Abstract

IJNM

Indian Journal of Nuclear Medicine

0972-3919

Society of Nuclear Medicine, India

ijnm-19-4-session-005

Session V

122004

194141147

Radioiodination of Plumbagin and its Evaluation as an Anti Tumor Agent

Bapat

Ketaki

Pandey

Usha

Samuel

Grace

Venkatesh

Meera

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai -400 085

Ref. No: 32 KB RP H13

AbstractObjectives

Plumbagin, isolated from the plant Plumbago rosea is reported to have anti-cancerous property. In order to evaluate the potential of iodinated plumbagin for tumor therapy, plumbagin was radioiodinated with ¹²⁵I and evaluated in tumor bearing mice.

Methods

Plumbagin was iodinated using chloramine T as the oxidising agent. In brief, plumbagin (10-20 mg in methanol) was added to 50 ml of 0.5 M phosphate buffer (pH 7.5). 74 MBq Na¹²⁵I was added followed by chloramine-T (10 ml, 20 mg). After 5 min, the reaction was terminated by addition of sodium metabisulphite (20 ml/100 mg).% Yield was determined by paper electrophoresis 30 cm Whatman 1 paper (0.025 M phosphate buffer, 10V/cm, 60 min). Purification of ¹²⁵I-plumbagin was carried out by preparative TLC using toluene: acetic acid (99:1) as the developing solvent system. The product was characterised by HPLC using gradient elution (water/acetonitrile with 0.1% trifluracetic acid). Biodistribution studies were carried out in Swiss mice bearing fibrosarcoma. The animals were sacrificed at 3h and 24 h post injection and% radioactivity associated with tumor and other organs was determined.

Results

Radioiodination yield was ~35-40%. In the standardized TLC system, Rf, of ¹²⁵I-plumbagin was 0.5-0.6 while R_f^of¹²⁵I- was 0. The radiochemical purity of ¹²⁵I-plumbagin was - 95%. In the HPLC system, ¹²⁵I-plumbagin had a retention time (R_t) of 14 minutes while I^- has an R_t of 4 minutes. The product was stable (>90% radiochemical purity) for 15 days at 4 °C. In the biodistribution studies, the compound exhibited a tumor uptake of ~2% ID/gm at 3 h post injection which reduced to ~0.8% ID/ gram at 24 h post injection. After 24 h, ~4% ID/ gm radioactivity was observed in kidneys while ~5% and 10% ID/gm was retained in stomach and liver respectively. In vivo deiodination was not observed as seen from absence of thyroid associated activity showing the in-vivo stability showing of the product.

Conclusions

Plumbagin was successfully labeled with ¹²⁵I using chloramine T method. Purity of the labelled product was established by HPLC and paper electrophoresis method. ¹²⁵I-plumbagin exhibited significant tumor uptake in Swiss mice bearing fibrosarcoma. Further studies would be carried out using cancer lines of human origin.

Key words¹²⁵I-plumbaginanti tumorfibrosarcoma

^99mTc (Co)₃-HTIDA: Synthesis, Radiolabeling and Biodistribution

Satpati

Drishty

Bapat

Ketaki

Banerjee

Sharmila

Kothari

Kanchan

Samuel

Grace

Venkatesh

Meera

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai -400 085

Ref. No: 33 DS RP H14

AbstractObjectives

Serotonin (5-hydroxytryptamine, 5-HT) is a widely distributed neurotransmitter present in the central nervous system. Studying serotonin receptors in the brain is of interest because of altered serotonergic transmission in many neurological and psychological diseases like Alzheimer's disease, schizophrenia, anxiety and depression. Thus, to develop a radioligand for diagnosis of such disorders, iminodiacetic acid (IDA) derivative of 5-HT has been synthesized. 5-HT-IDA derivative was radiolabeled with [^99mTc (CO)₃ (H2O)₃]⁺ synthon which is known to form complexes with high specific activity and specificity.

