Application Of Radiotracers Research Articles

Industrial radiotracer application in flow rate measurement and flowmeter calibration using 99mTc and 198Au nanoparticles radioisotope

The flow rate or fluid velocity measurement is important to maintain fluid flow quality performance in the systems. This study focuses on determination of volumetric flow rate measurement and to calibrate the conventional flowmeter using industrial radiotracer approach in quadrilateral gas-liquid bubble column reactor. In this work, two different radioisotopes which emit γ-ray have been chosen as radioactive tracer which is 99mTc produced from 99Mo/99mTc radioisotope generator and 198Au nanoparticle form neutron activation at research nuclear reactor TRIGA Mark II. Both radioisotopes representing liquid and solid tracer purposely designed for tracing liquid flow. The peak to peak radiotracer method known as pulse velocity method was applied to determine the volumetric flow rate. The radiation signals were monitored using 4 unit NaI scintillation detectors located at 4 different points nearby the inlet and outlet of the quadrilateral bubble column reactor process stream. The water volume inside the bubble column reactor was fixed at 0.04 m3 and liquid flow rates in this reactor were specified on installed flowmeter at different reference value which is 4 lpm, 8 lpm, and 12 lpm, respectively. The experimental result shows very good linearity and repeatability by following the theoretical equations with less uncertainty in volumetric flow rate measurement. The obtained results also validated the effectiveness of the proposed method for the installed flowmeter calibration efficiency.

Flow dynamics study of catalyst powder in catalytic cracking unit for troubleshooting

Abstract Gamma scanning and radiotracer applications are very effective and inexpensive tools to understand and optimize the process as well as troubleshoot the various types of problems in many chemical, petrochemical industries and refineries. These techniques are non-invasive; hence, the problems can be pinpointed online, which leads to reduce the downtime, schedule the shutdown and maintenance of the plant equipment, rendering huge economic benefits. In a leading refinery of India, the catalytic cracking unit (CCU) was malfunctioning. It was suspected by the refinery engineers that the catalyst powder was being carried over to the fractionator, which could have led to erosion of the fractionator column internals resulting in their rupture, and consequentially, to the fire hazard. To understand the flow behaviour of the catalyst powder and to ensure the mechanical integrity, catalyst accumulation and choking, both radiotracer study and gamma scanning of the CCU reactor was carried out. The reactor consists of a riser, three primary cyclones and three secondary cyclones. Gamma scanning of the reactor was carried out with the help of an automatic gamma scanner using 1.8 GBq of Co-60 sealed source. Results showed that the catalyst powder was accumulated in one of the secondary cyclones and uneven density distribution was observed in another secondary cyclone. The radiotracer study was carried out using the irradiated catalyst powder as a radiotracer, which contains 0.9 GBq of Na-24. The radiotracer was injected in the reactor through the specially fabricated injection system. Radiation measurement was done using the thermally insulated and collimated NaI(Tl) scintillation detectors located at various strategic locations coupled to a multi-detector data acquisition system. The data were mathematically analysed. It was confirmed that the catalyst powder was accumulated in one of the secondary cyclones with no flow downwards. This resulted in excess powder available to travel along with hydrocarbon towards fractionator. Since the quantity of powder released through the hydrocarbon outlet of CCU was higher than the designed value, the catalyst powder was observed in various zones of the fractionator. Mathematical modelling of the radiotracer data obtained at various locations corroborated the scanning results; also, the flow pattern was obtained. Partially blocked secondary cyclone showed plug flow with recirculation; normal working cyclone had plug flow behaviour and the vortex breaker showed parallel flow.

Radiological and nuclear medicine imaging of sarcoidosis.

