Iranian Journal of Nuclear Medicine
Volume:20 Issue: 1, Winter-Spring 2012

In this study the automatic separation of oral and salivary gland activity and spontaneous secretion by means of factor analysis for quantitative salivary gland scintigraphy is introduced. After intravenous administration of 99mTc sodium pertechnetate, dynamic scintigraphy was performed. 20 minutes after tracer application 2 ml of lemon juice was delivered to stimulate the glands. Applying elliptical regions of interest for oral cavity and four major salivary glands and using factor analysis of medical image sequences (FAMIS) results in factor images and curves, which are used for quantification of the oral, sublingual and glandular activity indexes. With FAMIS it is possible to automatically separate the three superimposed processes seen in salivary gland scintigraphy: glandular and oral activity and spontaneous secretion that results in significant different quantitative results. The application of factor analysis improves the results of salivary gland scintigraphy by separation of superimposed dynamic processes of oral and glandular activity and spontaneous secretion.

The key characteristics of positron emission tomography (PET) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. Therefore, accurate quantification is important. However, it can be sensitive to several physical factors. The aim of this investigation is the assessment of the effect of physical effects, such as: scatter coincidences, partial volume, positron range and non-colinearity on the quantification of FDOPA uptake using PET. The SimSET Monte Carlo package was employed to simulate acquisitions of the PET/CT Siemens Biograph scanner. The study was performed with a numerical brain model obtained from the CT scan of a commercial striatal phantom. Theoretical pharmacokinetic values were simulated. The simulations were carried out with and without scatter, positron range and non-colinearity effects. The OSEM algorithm from STIR library was used to reconstruct the PET data. Different correction strategies were employed in order to evaluate the effects caused by the different type of degradation on results obtained with Patlak analysis. The FDOPA uptake of Patlak plot increased from 70.4% of the theoretical value to 80.4%, if scatter was perfectly corrected, and it increased to 99% of the theoretical value when the partial volume correction was employed, as well. No significant improvement was found for positron range and non-colinearity effects when the partial volume correction was employed. The results show that the compensation for scatter and partial volume degradations increases accuracy in the uptake calculation.

Due to interesting therapeutic properties of 46Sc and antineoblastic antibiotic, bleomycin (BLM), 46Sc-bleomycin (46Sc-BLM) was developed as a possible therapeutic compound. In this work, Sc-46 chloride was obtained by thermal neutron flux (4 × 1013 n.cm-2.s-1) of natural metallic scandium sample followed by dissolution in acidic media as a substitute for 47Sc in radiolabeling studies which was further used for labeling of bleomycin (BLM) followed by stability studies as well as biodistribution in wild-type rats. Sc-46 was obtained in high radiochemical purity (ITLC, >99%, two systems) as well as acceptable specific activity. At optimized conditions a radiochemical purity of 98% was obtained for 46Sc-BLM shown by ITLC (Specific activity, 740 GBq/mmole). The accumulation of the radiolabeled compound in lungs, liver and spleen demonstrates a similar pattern to the other radiolabeled bleomycins. Sc-BLM is a possible therapeutic agent in human malignancies and the efficacy of the compound should be tested in various tumor-bearing models.

5-HT1A receptor is related with a variety of neuropsychiatric disorders.. In this study a phenolic analogue derived from DWAY [Desmethyl WAY-100635 (N-(2-(1-(4-(2-methoxyphenyl)piperazinyl)-ethyl))-N-(2-pyridinyl) cyclohexanecarboxamide)] is used to design the desired structure of 5-HT1A receptor imaging agents after labeling with [99mTc (CO) 3(H2O) 3] + core via dithiocarbamate moiety. 2-(piperazin-1-yl) phenol Dithiocarbamate was synthesized by the reaction of 2-(piperazin-1-yl) phenol with an equivalent amount of carbon disulfide in KOH solution then radiolabeled with [99mTc(CO)3(H2O)3]+ core. Radioligand chemical analysis involved high-performance liquid chromatography methods. Radioconjugate stability and lipophilicity were determined. Biodistribution of labeled compound was studied in rats. The final complex was characterized by HPLC and its radiochemical purity was more than 90%. In vitro stability studies have shown the complex was stable at least 6-hrs after labeling at room temperature. The n-octanol/water partition coefficient experiment demonstrated Log P = 0.74 for 99mTc(CO)3-OH-PP-CS2. Biodistribution results showed that radio tracer had moderate brain uptake (0.32 ± 0.03 %ID/g at 30 min post injection), This complex may lead to a further development of a radiotracer with specific binding to 5-HT1A receptor.