Methods

In atypical procedure of radiolabeling, 250mg of 5-HT-IDA derivative was dissolved in 0.1 mL of methanol and was added to 0.4ml of [^99mTc(CO)₃(H2O)₃]⁺ synthon (pH 4.5). The reaction was carried out at 70°C for 20 minutes. The labeled complex was characterized by C-18 reverse phase HPLC in gradient mode with water and acetonitrile as solvent. Biodistribution studies were carried out in normal Swiss mice at 5 min, 30 min, 3 h post injection.

Results

The complex, ^9mTc (CO)₃-HTIDA, eluted out as a single species having retention time of 8 minutes with radiolabeling yield of >95%. Partition coefficient log P was found to be 0.7 as determined by distribution in octanol and saline. Histidine and cysteine challenge studies were carried out and the complex was found to be stable as shown by no change in retention time in HPLC chromatogram. At 5 min p.i, brain uptake was found to be 0.5% ID/g which reduced to 0.1% after 30min. The complex washed out completely from brain after 3 h and was cleared through renal route.

Conclusions

The brain uptake observed with the ^99mTc (CO)₃-HTIDA was low but it was found to have successfully crossed the blood brain barrier. A slight structural modification may lead to a better product. In-vitro studies to determine specific uptake of the complex in receptor-rich areas of brain are in progress.

Key wordsSerotonin^99mTc-carbonyl

A Novel [^99mTcºN]⁺² Complex of Metronidazole Xanthate as a Potential Agent for Targeting Hypoxia

Mallia

Madhava B

Mathur

Anupam

Subramanian

Suresh

Banerjee

Sharmila

Sarma

H.D.

Venkatesh

Meera

Radiopharmaceuticals Division, Bhabha Atomic Research CentreMedical and Biological Products Program, Board of Radiation and Isotope Technology, Bhabha Atomic Research Centre, MumbaiRadiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai

Ref. No: 34MMRPH15

AbstractObjective

To evaluate the potential of metronidazole xanthate labeled via, stable, easy to prepare, [^99mTcºN]⁺²core, as a tumor hypoxia-imaging agent.

Methods

The metronidazole xanthate was synthesized by reacting calculated amount metronidazole with carbon disulphide in dimethoxy ethane in presence of crushed sodium hydroxide. The reaction was carried out overnight at room temperature. A yellow precipitate formed was filtered, washed with dimethoxyethane and dried. The product was characterized by GC-MS, ¹³C-NMR and by elemental analysis. The ^99mTc-nitrido core was prepared from pertechnetate using commercially available nitrido kit. The protocol for the preparation of nitrido intermediate involved vortexing 1 ml of freshly eluted pertechnetate in kit vial and incubating it for 20 minutes. The nitrido intermediate was formed in >98% yield and was characterized by TLC and HPLC. Under optimized condition, the complexation was carried out by mixing 0.5 ml of freshly prepared ^99mTc-nitrido intermediate to 0.5 ml of saline containing 1 mg of the ligand and incubating it at room temperature for 30 minutes. The complexation was carried out by mixing freshly prepared ^99mTc-nitrido core and ligand and incubating at room temperature for 30 minutes. The complex was characterized by C-18 reverse phase HPLC, using acetonitrile: water as the mobile phase, and by paper electrophoresis. The biodistribution studies were carried out in Swiss mice bearing fibrosarcoma tumor.

Results

Metronidazole xanthate was synthesized in moderate yield. The ligand formed a neutral complex with [^99mTcN]²⁺core in >95% yield with a low ligand concentration of 1 mg/ml [~3 x 10-³ M]. The biodistribution studies carried out in Swiss mice bearing fibrosarcoma tumor showed selective accumulation of the injected activity in the tumor (1.44 ± 0.26% per gram 1hr p.i.) with major clearance through hepatobiliary route. The complex showed high tumor/muscle ratio (2.15 and 3.35 at 1 hr and 3 hr post-injection respectively) and tumor/blood ratios were comparable to agents ^99mTc-BMS181321 and9^9mTc-BRU59-21 agents reported earlier for imaging hypoxia.

Conclusions

Metronidazole xanthate was synthesized and labeled with novel [^99mTcN]²⁺core with high specific activity. Biodistribution studies showed considerable retention of activity in solid tumor indicating promise towards its development as a hypoxia-imaging agent.