Sarcoidosis is a multisystem chronic inflammatory disease of unknown etiology characterized by widespread growth of non-caseating granulomas. The diagnosis of sarcoidosis is based on clinical and imaging presentation, histologic confirmation and the absence of alternative diseases. Radiology and Nuclear Medicine play an essential role in the diagnostic work-up of patients with sarcoidosis to assess disease extent and activity. In addition, imaging modalities have shown their potential in managing these patients in terms of treatment response and prognostic assessment. Sarcoidosis has a predilection for chest involvement, showing typical and atypical manifestations in the lungs, airways and hilar/mediastinal lymph nodes. Chest radiography (X-ray) still plays an important role in suggesting diagnosis for cases with typical presentation of sarcoidosis, while computed tomography (CT) has higher accuracy in detecting early stage disease and in narrowing differential diagnosis, particularly in atypical manifestations. For extrathoracic involvement, both CT and MR (magnetic resonance) have comparable performance even though MR is the modality of choice for assessing neurosarcoidosis and cardiac sarcoidosis. In the last decades positron emission tomography/CT (PET/CT) has demonstrated an increasing and relevant value in assessing disease extent and activity, treatment planning and therapy response, with a crucial role in the management of cardiac sarcoidosis. In this article, an overview of the possible imaging manifestations of thoracic and extrathoracic sarcoidosis and current concepts on staging, response assessment and prognosis is provided. Finally, the potential applications of non-FDG radiotracers is briefly discussed.

Hypoxia-induced tumor biological behavior changes and application of radiotracers for PET imaging of tumor hypoxia

Hypoxia exists in a wide range of advanced solid tumors and is often associated with poor prognosis. Hypoxia can enhance tumor invasion, promote tumor angiogenesis, impact genomic stability and change the tumor microenvironment by activating expression of relevant genes through hypoxia-induced factors (HIFs). Hypoxia provides favorable conditions for tumor metastasis and relapse, and it is involved in all aspects of tumor development. The study of hypoxia in tumors may provide useful information for pre-clinical evaluation, individualized treatment and clinical prognosis. Positron emission tomography (PET) is a non-invasive imaging method, which can be used for assessing and quantifying tumor hypoxic microenvironment. This article reviews the mechanisms of hypoxia-induced tumor biological behavior changes and the research progress of the application of radiotracers for PET imaging of tumor hypoxia. Key words: Cell hypoxia, neoplasms; Hypoxia-inducible factor 1, alpha subunit; Radioactive tracers

Quantitative experimental monitoring of molecular diffusion in clay with positron emission tomography

Abstract. Clay plays a prominent role as barrier material in the geosphere. The small particle sizes cause extremely small pore sizes and induce low permeability and high sorption capacity. Transport of dissolved species by molecular diffusion, driven only by a concentration gradient, is less sensitive to the pore size. Heterogeneous structures on the centimetre scale could cause heterogeneous effects, like preferential transport zones, which are difficult to assess. Laboratory measurements with diffusion cells yield limited information on heterogeneity, and pore space imaging methods have to consider scale effects. We established positron emission tomography (PET), applying a high-resolution PET scanner as a spatially resolved quantitative method for direct laboratory observation of the molecular diffusion process of a PET tracer on the prominent scale of 1–100 mm. Although PET is rather insensitive to bulk effects, quantification required significant improvements of the image reconstruction procedure with respect to Compton scatter and attenuation. The experiments were conducted with 22Na and 124I over periods of 100 and 25 days, respectively. From the images we derived trustable anisotropic diffusion coefficients and, in addition, we identified indications of preferential transport zones. We thus demonstrated the unique potential of the PET imaging modality for geoscientific process monitoring under conditions where other methods fail, taking advantage of the extremely high detection sensitivity that is typical of radiotracer applications.

Molecular imaging to guide systemic cancer therapy: Illustrative examples of PET imaging cancer biomarkers

Molecular imaging agents have the ability to non-invasively visualize, characterize, and quantify the molecular biology of disease. Recent advances in nuclear probe development, particularly in PET radiotracers, have generated many new imaging agents with precise molecular targets. With such specificity, PET probes may be utilized as biomarkers to objectively interrogate and evaluate pathology. Whereas the current indications for PET imaging are predominately confined to staging and restaging of malignancy, the utility of PET greatly expands when utilized as a biomarker, the topic of this review. As an imaging biomarker, PET may be used to (1) measure target expression to select subsets of patients who would most benefit from targeted therapy; (2) measure early treatment response to predict therapeutic efficacy; and (3) relate tumor response to survival. This review will discuss the application of radiotracers to targeted cancer therapy. Particular attention is given to new radiotracers evaluated in recently completed clinical trials and those with current or potential clinical utility. The diverse roles of PET in clinical trails for drug development are also examined.

