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A cyclotron is a particle accelerator, which employs electromagnetic fields to accelerate charged particles to extremely high speeds and energy. It is used to create radioisotopes for radiopharmaceuticals, which are used to diagnose and treat cancer. Because cyclotron-produced radiopharmaceuticals are exceptionally effective in identifying various cancers. Cyclotrons are fast evolving and will play an increasingly important role in the healthcare industry, particularly in advanced medical imaging techniques like positron emission tomography-computed tomography (PET-CT) and single photon emission computed tomography (SPECT). An 18/9 MeV cyclotron (18 MeV for proton and 9 MeV for deuteron, Model: Cyclone 18/9, IBA) was installed at the National Institute of Nuclear Medicine and Allied Science (NINMAS), Bangladesh Atomic Energy Commission (BAEC). Radioisotopes such as 18F, 11C, 13N, and 15O can be produced with this cyclotron. Solid target option is also available here which can be used for producing 67Ga, 68Ga, 124I, 123I, 111In, 99mTc, 64Cu, and 89Zr radioisotopes. 18F is the radioisotope of choice for many radiopharmaceuticals due to its glucose analogous and half-life of 110 min. We are producing FDG on a regular basis. For a 60-minute bombardment time, a 40 to 50 micro amp beam current is employed to produce 18F with a mass of 2500 to 3500 mCi. Because of the variable production parameters used, the production of 18F varies. Parameters used in the production of 18F radioisotope are limited to physical factors such as target material, target volume, collimator, stripper foil, and ion source. As a result, we consider 18F yield to be the most important aspect in providing sufficient activity since we want to find the best operating point that minimizes both production time and cost. In order to produce an optimal 18F radioisotope production, all parameters such as dee voltage, vacuum label, beam current, irradiation time, amount of enriched 18O water, target pressure, and others are taken into account. Dhaka Univ. J. Sci. 71(1): 56-59, 2023 (Jan)

Background: Newborn screening programs signify early and presymptomatic detection of treatable disorders which authorize commencement of prompt medication to alleviate notable fatality. Newborn screening (NBS) for congenital hypothyroidism (CH) has been a successful public health initiative in preventive medicine over the last few decades. Previous pilot (1999-2006) and phase 1 (2006-2011) NBS program in Bangladesh reported an increased incidence compared to global data which urged to initiate a second phase NBS program for the detection of CH. Materials & Methods: Neonates’ blood was collected from the umbilical cord or by heel prick and drawn on the Guthrie filter paper card. Thyroid-stimulating hormone (TSH) was measured from this filter paper by Immunoradiometric assay (IRMA) or Dissociation Enhanced Lanthanide Fluorescence Immunoassay (DELFIA) method. Results: 123 out of 2,61,550 neonates have already been diagnosed with congenital hypothyroidism from September 2018 to August 2020, which represents an incidence of 1:2126. Conclusion: Ongoing phase-2 project data is already showing some optimistic outcomes. Hence, a time-worthy sustainable policy should be implemented to mark this program as an effective one. Bangladesh J. Nuclear Med. 25(1): 15-21, 2022