Key wordsMetronidazoleTechnetium NitridoTumorHypoxia

^99mTc N-Complexes of t-Butyl Dithiocarbamate (TBDTC) and Methoxyisobutyl Dithiocarbamate (MIBDTC) as Myocardial and Brain Imaging Agents

Mathur

Anupam

Mallia

Madhava B

Subramanian

Suresh

Banerjee

Sharmila

Kothari

Dhotare

Bhaskar

Sarma

H.D.

Venkatesh

Meera

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai - 400085Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai - 400085Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai - 400085Medical and Biological Products Program, Board of Radiation and Isotope Technology, Mumbai - 400094

Ref. No: 35AMRPH16

AbstractObjective

To evaluate the potential of neutral, lipophilic complexes of t-butyl dithiocarbamate and methoxyisobutyl dithiocarbamate, with novel [^99mTcN]⁺² core, as myocardial and brain imaging agents.

Methods

The dithiocarbamate ligands were synthesized from respective amines viz. t-butylamine and methoxyisobutylamine by reacting with carbondisulphide in dry ether in presence of crushed sodium hydroxide. 2-methoxyisobutylamine was synthesized from 2-hydroxyisobutyronitrile by a two-step process involving O-methylation in excess dry methanol in presence of anhydrous ZnCl₂, followed by reduction using Lithium aluminium hydride in dry ether. The ligands were characterized by elemental analysis. The [^99mTcN]⁺² intermediate was prepared from pertechnetate using commercially available nitrido kit. The complexation was carried-out by mixing freshly prepared ^99mTc-nitrido intermediate and ligand and incubating at room temperature for 10 min. The complex was characterized by C18 reverse phase HPLC, using acetonitrile:water as the mobile phase, and by paper electrophoresis. The biodistribution studies were carried-out in normal Swiss mice.

Results

The ligands were synthesized in near quantitative yields. They were radiolabeled in excellent yields (>95%) with novel ^99mTc-nitrido core, forming [^99mTcNL₂] type complexes with high specific activity. Both the complexes were found to be neutral by paper electrophoresis. HPLC elution pattern of the complexes showed that they were formed as a single species with retention time of 4.5±0.2 min and 4.1±0.1 min for ^99mTcN-t-butyl dithiocarbamate and ^99mTcN-methoxyisobutyl dithiocarbamate respectively. Both the complexes showed myocardial as well as brain uptake. ^99mTcN-t-butyl dithiocarbamate complex showed high brain uptake (3.74 %ID/ g) at 10 min p.i. with brain/blood ratios higher than that of the standard agent ^99mTc-d,l-HMPAO at all time points studied. This complex also showed better heart/blood and heart/lung ratio when compared to ^99mTcN-(NOEt)₂ up to 30 min p.i.. ^99mTcN-methoxyisobutyl dithiocarbamate showed myocardial uptake of 6.41%ID/gat5 min p.i., which decreased to 1.76%ID/g60 min p.i.. ^99mTcN-methoxyisobutyl dithiocarbamate also exhibits good brain uptake but relatively fast washout was observed from both brain and heart when compared to ^99mTcN-t-butyl dithiocarbamate.

Conclusions

Two dithiocarbamate ligands, structural analogues of well known myocardial agents, methoxyisobutyl isonitrile (MIBI) and t-butyl isonitrile (TBI), were synthesized and labeled via [^99mTcN]²⁺ core to give high specific activity complexes. Biodistribution studies were carried out in Swiss mice. Both the complexes showed myocardial and brain uptake. The results obtained for ^99mTcN-t-butyl dithiocarbamate shows good promise towards the development as a potential brain-imaging agent.

Key wordsBrain imagingmyocardial imaging^99mTc-nitrido coreMIBITBI

Development of ^99mTc-Labeled Recombinant Antibody - Radiopharmaceutical Agent for Tumor Imaging in Breast Cancer.

Chaudhari

Pradip

Singh

Ravibhusan

Sawant

Urmila

Rajan

MGR

Bandyopadhyay

Dilip

Division of Laboratory medicine, Tata Memorial Centre, Mumbai-400 12.Laboratory Nuclear Medicine Section, Bhabha Atomic Research Center, Tata Memorial Centre, Mumbai - 400 012.