Radiotracer application for characterization of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC

Abstract Radio isotopic tracer technique as one of the versatile nondestructive technique is employed to evaluate the performance of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC. The evaluation was made on the basis of ion-isotopic exchange reaction kinetics by using 131I and 82Br radioactive tracer isotopes. It was observed that for both the resins, the values of specific reaction rate (min−1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction under identical experimental conditions of 30.0 °C, 1.000 g of ion exchange resins and 0.001 mol/L labeled iodide ion solution, the values of specific reaction rate (min−1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.377, 0.212, 0.080 and 15.5 respectively for Dowex SBR LC resin, which was higher than 0.215, 0.144, 0.031 and 14.1 respectively as that obtained for Tulsion A23 resins. Also at a constant temperature of 30.0 °C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 84.75 % to 90.20 % for Dowex SBR LC resins which was higher than increases from 57.66 % to 62.38 % obtained for Tulsion A23 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions.

PET Tracers To Study Clinically Relevant Hepatic Transporters.

Transporter proteins expressed on the cell membranes of hepatocytes are directly involved in the hepatic clearance, mediating the transport of drugs and metabolites through the hepatocyte, from the bloodstream into the bile. Reduction of hepatic transporter activity (due to chemical inhibition, genetic polymorphism, or low expression) can increase systemic or liver exposure to potentially toxic compounds, causing adverse effects. Many clinically used drugs have been associated with inhibition of hepatic transporters in vitro, suggesting the potential involvement of liver transporters in drug-drug interactions (DDIs). Recently, radiolabeled hepatic transporter substrates have been successfully employed in positron emission tomography (PET) imaging to demonstrate inhibition of clinically relevant hepatic transporters. The present article briefly describes the clinical relevance of hepatic transporters followed by a review of the application of PET imaging for the determination of pharmacokinetic parameters useful to describe the transporter activity and the design, accessibility, and preclinical and clinical applications of available radiotracers. Finally, based on the analysis of the strengths and limitations of the available tracers, some criteria for the development of novel PET probes for hepatic transporters and new potential applications are suggested.

Diversity of RGD radiotracers in monitoring antiangiogenesis of flavopiridol and paclitaxel in ovarian cancer xenograft-bearing mice

IntroductionAlthough encouraging results had been shown in antiangiogenesis therapy monitoring, the underlying mechanism of RGD radiotracer accumulation needs to be further illustrated. This study was aimed to investigate the diversity of RGD radiotracers in monitoring antiangiogenic agent's effects and the underlying mechanism in ovarian cancer-bearing mice with a new agent flavopiridol compared with paclitaxel. MethodsOvarian cancer SKOV-3 xenograft-bearing mice were established and divided into three groups, flavopiridol, paclitaxel and control. Flavopiridol (5mg/kg body weight) and paclitaxel (20mg/kg body weight) were administered every 3days for 16days. Tumor growth and proliferation were monitored by caliper measurements and immunofluorescence staining. Antiangiogenic effects were determined by tumor microvessel density (MVD) in vivo and by endothelial cell tube formation assay in vitro, respectively. 99mTc-3P-RGD2 was prepared, and its biodistribution studies were carried out. The effect of antiangiogenesis therapy on integrin αvβ3 expression was studied by immunohistochemical staining and flow cytometry. ResultsBoth paclitaxel and flavopiridol therapy could apparently inhibit tumor growth and proliferation, and antiangiogenic effects of therapy were validated in vivo and in vitro. However, compared with the control group, ID%/g tumor uptake of 99mTc-3P-RGD2 showed a significant decrease at 2hours (by 39.96%±8.23%, P=0.044) and at 4hours (by 35.76%±11.42%, P=0.024) post injection in the paclitaxel-treated group, but a slight increase of tumor uptake in the flavopiridol-treated group at 2hours (by 4.42%±0.24%, p=0.898) and at 4hours (by 12.2%±1.84%, P=0.702). The further studies indicated flavopiridol therapy has a dual-effect, reducing integrin αvβ3 expression on endothelial cells due to the reduction of tumor MVD and up-regulating the integrin αvβ3 expression on tumor cells. ConclusionsThere is diversity in evaluating antiangiogenic response when using 99mTc-3P-RGD2, which may be an important reminder in future clinical applications of RGD radiotracers as a strategy for antiangiogenesis therapy response monitoring.