Newborn Screening for the diagnosis of Congenital Hypothyroidism (CH) was first started in Bangladesh in 1999 by the Immunoradiometric assay (IRMA). Dissociation enhanced lanthanide fluorescent immunoassay (DELFIA) was started in 1986 due to its superior sensitivity, speed, and non-radioactive methodology. Auto DELFIA 1235 automatic immunoassay system was introduced in the In vitro Division of National Institute of Nuclear Medicine & Allied Sciences (NINMAS) under the ADP Project “Screening of Congenital Hypothyroidism in Newborn Babies (Phase 2)”. It is an automatic system that can minimize the pipetting error. In this experiment, dried blood spots (DBS) were punched into an antibody-coated microtitration well with an automated Panthera Puncher and analyzed by AutoDELFIA. Six different standards of 0.8, 10.3, 24.5, 49.3, 93.2, 239μU/mL were used and the calibration curve was drawn by using these standards. Standard error and Standard deviation were found 12.4 and 30.5. Limit of detection (LOD) and Limit of Quantification (LOQ) of X variables were 0.16 and 0.47. The average of the percent recovery was 96.7. The R2 value of the calibration curve was 0.9985. The accuracy of the standard samples was 96.7 ±10.6. For this assay two Quality Control (QC) of 16.39 μU/mL and 63.09, μU/mL were used. All of the measured values from the calibration curve were close to ±1 standard deviation. All these findings indicate appropriateness of Auto DELFIA System for the CH screening from dried blood spots in the newborn screening laboratory of the In vitro division of NINMAS. Bangladesh J. Nuclear Med. 23(1&2): 15-20, 2020

PET-CT (positron emission tomography and computed tomography) is a gold-standard cancer imaging tool for diagnosis and management, as well as prognostic information based on treatment. Positron-emitting radionuclide 18F (Fluorine) is generated by accelerating particles to energies high enough to cause a certain nuclear reaction 18O(p,n)18F within the particle accelerator, the cyclotron. Mannose triflate is converted to 2-[18F] Fluoro-2-deox-D-yglucose ([18F]FDG) via nucleophilic reaction. Under the ownership of Bangladesh Atomic Energy Commission installed a medium energy (18/9 MeV, IBA) Cyclotron at National Institute of Nuclear Medicine and Allied Sciences (NINMAS). The facility was established in the oncology Building (Block F) of Bangabandhu Sheikh Mujib Medical University (BSMMU). Cyclotron vault and the Control room are located in the underground i.e. basement floor. Each wall of the cyclotron vault and ceiling is made of concrete with a density of 2.35 g/cm3 and a thickness sufficient to shield gamma and neutron radiation. On the ground floor, there are Synthesis room, Quality control laboratory, and the Decontamination room. PET-CT rooms are located on the first floor. Identification, Radionuclide purity (Gamma spectrum detection and half-life measurement), Radiochemical Purity, Chemical purity, Residual solvent measurement, pH measurement, Sterility, and bacterial endotoxins (LAL test) are performed to maintain the quality of the product. The current uses of the Cyclotron are mostly for the synthesis of 18F-FDG. Bangladesh J. Nuclear Med. 24(1&2): 48-50, 2021

211At was produced in the 209Bi(4He, 2n)211At reaction. The yield was separated from the irradiated bismuth target by a simple method, based on dry distillation. The optimized conditions of the method were studied by monitoring the astatine radioactivity with gamma-ray spectrometers. The no-carrier-added 211At solutions were prepared with eluents, namely distilled water, ethanol, methanol, or chloroform. Generally, the recovery yields obtained with the utilization of 1.6 mL of the eluent were 26–75%. The prepared 211At solutions were subjected to thin-layer chromatography and high-performance liquid chromatography to identify the chemical species present.

211At was produced in the 209Bi(4He, 2n)211At reaction. The yield was separated from the irradiated bismuth target by a simple method, based on dry distillation. The optimized conditions of the method were studied by monitoring the astatine radioactivity with gamma-ray spectrometers (GRSs). The no-carrier-added 211At solutions were prepared with eluents, namely distilled water, ethanol, methanol, or chloroform. Generally, the recovery yields obtained with the utilization of 1.6 mL of the eluent were 26-75%. The prepared 211At solutions were subjected to thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) to identify the chemical species present.