Ref. No: 36PCRPH17

AbstractObjectives

Target specific radiopharmaceutical agents with high resolution imaging, high tumor to background ratios, minimal or no immunogenecity are required for the diagnosis and targeted therapy in cancers. Monoclonal antibodies (MAb) with suitable properties have been envisaged for immunoscintigraphy for clinical diagnosis in nuclear medicine practice. In these applications, ^99mTc has almost replaced other radionuclides due to its nuclear properties and its availability from a generator.

Methods

The recent generation recombinant antibody molecules called single chain fragments of variable heavy and light chain (ScFv) are superior over the conventional monoclonal antibody for tumor targeting because of their smaller size. We have used the recently developed breast cancer specific targeting molecules for preparing the radio-immuno-pharmaceutical agent with ^99mTechnetium. The aim of work is to study the labeling efficiency of different ScFv derivatives and fusion proteins with 99mTc and study their biodistribution in Balb/c mouse.

Results

We have been able to establish the labeling protocol for binding ^99mTc to scFv, the labeling efficiency was obtained over 97% and purification through gel filtration yielded high purity labeled antibody. Biodistribution study with this labeled molecule at 15,30,60 and 120 min post injection was found to be increasing in liver to maximum 23% at 120hrs and decreasing in blood (maximum 4.2% at 15 min). The thyroid uptake was found to be negligible.

Conclusions

Potential for further evaluation

KeywordsRadiolabeled antibodyRecombinant antibody

Pharmacoscintigraphic Evaluation of Polysorbate80 Coated Chitosan Nanoparticles for Brain Targeting

Soni

Sheetal

Babbar

Anil Kumar

Sharma

Rakesh Kumar

Banerjee

Tanima

Maitra

Amarnath

Division of Radiopharmaceuticals and Radiation Biology, Institute of Nuclear Medicine and Allied Sciences, Brig. S K Mazumdar Road, Delhi - 110 054, IndiaDepartment of Chemistry, University of Delhi, Delhi - 110 007, India

Ref. No: 37 SB RP H18

AbstractObjectives

The blood-brain barrier (BBB) represents an insurmountable obstacle for delivery of drugs to brain. BBB acts as anatomical barrier formed by tight junctions of capillaries within the brain and thus regulates the passage of substances between peripheral circulation and the central nervous system (CNS). An approach to overcome this barrier has been drug delivery to brain using appropriately modified nanoparticles. Nanometer sized particles have easy accessibility in the body and can be transported to different body sites through systemic circulation of blood. A major limitation to the use of nanoparticulate systems is the non-specific uptake of injected carriers by RES especially by macrophages in the liver and spleen resulting in the rapid clearance from blood. An alternative to significantly alter the biodistribution and pharmacokinetics of nanoparticles is to coat the nanoparticles with hydrophilic surfactants.

Methods

Thus, chitosan nanoparticles, because of enhanced circulation time and decreased uptake by reticuloendothelial cells, were evaluated for efficient brain delivery. Since polysorbate80 is known to facilitate brain uptake by endothelial cells, polysorbate80 (1%w/w) coated crosslinked chitosan nanoparticles (10% crosslinking with glutraldehyde) of size less than 100nm were prepared in the aqueous core of the reverse micelles. After radiolabeling using ^99mTc, the in vivo brain uptake profiles in strain 'A’ mice were studied. Gamma scintigraphic technique was also employed to study the uptake of uptake of radiolabeled nanoparticles in brain.

Results

The studies revealed that the radiocomplex was stable up to five hours with labeling efficiency ~80-85%. The concentration of radiolabeled chitosan nanoparticles in brain was increased to nearly five folds when coated with polysorbate80 (1%w/w) as compared to the radiolabeled uncoated chitosan nanoparticles. At a critical concentration of polysorbate80 (1%w/w) the translocation of nanoparticles from blood to brain was maximum. These results were further supported by gamma scintigrams of New Zealand rabbits which showed that administration of radiolabeled chitosan nanoparticles when coated with polysorbate80 (1%w/w) has a greater uptake by brain tissue as compared to uncoated chitosan nanoparticles.