The purpose of the present study was to evaluate the effect of prednisolone on the sensitivity of bone scanning to detect the simulated closed fracture in the rat tibia. A total number of forty eight adult, male NMRI rats randomly assigned into two parts, one part for 4 and other for 8 weeks experiments. Each part has been divided into four groups, one group not receiving prednisolone (control group) and the other groups receiving 5, 10 and 20 mg/kg prednisolone respectively. After four and eight weeks of experiments a simulated closed fracture was created in the tibia approximately 1 cm near knee joint.. The scintigraphy imaging has been performed on second and fifth day after tibial bone fracture and the ratio of the activity of tibia bone fracture to the contra lateral healthy side was calculated (R factor). All scintigraphy images showed the rat tibia bone fracture. Statistically significant difference in the R factors have been observed, when scintigraphy images were performed in fifth day after injury. Bone radionuclide scanning by 99mTc-MDP is very sensitive for detection of occult fracture. In order to enhance bone scan sensitivity, it may be reasonable to postpone 99mTc-MDP scintigraphy imaging at least 2 to 3 days after suspected trauma in patients receiving glucocorticoid medication.

In the current study, we compared the h-indices of Web of Science (WOS), SCOPUS, and GS of the Iranian nuclear medicine scientists Full time members of two major nuclear medicine research centers of Iran with more than 5 year of experience (Nuclear Medicine Research Center of Mashhad University of Medical Sciences, and Research Institute for Nuclear Medicine of Tehran University of Medical Sciences) were included for h-index evaluation. H-indices of SCOPUS, WOS and GS were retrieved using their specific websites. Correlations of h-indices with each other were evaluated using spearman correlation coefficient. Overall 11 researchers were included in the study. SCOPUS, WOS, and GS provided somehow different h-indices for each researcher. Spearman's correlation coefficients between different h-indices were high: 0.834, 0.817, 0.857 between SCOPUS and WOS, SCOPUS and GS, and GS and WOS respectively. Rankings of researchers according to different database however, were acceptably identical. H-indices provided by SCOPUS, Web of Science WOS, and Google Scholar (GS) for Iranian nuclear medicine researchers can be used interchangeably. However these h-indices can be different according to which database is used. Setting up “ReasercherID” in WOS and “User profile” in GS, as well as giving regular feedback to SCOPUS managers can increase the accuracy of h-indices calculation.

Parathyroid adenoma involving a single parathyroid gland is the underlying cause of 80-85% of primary hyperparathyroidism (PHPT). Skeletal system is significantly affected by PHPT. Brown tumors are known to have affinity for 99mTc-MIBI. We report a rare case of PHPT presenting with diffuse bony pain, high calcium level and significantly elevated alkaline phosphatase level. 99mTc-pertechnetate/99mTc-MIBI subtraction, performed as a part of routine protocol, showed several brown tumors showing affinity for both 99mTc-pertechnetate and 99mTc-MIBI. They were further characterized using hybrid SPECT/CT. To the best of our knowledge, 99mTc-pertechnetate affinity in brown tumors has not been previously described.

We report here a rare case of lateral ectopia of thyroid without orthotopic thyroid tissue in an Indian teenager, who was referred to our department for a thyroid scintigraphy. Technetium Pertechnetate (99mTcO4-) scan showed uptake in laterally placed soft tissue structure along with functioning thyroid tissue in high anterior midline neck region in line with thyroglossal tract. There is no uptake in the normal anatomical thyroid bed region. Ultrasound study of the neck confirmed a soft tissue structure on the right of midline appearing coarse in echotexture with internal vascularity and absent native thyroid gland. Ectopic thyroid tissue lateral to midline associated with thyroglossal tract remnant and absence of orthotopic thyroid tissue is known to be very rare.

The principle of cancer immunotherapy includes various methods of manipulations to influence immune responses against tumors in both humans and animals. This advanced technology of hybridoma production provided the necessary skills to efficiently produce highly specific monoclonal antibodies (mAb). Radioactively-tagged antibodies which are applied in radioimmunotherapy (RIT), can target adjacent cells and may not require immune function. This study highlights the mechanism and the effect of action of radioimmunotherapic agents, especially two applied agents including 90Y-ibritumomab tiuxetan and 131I-tositumomab that are approved by Food and Drug Administration (FDA) for treatment of some cancers.