The 211At-labeled compound, 4-[211At]astato-L-phenylalanine, is one of the most promising amino acid derivatives for use in targeted alpha therapy (TAT) for various cancers. Electrophilic demetallation of a stannyl precursor is the most widely used approach for labeling biomolecules with 211At. However, the low acid-resistance of the stannyl precursor necessitates the use of an N- and C-terminus-protected precursor, which results in a low overall radiochemical yield (RCY) due to the multiple synthetic steps involved. In this study, a deprotected organosilyl compound, 4-triethylsilyl-L-phenylalanine, was employed for the direct synthesis of astatinated phenylalanines. 211At was separately recovered from the irradiated 209Bi target using chloroform (CHCl3) and N-chlorosuccinimide-methanol (NCS-MeOH) solution. The RCYs of 4-[211At]astato-L-phenylalanine obtained from the triethylsilyl precursor with the use of 211At, isolated in CHCl3 and NCS-MeOH solution, were 75% and 64% respectively. In both cases, the retention time of the 4-[211At]astato-L-phenylalanine was found to be about 20 min, which showed reasonable correlation with the retention time of non-radioactive 4-halo-L-phenylalanines (4-chloro-, 4-bromo-, and 4-iodo-L-phenylalanine). The one-step reaction examined in this study involved mild reaction conditions (70 °C) and a short time (10 min) compared to the other currently reported procedures for astatination. Electrophilic desilylation was found to be very effective for the labeling of aromatic amino acids with 211At.

The 211At-labeled compound, 4-[211At]astato-L-phenylalanine, is one of the most promising amino acid derivatives for use in targeted alpha therapy (TAT) for various cancers. Electrophilic demetallation of a stannyl precursor is the most widely used approach for labeling biomolecules with 211At. However, the low acid-resistance of the stannyl precursor necessitates the use of an N- and C- terminus-protected precursor, which results in a low overall radiochemical yield (RCY) due to the multiple synthetic steps involved. In this study, a deprotected organosilyl compound, 4-triethylsilyl-L-phenylalanine, was employed for the direct synthesis of astatinated phenylalanines. 211At was separately recovered from the irradiated 209Bi target using chloroform (CHCl3) and N-chlorosuccinimide-methanol (NCS-MeOH) solution. The RCYs of 4-[211At]astato-L-phenylalanine obtained from the triethylsilyl precursor with the use of 211At, isolated in CHCl3 and NCS-MeOH solution, were 75% and 64% respectively. In both cases, the retention time of the 4-[211At]astato-L-phenylalanine was found to be about 20 min, which showed reasonable correlation with the retention time of non-radioactive 4-halo-L-phenylalanines (4-chloro-, 4-bromo-, and 4-iodo-L-phenylalanine). The one-step reaction examined in this study involved mild reaction conditions (70 °C) and a short time (10 min) compared to the other currently reported procedures for astatination. Electrophilic desilylation was found to be very effective for the labeling of aromatic amino acids with 211At.

Chemiluminescence immunoassay (CLIA) has been widely applied in different fields including environmental monitoring, liquid chromatography, clinical diagnosis; food safety, pharmaceutical analysis, immuno- and gene probe assays, as a promising approach for selective, sensitive, rapid and simple analysis. It is often necessary to detect a large number of complicated or low-abundance samples. However, traditional methods need great consumption of time, reagents and labor, which limit their clinical applications. As a result, rapid, high-throughput, sensitive and low-cost detection methods have become the development trend of CLIA. A new chemiluminescence immunoassay analyzer with advanced acridinium ester (AE) technology will be installed at the radioimmunoassy laboratory of National Institute of Nuclear Medicine and Allied Sciences (NINMAS) shortly. In conjunction with the existing Radioimmunoassay (RIA), Immunoradiometric assay (IRMA) and DissociationEnhanced Lanthanide Fluorescent Immunoassay (DELFIA), introduction of chemiluminescence immunoassay (CLIA) technology will expand the activities of in vitro immunoassay. It will also improve the research and development activities of in vitro division of NINMAS. In this review article, we have summarized the basic principle of chemiluminescence immunoassay and its applications. A comparison of RIA, CLIA and enzyme-linked immunosorbent assay (ELISA) was also briefly described in the article.Bangladesh J. Nuclear Med. 18(2): 171-178, July 2015