Conclusions

Thus nanoparticles can be exploited to deliver drugs to the brain efficiently provided the particles are long circulating in blood and are able to cross the BBB.

Key wordsPharmacoscintigraphyNanoparticlesBrain Delivery

Production of Iodine-125 from Natural Xenon Gas for Radioimmunoassay (RIA) and Therapeutic Applications

Joshi

P. V.

Sane

Surekha

Bapat

Ketaki

Manolkar

R. B.

Shivarudrappa

Radiopharmaceticals Division, Bhabha Atomic Research Centre, Mumbai-400 085

Ref. No: 38VSRCH19

AbstractObjectives

Standardization and regular indigenous production and radiochemical processing of ¹²⁵I from neutron activation of natural xenon targets and its suitability for nuclear medicine applications.

Methods

Natural xenon target was irradiated in Dhruva reactor and radiochemically processed to separate ¹²⁵I and purify ¹²⁵I-NaI formed. A specially designed Al capsule was fabricated to hold target under pressure and to meet all the quality assurance tests for irradiation of gaseous targets in the reactor. Two Al capsules containing of 4g each of xenon gas at 10 was irradiated for 2 weeks at a flux of 1.8 x 10¹³n/cm²/sec. After cooling period of 40 days to allow the decay of ¹²⁶I (T_1/2is 13 days and a â^-, ã emitter), the target was processed by a wet chemical process in a shielded plant. Radionuclidic purity of ¹²⁵I was checked by gamma ray spectrometry and radiochemical purity by paper electrophoresis.

Results

About 37 GBq (1 Ci) of ¹²⁵I-NaI was obtained per batch. RNP of ¹²⁵I produced was 99% with ¹²⁶I contents within limits (~1%). About 80% recovery of ¹²⁵I as NaI was obtained with the final product having a radioactive concentration of about 40mCi/ml. The quality of product was found to be suitable for the preparation of a tracer for RIA application and for the preparation of brachy therapy sources for therapy.

Conclusions

A method for the indigenous production & radiochemical processing of Ci level of ¹²⁵I-NaI by neutron irradiation of natural xenon target has been standardized. The quality and the suitability of the product for its use as a tracer in RIA application and for the preparation of brachy therapy sources have been established.

Key words¹²⁵I-NaI RadiochemicalProductionNuclear Medicine

Studies on the Preparation of High Specific Activity Iodine-131 for Radionuclide Therapy by Dry Distillation from Neutron Irradiated TeO₂

Ambade

R.N.

Vimalnath

K.V.

Chirayil

Viju

Shinde

S.N.

Shivarudrappa

Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai-400 085.

Ref. No: 39 VC RC H20 Non Member

AbstractObjectives

To study the feasibility to develop a method for the production of high specific activity Iodine-131 required for the preparation of therapeutic capsules by dry distillation of neutron irradiated TeO₂ target.

Methods

TeO₂ targets(2-5g) were irradiated in Dhruva reactor for 7 days at a neutron flux of ~4 x 10¹³ n.cm-2.s-¹ to produce ¹³¹I activity in the range of 1.85-3.7 GBq (50-100 mCi). Radioactive ¹³¹I was separated by dry distillation in a quartz assembly at ~720°C using oxygen carrier gas. The liberated ¹³¹I activity was trapped in a mixture of NaOH and Na2S03 solution. ¹³¹I-NaI formed was characterized by high resolution gamma ray spectrometry and paper electrophoresis.

Results

About 50% of the ¹³¹I initially present was recovered in the final product. The recovery of ¹³¹I-NaI was observed to be dependent on the neutron flux, amount of the target (i.e. the amount of ¹³¹I formed in the target), distillation temperature, carrier gas flow rate, concentration of the absorber solution etc. Radionuclide purity of ¹³¹I produced was found to be greater than 99% and the radiochemical purity was more than 95%. The quality of ¹³¹I-NaI produced was comparable to that of a standard sample. On extrapolation, it was calculated that about 555-740GBq (15-20Ci) of ¹³¹I-NaI could be produced in a batch on irradiation of 100g of TeO₂ target for 3 weeks having required radioactive concentration suitable for the preparation of ¹³¹I-NaI therapeutic capsules.