ARCEBS-2014: a platform for nuclear and accelerator scientists

The Third International Conference on Application of RadiotraCers and Energetic Beams in Sciences (ARCEBS14), was held at FFort Raichak, Kolkata during January 12–18, 2014. The Saha Institute of Nuclear Physics (SINP), a pioneering research institute of India, organized the conference. ARCEBS series of conferences crossed the subject boundaries from its inception and is a perfect blend of Physics, Chemistry, Biology, Environmental Sciences and other interdisciplinary research areas like radioactive ion beam, superheavy elements, etc. A national level discussion meeting on the ‘‘Application of Radiotracers in Chemical, Environmental and Biological Sciences (ARCEBS)’’ was held at the Saha Institute of Nuclear Physics in May 2004. The overwhelming response of that meeting encouraged the organizing committee to hold an international conference on the same theme to build a common platform to discuss the cross boundary research. The first and second international conferences (ARCEBS-06 and ARCEBS-10), organized by SINP in 2006 and 2010, were highly successful by the participation of large number of scientists from 27 countries all over the globe. However, to accommodate wider field of research in nuclear sciences the definition of ARCEBS was changed keeping the popular acronym and logo same. Therefore the third international conference of ARCEBS was named as Application of RadiotraCers and Energetic Beams in Sciences. The scientific programme of ARCEBS-14 was broadbased. All aspects of application of radiotracers and energetic beams were presented in the conference. This has been reflected in this special issue of Journal of Radioanalytical and Nuclear Chemistry (JRNC).

Development of RGD-Based Radiotracers for Tumor Imaging and Therapy: Translating from Bench to Bedside

The cell adhesion molecule integrin αvβ3 is an important player in the process of angiogenesis. In the last decades, a series of radiolabeled Arg-Gly-Asp (RGD) peptides targeting integrin αvβ3 has been prepared and optimized for positron emission tomography (PET) and single-photon-emission computed tomography (SPECT) imaging of integrin αvβ3 expression. Several promising radiotracers have been tested in clinical trials. In this review, we will introduce strategies that have been used to optimize and accelerate RGD radiotracers towards clinical translation; illustrate RGD-based radiotracers that have been investigated in clinical trials; and discuss the other applications of RGD radiotracers aside from tumor detection.

Soil Inositol Phosphate Biochemistry: A Call to Link Radiotracer Applications with Spectroscopic Structural Analysis

Early work on the use of mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy for the structural analysis of soil inositol phosphates and the use of radioisotope tracers to identify and measure soil inositol phosphate transformations is briefly described. Modern advances in the application of MS and NMR to the identification and quantification of soil inositol phosphate stereoisomers including advances in on‐line liquid chromatography (LC) coupled to MS and NMR in hyphenated LC–MS–NMR techniques are reviewed. Automated techniques used to measure 3H, 14C, 33P, and 32P with on‐line LC–NMR and LC–MS are described. Recommendations are made for the use of radioisotope‐labeled myo‐, D‐chiro‐, scyllo‐, and neo‐inositol and their phosphorylated forms in conjunction with the application of modern MS and NMR spectroscopic structural analysis in studies on inositol phosphate transformations in soils.

Performance Based Characterization of Nuclear and Non-Nuclear Grade Anion Exchange Resins Indion 102 and Indion-860 by Application of Radio Analytical Technique

Performance Based Characterization of Nuclear and Non-Nuclear Grade Anion Exchange Resins Indion 102 and Indion-860 by Application of Radio Analytical Technique The present study deals with the application of 131 I and 82 Br radioactive tracer isotopes to evaluate the performance of Indion-102 (nuclear grade) and Indion-860 (non-nuclear grade) ion exchange resins. The major parameters studied for evaluation were specific reaction rate (min-1 ), percentage and amount of ions exchanged (mmol). It was observed that for both the resins under identical experimental conditions, iodide ions exchange take place at faster rate as compared to that of bromide ions which was related to the extent of solvation. It was observed that at a constant temperature of 35.0 °C, as the concentration of spiked iodide ion solution increases 0.001 M to 0.004 M, the percentage of iodide ions exchanged increases from 63.8% to 68.8% for Indion-102 resins; while for Indion-860 resins it increases from 51.1% to 52.6%. Similarly for 0.002 M spiked iodide ion solution, with rise in temperature from 30.0 °C to 45.0 °C, it is observed that the percentage of iodide ions exchanged decreases from 66.1% to 64.0% using Indion-102 resins; while for Indion-860 resins it decreases from 52.4% to 49.8%. The study reveals that for both the resins there exist a strong linear correlation between amount of ions exchanged and concentration of ionic solution, as well as between amount of ions exchanged and temperature of exchanging medium. In general based on radiotracer applications it was observed that Indion-102 resins show superior performance than Indion-860 resins under identical operational parameters.