The in vitro laboratory of radioimmunoassay (RIA) Division is designed to provide clinical diagnostic service (e.g. hormone assay) and also to facilitate research works related to radioimmunoassay. The in-vitro laboratory is situated at the 9th floor of block-D of Bangabandhu Sheikh Mujib Medical University (BSMMU). Presently the invitro division of National Institute of Nuclear Medicine and Allied Sciences (NINMAS) has 18 man powers including doctors, radiochemists, officers, technologists and other laboratory staffs. The equipments used for RIA in in vitro laboratory are gamma counter, micropipettes, centrifuge, magnetic separators, vortex mixture, incubator/water bath, stirrers, deep freezer, refrigerator, pH Meter, analytical balance, test tubes and laboratory glassware etc.A large number of samples are analyzed by the RIA Lab each week. In the year 2013 - 2014 (1st July 2013 – 30th June 2014), a total of 100 assays were done. A total of 25135 samples were assayed by RIA/IRMA in the in vitro lab. Results are reported on every Monday and Thursday of the week.After careful consideration of the local infrastructure, robustness and cost of nuclear and non-nuclear assays, it is likely that RIA methodology will be the main workhorse of routine laboratory diagnostic services of NINMAS.Bangladesh J. Nuclear Med. 18(1): 64-68, January 2015

The astatine-211 (At-211) labeled compound, 4-[211At]astato-L-phenylalanine, is one of the most promising amino acid derivatives for use in targeted alpha therapy (TAT) for various cancers. Electrophilic demetallation of stannyl precursor is the most widely used approach for labeling biomolecules with At-211. However, the low acid-resistance of the stannyl precursor necessitates the use of a N- and C- terminus protected precursor, which causes low overall radiochemical yield (RCY) due to the multiple synthetic steps involved. A deprotected organosilyl compound, 4-triethylsilylphenylalanine, was employed for direct synthesis of the astatinated phenylalanine in this study., 11th International Symposium on Targeted-Alpha-Therapy (TAT11)

The accuracy of patient specific dosimetry is correlated with measured organ activity by gamma camera and SPECT system. The assessment of the radiation-absorbed dose by patients undergoing nuclear medicine investigation requires accurate measurement of organ activity, biokinetics data, as well as physical data. Activities were estimated by using Ba-133 phantom with both planar and SPECT systems. The objective of the study was to measure the activities of Ba-133 from gamma camera images using both planar and SPECT studies and compare the reference values with the dose calibrator values to quantify the actual activity with gamma camera. Four Ba-133 sources of different volume and activity 379, 950, 1219 and 1150 KBq are measured by using Veenstra Instrument VDC 404 Dose Calibrator. The second smallest source was used to determine the calibration factor. Acquisition, corrections, reconstruction, quantification and measuring activity from both planar and SPECT imaging were done with all Ba-133 sources in air. The activities of the Ba-133 sources were also measured using I-131 settings of the dose calibrator. The measurement of the second smallest source was used to obtain the calibration factor. This calibration factor was used to convert the planer and SPECT image count of all the sources into activities. In case of both planar and SPECT gamma camera, the measurements showed good correlations and all the values varied within ±15%. Planer and SPECT gamma camera image counts can be used to calculate activity in the organ. This information can play a very significant role in evaluating image based patient specific dosimetry in radionuclide therapy.Bangladesh J. Nuclear Med. 17(2): 134-137, July 2014