Conclusions

Studies on the production of Iodine-131 with high specific activity and high radioactive concentration by dry distillation of neutron irradiated TeO₂ target were carried out. On scaling up of the process, it is possible to produce ¹³¹I-NaI with a radioactive concentration of about 37-74GBq/ml which would enable the preparation of ¹³¹I-NaI capsules for therapeutic applications, which is currently not available to nuclear medicine centres in India.

Key wordsIodine-131Dry distillationRadionuclide Therapy

The Sensitivity and Specificity of ^99mTc-Ciprofloxacin (Diagnobact) Scanning in Picking up Bacterial Infection in Patients with Diabetic Foot.

Singh

Baljinder

Parsad

Nidhi*Singh

*BhattacharyaParmar

AshokMittal

Department of Nuclear, PGIMER, Chandigarh-160 012

Division of Radiopharmacy, INMAS, Delhi.

Ref. No: 40 BS RP H21

AbstractObjectives

To evaluate the sensitivity and specificity of ^99mTc-Diagnobact to pick the active bacterial infection/s in diabetic foot condition

Methods

In the present study, 25 diabetic patients (4F: 21M, mean age: 55.1 ± 12.45 years) with clinical suspicion of bacterial infection in the foot were enrolled for the study. A written consent was taken from all patients including approval from institute ethical committee. All these patients underwent 3-phase ^99mTc-MDP bone scanning (flow phase, blood pool and 4h delayed imaging) and ^99mTc-Diagnobact (procured from INMAS, Delhi) imaging at 1h, 4h & 24h under the dual headed Siemens Gamma camera. Only the patients with gradually rising lesion to background ratio till 24 hrs were taken as positive for active bacterial infection on ^99mTc-Dignobact scanning. Microbiological examination (gold standard) of the sample from each foot lesion was also carried out in each patient.

Results

^99mTc-Ciprofloxacin scan was positive in 13, negative in 12 patients including 6 with superficial ulcers. Bacterial culture was positive in 18 subjects, negative in 7 including 1 with osteomyelitis on bone biopsy only. Therefore ^99mTc-Ciprofloxacin scan was 'true positive' in 12, 'true negative' in 6, false positive in 1 and false negative in 6. Sensitivity and specificity of the test was 67.7% and 87.7% respectively

Conclusions

It is concluded that this infection-imaging agent in the form of single vial kit preparation (Diagnobact) has a good diagnostic as well as prognostic applications in bony microbial infections. Although, this technique has been reported earlier, this is the first study on the use of indigenously developed single vial kit preparation of ^99mTc-ciprofloxacin in the diagnosis of infective diabetic osteomyelitis.

Key words^99mTc-ciprofloxacinDiabetic Foot3-phase ^99mTc -MDP Bone Scanning

A Simple Technique of ^99mTc Labeling of Leucocytes with SnF2Colloid for Imaging Infection

Sinha

Ghosh

Ganguly

Sarkar

B.R.

Bhowmick

Gupta

Mitra

Das

M.K.

Chattopadhyay

Chatterjee

Debnath

Regional Radiation Medicine Centre (VECC), Kolkata Board of Radiation & Isotope Technology, Kolkata IICB, Kolkata

Ref. No: 41SS RC H22

AbstractObjectives

Radionuclide scanning is probably the most useful imaging technique for visualizing the sites of active inflammation or infection. Amongst the large number of radiopharmaceuticals used for scintigraphy of infection or inflammation, WBC labeled with Tc-99m is widely used and is highly sensitive and specific. Unfortunately, the conventional method of Tc-99m labeling of WBC (with HMPAO) requires a large quantity of blood with prolonged handling, and difficult cell separation procedures. The idea of this paper is to present a short rapid and effective method for radio labeling of WBCs, which does not need cell separation, and the WBCs labeled by this method were found to be good enough for locating the sites of infection.

Methods

For this purpose, we have used a modification of the technique of Hirsch et al., where WBC in whole blood are exposed to Tc-99m labeled SnF2 colloid. The colloid particles are engulfed by phagocytic WBCs, which thus became Tc-99m labeled spontaneously.