Development of Gold Nanoparticle Radiotracers for Investigating Multiphase System in Process Industries

This paper describes the development of colloidal Au-SiO2 with core-shell structure nanoparticle radioactive tracers by neutron activation in nuclear reactor that produce Au-198 (T1/2=2.7 d) emitting gamma ray of 412 keV. Using conventional citrate-reduction method, gold nanoparticles were prepared from its corresponding metal salts in aqueous solution then coated with uniform shells of amorphous silica via a sol-gel reaction. The citrate-reduction-based method provides gold nanoparticles with higher concentration and narrow size distribution. By using transmission electron microscopy (TEM), the resultant of particle size and silica coatings could be varied from tens to several hundred of nanometers by controlling the catalyzer and precipitation time. Au-SiO2 core-shell nanostructure is good to prevent the particles from getting agglomerated resulting in a big mass. In addition, silica surface offer very good chances that make the hydrophobic and hydrophilic behavior on the gold nanoparticles. EDXRF spectrum has proven that Au-SiO2 core-shell nanoparticles sample consists purely of a gold and silica particles. This target material of radiotracer application used to investigate multiphase system in process industries without disturbing the system operation.

Development of a 68Ge/68Ga Generator to Avail 68Ga in Organic Medium for Industrial Radiotracer Applications

A chromatographic 68Ge/68Ga generator using nano zirconia as the sorbent matrix was developed to avail 68Ga in an organic medium for industrial radiotracer applications. Acetylacetone was used as the eluent for the extractive desorption of 68Ga ions from the sorbent phase. The effect of varying the amount of acetylacetone on 68Ga yield and achieving ideal experimental conditions were studied. The major advantage of this generator is its ability to deliver ready to use “industrial 68Ga tracer” with > 90% yield and high radionuclidic and radiochemical purity. The performance of the generator remained consistent on repeated elutions over a period of 1 year.

MO‐G‐BRB‐01: Rosalyn Yalow: Contributions and Legacy, a Memorial Session

Dr. Rosalyn Yalow was a brilliant physicist who co‐developed the technique of radioimmunoassay (RIA). This is a pioneering application of radiotracers in medicine that allows the measurements of the concentration of hundreds of pharmacologic and biologic substances in the blood and in other fluids of the human body. Dr. Yalow's vision has led to the application of radiolabeled antibodies for the quantitative measurement of antigens in vivo through the use of positron emission tomography in combination with tumor specific antibodies labeled with positron emitters. In this presentation, the potential of 124I‐labeled antibodies to target and estimate disease burden will be discussed along with the utility of this information for personalized therapeutic strategies with drugs, radiation and antibodies.Learning Objectives:1. Learn how the principals of radioimmunoassay could be adapted to in vivo radioimmuno diagnosis.2. Learn how antibodies labeled with positron emitting isotopes could provide quantitative information on the amount of antigen and therefore tumor cells with a cancer lesion.3. Learn how radiolabeled antibodies could be used for therapy planning.

Development of a 99Mo/99mTc generator using alumina microspheres for industrial radiotracer applications

A chromatographic (99)Mo/(99m)Tc generator for industrial applications has been developed using alumina microspheres synthesized through sol-gel process to obtain (99m)Tc in both aqueous and non-aqueous media. The sorbent was mesoporous, mechanically strong and possessed high surface area. (99m)Tc could be eluted from generator system using either acetone or 0.9% NaCl solution with appreciably high yields and high radiochemical as well as radionuclidic purity. The facile, versatile generator provides an efficient way to access (99m)Tc at industrial sites for radiotracer applications.