Introduction: In cholinergic neurons, high affinity choline uptake (HACU) by the high affinity choline transporter (HAChT) is a rate-limiting and regulatory step for the synthesis of Acetylcholine (Ach).Thus, HAChT appear to be a relatively specific presynaptic marker for cholinergic neurons in Alzheimer’s disease. Objectives: The principle objective of the study is to check the affinity of tetrahydroaminoacridine (THA) derivatives for HAChT. Another objective of the research work is to clarify whether the hemicholinium-3 (ChT inhibitor) and HACU enhancer molecules share the same binding sites or not. Materials and Methods: The inhibition activities of tacrine, the 2,3-dimethylfuran derivative of tacrine (DMTA) and their corresponding 2-oxo-1-pyrrolidineacetyl derivatives, namely PTAA and MKC-231 were measured by displacement of a typical HAChT antagonist [ 3 H]HC-3 in rat cerebral membrane. The percentage of inhibition against the binding of [ 3 H]HC-3 to HAChT were calculated using GraphPad Prism v4 software. Results: Hemicholinium-3 showed affinity for HAChT (IC 50 = 20 nM) in the in vitro binding assay. A very insignificant inhibition activity (IC 50 = 1000 nM) of Tacrine was revealed. The newly synthesized tacrine derivatives, DMTA and PTAA did not show any affinity for HAChT. Although MKC-231 was reported to enhance cholinergic activity at synaptic terminals, it did not show any affinity for the HAChT in [ 3 H]HC-3 binding assay. Conclusion: In vitro [ 3 H]HC-3 binding assay revealed no affinity of MKC-231, tacrine and its corresponding2-oxo-1-pyrrolidineacetate derivative towards HAChT. So, it is worthy to develop radiolabeled HC-3 derivatives with high affinity for HAChT, which can diffuse the BBB, to enable the in vivo investigation of HACU system. Bangladesh J. Nuclear Med. 17(2): 97-102, July 2014

Objective: The aim of the present study is to determine the own normal range of T3, T4, FT4, & TSH by two kits, one from Korea and another from China in the laboratory of healthy individuals from different divisions of the Institute.Subjects and Methods: Fifty eight (58) adult individuals (39 male &19 female) from different divisions of NINMAS were taken this study. The Korean kit contained coated tube and automated radioimmunoassays (RIA) were performed in case of the Korean kit. Radioimmunoassays with the China kit were done manually by counting in STRATEC-γ Counter of Germany. Immunoassays of T3, T4, and FT4 were done by RIA method. With both the Korean and Chinese kit, TSH assays were performed by IRMA method.Results: The results are analyzed by determining a mean ± 2SD for the normal range. This assumes a Gaussian distribution for the analyte and automatically classifies 5% of the healthy individuals as abnormal. The normal range of T3, T4, FT4 and TSH done by Korean kit were 0.473732561 – 1.8224543301ng/ml (Leaflet normal range, 0.60–2.10ng/ml), 73.61233952– 152.00007428ng/ml (Leaflet normal range, 45.00 – 120.00ng/ml), 7.407195952 – 21.673838528ng/ml (Leaflet normal range, 9.01 – 23.17ng/ml) and 0.077556152 – 5.462788676µIU/ml (Leaflet normal range, 0.30 – 5.00ng/ml) respectively. The normal range of T3, T4, FT4, and TSH done by China kit were 0.922455645 – 1.929268493ng/ml (Leaflet normal range, 0.80 – 2.30ng/ml), 44.87278419 – 141.23445719ng/ml (Leaflet normal range, 42.00 – 135.00ng/ml), 5.80024859 – 32.72492383Pmol/L (Leaflet normal range, 9.50 – 25.50Pmol/L) and 0.807976292 – 5.77167888mIU/L. (Leaflet normal range, 0.30 – 5.00mIU/L) respectively.Conclusion: By estimating few more samples we may use our won estimated normal ranges instead of the leaflet normal ranges.Bangladesh J. Nuclear Med. 18(2): 149-151, July 2015

