern is different from that of 99mTc-phytate. No significant uptake of either 99mTc-phytate or 99mTc-sulphur colloid was observed in the two patients with metastatic skeletal disease. It may be concluded that the unusual accumulation of 99mTc-phytate at the tumour site is not due to any generalized reticuloendothelial phenomenon and that the radiopharmaceutical itself is responsible for this.

Adolescent↗
PubMedDate not supplied

Synthesis, characterization, and biological evaluation of neutral nitrido technetium(V) mixed ligand complexes containing dithiolates and aminodiphosphines. A novel system for linking technetium to biomolecules.

A new biomolecule labeling method that utilizes the [(99m)Tc(N)(PNP)](2+) metal fragment is presented. Thus, a series of nitrido mixed-ligand M(V) complexes (M = (99m)Tc, (99g)Tc, Re), [M(N)(Ln)(PNP)], where Ln is the dianionic form of a dithiolate or substituted-dithiolate ligand and PNP is an aminodiphosphine, is described. (99m)Tc complexes can be prepared using either a two-step or a three-step procedure starting from generator-eluted pertechnetate through a prereduced mixture of [(99m)Tc(N)]-containing species, followed by sequential or contemporary addition of the relevant dithiolate and aminodiphosphine. The reactions of 2,3-dimercaptopropionic acid (H(2)L1) with [Tc(N)(PNP)](2+) were investigated in detail. It was found that this bidentate ligand coordinated the metal fragment through the [S(-),S(-)] donor atom pair, to yield neutral mixed-ligand complexes [(99m)Tc(N)(L1)(PNP)] in high specific activity. The additional carboxylic functional group was not involved in metal coordination, thus remaining available for conjugation to target-specific molecules. Dithiolates incorporating pendant functional group(s) gave rise to a 1:1 diastereoisomeric mixture of syn-[M(N)(Ln)(PNP)] and anti-[M(N)(Ln)(PNP)] derivatives, depending on the relative orientation of the dithiolate substituent(s) with respect to the terminal nitrido group, and no isomeric conversion was detected. (99m)Tc species had been proven to be identical with the (99g)Tc complexes prepared at the macroscopic level by comparison of the corresponding radiometric and UV/vis HPLC profiles. Challenge experiments with cysteine or glutathione indicated that these physiological agents had no effect on the stability of this class of mixed-ligand (99m)Tc-complexes. Biodistribution studies in rats of selected (99m)Tc-complexes showed a rapid clearance from the blood and tissues after 60 min pi.

Animals↗
PubMed2006

Phytate technetium-99m versus dextran 500 technetium-99m in the sentinel lymph node biopsy.

PURPOSE: To study which of the two most used radiopharmaceutical drugs for the sentinel lymph node (SLN) biopsy procedure (dextran 500 99mTc and phytate 99mTc) best defines the SLN and migrates less to other lymph nodes. MATERIAL AND METHODS: Thirty-two rats, separated into two groups, underwent lymphoscintigraphy examination with either dextran or phytate followed by sentinel (popliteal), lumbar, and inguinal lymph node biopsy. Radiation was detected with a gamma probe. RESULTS: The statistical study indicated count rates significantly higher in the SLN than in the other basins for both the dextran (P<0.01) and phytate groups (P<0.001). There was no statistically significant difference concerning SLN absorption in either group (P=0.2981). In the dextran group, migration occurred to 1.5 lymphatic basins with counting higher than 10% of that found in the SLN versus 0.8 in the phytate group (P=0.0023). Migration was thus higher in the dextran group (P=0.0207). CONCLUSION: There was no statistically significant difference between dextran and phytate in the SLN identification, but the phytate migrated to fewer lymphatic basins beyond the SLN and with less intensity.

Animals↗