ARCEBS in brief

The second international conference on Application of Radiotracers in Chemical, Environmental and Biological Sciences (ARCEBS-10) was organized by the Saha Institute of Nuclear Physics (SINP) in cooperation with International Atomic Energy Agency (IAEA), and was held in the SINP premises during November 7–13, 2010 in Kolkata, India. From its very inception, ‘‘ARCEBS’’ series of conference attracted researchers from all over the globe from various disciplines of science with the common thread of radiotracers or energetic ion beams. The peer community considers ARCEBS series as platform for trans-disciplinary research and exchanging ideas, ARCEBS-10 is no exception from that. ARCEBS keeps an eye on the cutting edge developments of the world on accelerator based technologies and proposed large scale future facilities like EURISOL or FAIR. This is the reason we have included an article on FAIR written by Professor Bikash Sinha, a renowned high energy physicist. By incorporating this article we would like to give the message that future generation nuclear chemists have lot to play with these kinds of huge radioisotope production facilities starting from the target development to the application of exotic radionuclides for the beneficial use of mankind. The organization of a conference like ARCEBS-10 is a collective effort and charter of cooperation of many. It is our duty to acknowledge the people whose effort made the conference a grand success. Professor Tibor Braun, Editor-in-Chief of the Journal of Radioanalytical and Nuclear Chemistry (JRNC) readily agreed to publish ARCEBS proceedings in a special issue of JRNC. Professor A. Chatt is the Editor-in-charge for conference proceedings of JRNC. His support helped us a lot to bring out this issue. The man behind the excellent electronic submission platform of JRNC articles is Dr. Andras Schubert. All the articles were published in the fastest possible time in the ‘‘on line first’’ of JRNC due to the effort of Dr. Schubert. We express our sincere thanks to Professors Tibor Braun, A. Chatt and Andras Schubert. We are deeply indebted to Professor Milan K. Sanyal, Director, SINP, for his generous financial help to organize the conference and his encouragement and suggestions in every step of the conference. We are grateful to Dr. R. K. Bhandari, Director, Variable Energy Cyclotron Centre (VECC), for his cooperation towards organizing the conference both in the form of financial help and other logistic supports. We thankfully acknowledge the encouragement received from Professor Bikash Sinha, Chairman, International Advisory Committee of ARCEBS-10 and Ex-Director of SINP and VECC. Professor Sinha is always a source of inspiration to us. S. Lahiri (&) Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India e-mail: susanta.lahiri@saha.ac.in

Quantitative Molecular Imaging of Neuronal Nicotinic Acetylcholine Receptors in the Human Brain with A-85380 Radiotracers

Neuronal nicotinic acetylcholine receptors (nAChRs) have been implicated in a spectrum of cognitive functions as well as psychiatric and neurodegenerative disorders, including tobacco addiction and Alzheimer's Disease. The examination of neuronal nAChRs in living humans is a relatively new field. Researchers have developed brain-imaging radiotracers for nAChRs, with radiolabeled A-85380 compounds having the most widespread use. We provide a brief background on nAChRs, followed by a discussion of the development and application of A-85380 radiotracers in human imaging studies. We describe potential future studies using nicotinic receptor radioligands for the study of tobacco addiction, including the mechanism of action of the smoking-cessation therapy varenicline. Throughout this review, we focus on the significant potential that resides in the identification and quantification of nAChRs in the living human brain.

Cerenkov luminescence tomography for in vivo radiopharmaceutical imaging.

Cerenkov luminescence imaging (CLI) is a cost-effective molecular imaging tool for biomedical applications of radiotracers. The introduction of Cerenkov luminescence tomography (CLT) relative to planar CLI can be compared to the development of X-ray CT based on radiography. With CLT, quantitative and localized analysis of a radiopharmaceutical distribution becomes feasible. In this contribution, a feasibility study of in vivo radiopharmaceutical imaging in heterogeneous medium is presented. Coupled with a multimodal in vivo imaging system, this CLT reconstruction method allows precise anatomical registration of the positron probe in heterogeneous tissues and facilitates the more widespread application of radiotracers. Source distribution inside the small animal is obtained from CLT reconstruction. The experimental results demonstrated that CLT can be employed as an available in vivo tomographic imaging of charged particle emitters in a heterogeneous medium.