The 211At-labeled compound, 4-[211At]astato-l-phenylalanine, is one of the most promising amino acid derivatives for use in targeted alpha therapy (TAT) for various cancers. Electrophilic demetallation of a stannyl precursor is the most widely used approach for labeling biomolecules with 211At. However, the low acid-resistance of the stannyl precursor necessitates the use of an N- and C-terminus-protected precursor, which results in a low overall radiochemical yield (RCY) due to the multiple synthetic steps involved. In this study, a deprotected organosilyl compound, 4-triethylsilyl-l-phenylalanine, was employed for the direct synthesis of astatinated phenylalanines. 211At was separately recovered from the irradiated 209Bi target using chloroform (CHCl3) and N-chlorosuccinimide-methanol (NCS-MeOH) solution. The RCYs of 4-[211At]astato-l-phenylalanine obtained from the triethylsilyl precursor with the use of 211At, isolated in CHCl3 and NCS-MeOH solution, were 75% and 64% respectively. In both cases, the retention time of the 4-[211At]astato-l-phenylalanine was found to be about 20 min, which showed reasonable correlation with the retention time of non-radioactive 4-halo-l-phenylalanines (4-chloro-, 4-bromo-, and 4-iodo-l-phenylalanine). The one-step reaction examined in this study involved mild reaction conditions (70 °C) and a short time (10 min) compared to the other currently reported procedures for astatination. Electrophilic desilylation was found to be very effective for the labeling of aromatic amino acids with 211At.

We focused on the vesicle acetyl choline transporter (VAChT) as target for early diagnosis of Alzheimer's diseases because the dysfunction of the cholinergic nervous system is closely associated with the symptoms of AD, such as problem in recognition, memory, and learning. Due to its low binding affinity for the sigma receptors (σ-1 and σ-2), o-methyl-trans-decalinvesamicol (OMDV) demonstrated a high binding affinity and selectivity for vesicular acetyl choline transporter (VAChT). [(11)C]OMDV was prepared and investigated the potential as a new PET ligand for VAChT imaging through in vivo evaluation.[(11)C]OMDV was prepared by a palladium-promoted cross-coupling reaction using [(11)C]methyl iodide, with a radiochemical yield of 60-75%, a radiochemical purity of greater than 98%, and a specific activity of 5-10 TBq/mmol 30 min after EOB. In vivo biodistribution study of [(11)C]OMDV in blood, brain regions and major organs of rats was performed at 2, 10, 30 and 60 min post-injection. In vivo blocking study and PET-CT imaging study were performed to check the binding selectivity of [(11)C]OMDV for VAChT.In vivo studies demonstrated [(11)C]OMDV passage through the blood-brain barrier (BBB) and accumulation in the rat brain. The regional brain accumulation of [(11)C]OMDV was significantly inhibited by co-administration of vesamicol. In contrast, brain accumulation of [(11)C]OMDV was not significantly altered by co-administration of (+)-pentazocine, a selective σ-1 receptor ligand, or (+)-3-(3-hydroxyphenyl)-N-propylpiperidine [(+)-3-PPP], a σ-1 and σ-2 receptor ligand. PET-CT imaging revealed inhibition of [(11)C]OMDV accumulation in the brain by co-administration of vesamicol.[(11)C]OMDV selectively binds to VAChT with high affinity in the rat brain in vivo, and that [(11)C]OMDV may be utilized in the future as a specific VAChT ligand for PET imaging.

We investigated the characteristics of the regional rat brain distribution of radio-brominated o-bromo-decalinvesamicol (OBDV) in vivo to evaluate its potential as a PET ligand for vesicular acetylcholine transporter (VAChT). In in vivo biodistribution study, the specific brain regional accumulation of [77Br]OBDV was revealed 30 min after intravenous injection. The specific brain regional accumulation of [77Br]OBDV was significantly inhibited by co-injection of (+/−)-vesamicol. In contrast, no significant inhibition of the uptake of [77Br]OBDV in all brain regions was observed with co-injection of (+)-pentazocine (selective σ-1 receptor agonist) and (+)−3-(3-hydroxyphenyl)-N-propylpiperidine, [(+)−3-PPP] (σ-1 and σ-2 receptor agonist) with [77Br]OBDV. [77Br]OBDV accumulation in VAChT-rich brain regions was observed in ex vivo autoradiography. These results showed that [77Br]OBDV selectively bound to VAChT with high affinity in rat brain in vivo. Hence, OVBDV radiolabelled with more suitable 76Br was suggested to be a potent VAChT ligand for PET. Synapse 68:445–453, 2014. © 2014 Wiley Periodicals, Inc.