Initially, SnF2 colloid was prepared in distilled water andTc-99m pertechnetate (5 -10 milli Curies) in saline was added. Quality control chromatography of the Tc-99m labeled SnF2 colloid was done, and labeling efficiency was found to be 85% to 95%. This Tc-99m labeled SnF2 colloid was added in vitro to a blood sample (Around 10 ml.) of the patient was shaken and centrifuged. It was found that activity was restricted to the buffy coat. The supernatant serum was aspirated and discarded, and the packed cell volume was repeatedly washed with saline to remove free colloid, and aggregated colloid. Following washing, the volume was reconstituted with normal saline, and thoroughly mixed. The entire reconstituted solution was injected intravenously into the patient for locating the site of inflammation.

This technique was first tried in 2 no. of experimental rabbits for identifying the site of inflammation induced by previous injection of turpentine. Imaging was performed at four hours after radiopharmaceutical administration. It was found that in each animal, the labeled WBCs concentrated at the site of inflammation, exhibiting a high target-to-nontarget ratio.

Results

Subsequently, 4 patients suffering from various chronic inflammatory diseases underwent imaging with this radiopharmaceutical. The labeled WBCs were seen to concentrate at the site of the lesion in 3 cases.

Conclusions

It was concluded that this method for Tc-99m labeling of WBCs using SnF2 colloid is much simpler and quicker than that using HMPAO and yet achieves a high labeling efficiency. The leucocytes labeled by this method can be used effectively for imaging infection.

The Use of Dipyridamole Stress Myocardial Perfusion Scans as a Prognostic Indicator, in Patients Undergoing Renal Transplantation.

Nath

S.D. Satish

Masood

Mohamed

Shihab.Al.Muhanadi

Biswas

Salman

Hani

Nampoory

M.R.

Nuclear Medicine Dept, Organ Transplant Centre, Ibn Sina Hospital, Kuwait

Ref. No: 42 SN NC B4

AbstractObjectives

There is a high likelihood of coronary artery disease in patients with end stage renal failure because they are known to be diabetic and hypertensive. It is important to know how far these patients will be able to withstand cardiac surgery without any complication. In these circumstances we need a test which could identify high risk patients who need to undergo revascularization before transplantation.

Methods

We used dipyridamole pharmacological stress in all patients since all of them were weak and unable to walk on a treadmill. Single photon computerized tomography (SPECT) images were acquired by gamma camera. Tetrofosmin stress rest protocol was used. Mean age of patients was 51.24 (SD +/ - 9.10). There were 32 male and 7 female patients. 39 patients had chronic renal failure, 34 were hypertensive, 4 patients had a prior history of myocardial infarction and 22 patients were diabetics.

Results

Six patients, who had abnormal myocardial perfusion scans, also had angiographic positive lesions. Two patients had normal myocardial perfusion scan with significant coronary artery disease. All the 39 patients underwent renal transplant, 6 patients with positive angiograms had revascularization prior to transplant. Out of 33 patients who had normal scans 31 patients had no cardiac events for 1 yr after transplant.

Conclusions

This data indicates that patients with diabetes and ESRD who are at high risk of cardiovascular events can be identified. Sensitivity and specificity of this test is 78% and 100%. Dipyridamole stress myocardial perfusion scan is an ideal test for risk stratification in chronic renal failure, who have intermediate clinical probability for coronary artery disease with poor functional capacity (<4mets). Patients with stable chest pain syndrome and normal stress SPECT images have very low risk of death or non fatal MI even in this subgroup with high likelihood of coronary artery disease.

Key wordsDipyridamole Pharmacological StressCoronary Artery DiseaseTetrofosmin

Improvement of Myocardial Perfusion Status in Response to Indian Vedic Breathing

Anand

YNI

Muthu

The Nucleus, No 3, "I" Block, Kuvempunagar, Mysore - 570 023Tata Main Hospital, Jamshedpur, Jharkhand, India

Ref. No: 43YNNCB1

AbstractIntroduction

Yoga is the buzz word all over the world today. Amidst their busy schedule, people tend to ignore their personal health. Management of various disorders, especially those involving interventions, surgical or radiological, is very expensive. The Indian Vedic Exercises, of which Pranaayaama is one, emphasize on prevention of the diseases in order to keep the individual in good health. It is equally applicable to those who have already suffered from various disorders and in whom both improvement and/or avoidance of further deterioration are required. However, no objective assessment of the disease status in response to these exercises has been reported so far.

Objectives

This study was undertaken on patients with reversible myocardial perfusion defects to objectively monitor the improvements in the myocardial perfusion in response to a breathing exercise, Pranayama, a breathing technique prescribed in the Indian Vedic Sciences.

Methods

Two patients who were found to have reversible myocardial perfusion defects were taken up in this study. These defects were diagnosed from the myocardial perfusion SPECT done in stressed (on TreadMill) and resting states with 99m Technetium labeled MIBI. These patients were taught the pranayama technique which is done for about 30 minutes every day. At the end of four months from the commencement of this technique, the myocardial perfusion SPECT studies were repeated. Details of the exercise in the form of a CD are available on request.

Results

Overall good improvements were observed in all the quantitative parameters in the TMT and SPECT studies in the studies done after the pranayama procedures in both the patients. Perfusion defects seen in the stress images of the initial studies have almost completely reversed in the stress images of the later study. Patients are asymptomatic and are leading a comfortable life.

Conclusions

This is only a data on two cases that has objectively evaluated the effects of pranayama and its effects on myocardial perfusion. Since the results were encouraging, we recruited twenty more volunteers to gather data on a large number of patients. Some of the details will be presented in the next paper to be presented by Mr G S Muthu. We conclude that, this exercise, since inexpensive and has no adverse effects, should be tried on a large number of patients, who are otherwise unfit or unwilling for any interventional procedures, and on those who are willing to do this exercise.

Key wordsVedic breathingMycardial Perfusion scanMPI

Partial Volume Correction for Positron Emission Tomography Based on Hot Sphere/ Warm Background Phantoms

Srinivas

Shyam M.

Dhurairaj

Thiruvenkatasamy

Surti

Suleman

Alavi

Abass

Hospital of the University of Pennsylvania, Philadelphia, PA 19104, U.S.A.

Ref. No: 44 SS IN F1

AbstractObjectives

The aim of this research is to establish a method for correction of the "partial volume effect", which is observed in Positron Emission Tomography (PET) because of spatial resolution limitations of scanners. The effect manifests itself by radioactive counts from a source or focus "spilling out" into a region that is volumetrically larger in the reconstructed image than its physical size. This has been extensively studied in the past and models for recovery of counts based on phantoms with hot spheres in a cold background have been developed. The goal of this study is to establish similar models of recovery for a situation that is closer to human imaging environment, namely hot spheres/ lesions in a warm background.

Methods

A NEMA image quality torso phantom with six small spheres (diameters of 1,1.3, 1.7, 2.2, 2.8, and 3.7 cm) was filled with water with a uniform activity (18-F 2-Fluorodeoxyglucose, FDG) concentration. The activity concentration ratio for the six spheres with respect to the background was 8:1, 6:1, and 4:1 for three different image acquisitions on our Philips Allegro scanner. The maximum Standardized Uptake Value (SUV) for each hot sphere was collected along with the average SUV of the background for calculation of recovery coefficients.

Results

The recovery coefficient (RC) for each sphere was calculated using a formula, which attempts to restore the contrast ratio to the expected value (accounting for the "spill out" of radioactivity and also subtracting out "spill in" of radioactivity that may occur in a warm background). The "spill in" phenomenon is quite significant especially in low contrast lesions of small physical size. RCs ranged from 80% to 11% producing characteristic logarithmic curves for each phantom when they were plotted versus diameter of the spheres. These curves also demonstrated that RCs are strongly dependent on the size of the lesion and only a weak function of the contrast ratio between the sphere and the background.

Conclusions

Using hot spheres in a warm background most closely resembles the imaging situation in a human, where there is never truly a cold background. These RC curves may be utilized for a more accurate measurement of SUV which could help in the early diagnosis of a pulmonary nodule or other small lesion. This method could facilitate generation of equipment specific recovery coefficients for partial volume correction in PET imaging.

Key wordsPositron Emission Tomography (PET)Partial Volume EffectRecovery Coefficient (RC)