In this study, the regional rat brain distribution of radioiodinated o-iodo-trans-decalinvesamicol ([125I]OIDV) was determined in vivo to evaluate its potential as a single-photon emission computed tomography (SPECT) imaging probe for vesicular acetylcholine transporter (VAChT). Following intravenous injection, [125I]OIDV passed freely across the blood–brain barrier and accumulated in rat brain. The accumulation of [125I]OIDV in rat brain was significantly reduced by coadministration of (+/−)-vesamicol (0.125 µmol). In contrast, the coadministration of σ-receptor ligands, such as (+)-pentazocine (0.125 µmol) as a σ-1 receptor ligand and (+)−3-(3-hydroxyphenyl)-N-propylpiperidine (0.125 µmol) as a σ-1 and σ-2 receptor ligands, barely affected the accumulation of [125I]OIDV in rat brain. These findings in vivo were corroborated by autoradiographic analysis ex vivo. The authors found that the tracer binds with pharmacological selectivity to VAChT in rat brain and predicted that it may likewise serve in translational SPECT imaging studies of this marker in the integrity of cholinergic innervations. Synapse 68:107–113, 2014. © 2013 Wiley Periodicals, Inc.

We investigated the characteristics of the regional rat brain distribution of radio-brominated o-bromo-decalinvesamicol (OBDV) in vivo to evaluate its potential as a PET ligand for vesicular acetylcholine transporter (VAChT). In in vivo biodistribution study, the specific brain regional accumulation of [(77) Br]OBDV was revealed 30 min after intravenous injection. The specific brain regional accumulation of [(77) Br]OBDV was significantly inhibited by co-injection of (+/-)-vesamicol. In contrast, no significant inhibition of the uptake of [(77) Br]OBDV in all brain regions was observed with co-injection of (+)-pentazocine (selective σ-1 receptor agonist) and (+)-3-(3-hydroxyphenyl)-N-propylpiperidine, [(+)-3-PPP] (σ-1 and σ-2 receptor agonist) with [(77) Br]OBDV. [(77) Br]OBDV accumulation in VAChT-rich brain regions was observed in ex vivo autoradiography. These results showed that [(77) Br]OBDV selectively bound to VAChT with high affinity in rat brain in vivo. Hence, OVBDV radiolabelled with more suitable (76) Br was suggested to be a potent VAChT ligand for PET.

In this study, the regional rat brain distribution of radioiodinated o-iodo-trans-decalinvesamicol ([(125) I]OIDV) was determined in vivo to evaluate its potential as a single-photon emission computed tomography (SPECT) imaging probe for vesicular acetylcholine transporter (VAChT). Following intravenous injection, [(125) I]OIDV passed freely across the blood-brain barrier and accumulated in rat brain. The accumulation of [(125) I]OIDV in rat brain was significantly reduced by coadministration of (+/-)-vesamicol (0.125 µmol). In contrast, the coadministration of σ-receptor ligands, such as (+)-pentazocine (0.125 µmol) as a σ-1 receptor ligand and (+)-3-(3-hydroxyphenyl)-N-propylpiperidine (0.125 µmol) as a σ-1 and σ-2 receptor ligands, barely affected the accumulation of [(125) I]OIDV in rat brain. These findings in vivo were corroborated by autoradiographic analysis ex vivo. The authors found that the tracer binds with pharmacological selectivity to VAChT in rat brain and predicted that it may likewise serve in translational SPECT imaging studies of this marker in the integrity of cholinergic innervations.