18-Fluoride labeled sodium fluoride positron emission tomography with computer tomography: the impact of pretreatment staging in intermediate- and high-risk prostate cancer.

Background: 18-Fluoride labeled sodium fluoride (Na-18-F) positron emission tomography with computer tomography (PET/CT) has a better sensitivity and specificity than whole body bone scan (WBBS) in detecting osseous metastatic prostate cancer. We performed a pilot study of 20 men to examine what level of impact Na-18-F PET/CT has on management plans when used for staging newly diagnosed prostate cancer.

Materials And Methods: Twenty men were prospectively enrolled into the study in South Australia.

Hybrid Tc-magnetite tracer for dual modality sentinel lymph node mapping.

Accuracy of sentinel lymph node identification using radioactive tracers in non-superficial cancers can be limited by radiation shine through and low spatial resolution of detection systems such as intraoperative gamma probes. By utilising a dual radioactive/magnetic tracer, sensitive lymphoscintigraphy can be paired with high spatial resolution intraoperative magnetometer probes to improve the accuracy of sentinel node detection in cancers with complex multidirectional lymphatic drainage. Dextran-coated magnetite nanoparticles (33 nm mean hydrodynamic diameter) were labelled with Tc and applied as a lymphotropic tracer in small and large animal models.

Preparation of Ga-Mg-Ca-phytate colloid and its evaluation as a liver imaging agent.

The objective of this study was to investigate the radiosynthesis of Ga-Mg-Ca-phytate colloid and then characterise the formulation for radiochemical purity (RCP), radioactive particle size distribution, and biodistribution in normal rats. This radiocolloid was prepared by mixing an aqueous solution of phytic acid, Ga ions, a dispersant, Mg and Ca ions, and then heating the contents at 100°C for 5 minutes. After cooling the vial to 5°C, the solution was basified to pH 5 and stored in the cold.

Ga-Ca-phytate particles: A potential lung perfusion agent of synthetic origin prepared in a cold kit format.

The objective of this study was to investigate the radiosynthesis of Ga-Ca-phytate particles and then characterize the formulation for radiochemical purity, radioactive particle size distribution, and biodistribution in normal rats. This radiotracer was prepared using a commercial phytate cold kit after reconstitution with saline, Ga-chloride generator eluent, calcium chloride, and air, then heating at 100°C for 30 minutes to achieve 99% radiochemical purity of Ga-particles that were 21% 3-5 μm, 8% 5-15 μm, and 71% >15 μm in diameter. This optimal formulation was stable for 2 hours at room temperature.

A study of radiogallium aqueous chemistry: in vitro and in vivo characterisation of (67) Ga-hydrolysed-stannous fluoride particles.

The objective of this study was to explore the aqueous chemistry of gallium using (67) Ga-chloride starting material, by radiolabelling hydrolysed(h)-stannous fluoride particles and then characterising the optimal formulation for radiochemical purity (RCP) and radioactive particle size distribution in vitro. The pilot reactions determined stannous fluoride was added to (67) Ga-acetate under nitrogen and then heated at 100 °C for 20 min to achieve ≥95% RCP and (67) Ga-particles were >3 µm in diameter. A high radioactive concentration of (67) Ga-h-SnF2 particles could be prepared similarly in ≥97% RCP with 74% as 3-5 µm and 26% >5 µm in diameter.

An improved assay for (68)Ga-hydroxide in (68)Ga-DOTATATE formulations intended for neuroendocrine tumour imaging.

The objective of this study was to identify a more rapid assay for (68)Ga(OH)3 impurity in (68)Ga-DOTATATE formulations. Three methods were used to prepare (68)Ga(OH)3 reference material (pharmacopoeial, bench titration and automated radiosynthesis), and four quality control methods for its assessment (thin layer chromatography, membrane filtration, HPLC and solid phase extraction). The optimal method of preparing (68)Ga(OH)3 was by titrating (68)Ga(3+) with buffered sodium hydroxide solutions to pH 5.

Radiotracers used for the scintigraphic detection of infection and inflammation.

Over the last forty years, a small group of commercial radiopharmaceuticals have found their way into routine medical use, for the diagnostic imaging of patients with infection or inflammation. These molecular radiotracers usually participate in the immune response to an antigen, by tagging leukocytes or other molecules/cells that are endogenous to the process. Currently there is an advancing effort by researchers in the preclinical domain to design and develop new agents for this application.

Lymphoscintigraphy is more effective using higher specific activity (99m)Tc-antimony trisulfide colloid in the rat.

Technetium-99m-antimony trisulfide colloid ((99m)Tc-ATC) was investigated with varying specific activity in the rat lymphatic system, as well as its binding to rat blood cells in vitro. Low, moderate and high doses of (99m)Tc-ATC were subdermally injected into tails of rats (n=3) and 30min later whole body lymphoscintigraphic images were acquired. (99m)Tc-ATC was incubated for 30min at 37°C with whole blood (n=4) as for control, at 4°C as for hypothermia, as opsonized at 37°C and lipopolysaccharide (LPS) at 37°C.

Postchemotherapy and tumor-selective targeting with the La-specific DAB4 monoclonal antibody relates to apoptotic cell clearance.

Unlabelled: Early identification of tumor responses to treatment is crucial for devising more effective and safer cancer treatments. No widely applicable, noninvasive method currently exists for specifically detecting tumor cell death after cytotoxic treatment and thus for predicting treatment outcomes.

Methods: We have further characterized the targeting of the murine monoclonal antibody DAB4 specifically to dead tumor cells in vitro, in vivo, and in clinical samples.

Host immune response determines visceral hyperalgesia in a rat model of post-inflammatory irritable bowel syndrome.

Background: Irritable bowel syndrome (IBS) is associated with visceral hyperalgesia and frequently occurs after a transient gastrointestinal infection. Only a proportion of patients with acute gastroenteritis develop post-infectious IBS suggesting differences in host response to inflammatory stimuli. We aimed to investigate this concept by characterizing visceral sensitivity in two rat strains, following a chemically induced colitis.

APOMAB, a La-specific monoclonal antibody, detects the apoptotic tumor response to life-prolonging and DNA-damaging chemotherapy.

Background: Antineoplastic therapy may impair the survival of malignant cells to produce cell death. Consequently, direct measurement of tumor cell death in vivo is a highly desirable component of therapy response monitoring. We have previously shown that APOMAB representing the DAB4 clone of a La/SSB-specific murine monoclonal autoantibody is a malignant cell-death ligand, which accumulates preferentially in tumors in an antigen-specific and dose-dependent manner after DNA-damaging chemotherapy.

Lymphatic mapping with 99mTc-Evans Blue dye in sheep.

Objective: 99mTc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully discriminate the sentinel lymph node. The aim of this study was to investigate the potential of 99mTc-EB as an agent to map the lymphatic system in an ovine model.

Colonic transit studies with 99mTc-rhenium sulfide colloid in live rats. A preliminary study.

Abnormal colonic motility is associated with clinical relevant conditions such as irritable bowel syndrome or constipation. Accurate assessment of colonic transit in an animal model would be useful in studying these conditions and screen potential drug candidates. The aim of this study was to assess if scintigraphic analyses could reliably evaluate total and segmental colonic transit as a measure of colonic motility of a non-absorbable radiotracer in rats.

How regenerating lymphatics function: lessons from lizard tails.

Rational treatment of lymphoedema may be improved in the future with a better understanding of the physiological processes involved in the regeneration of new lymphatic vessels (lymphangiogenesis). Many lizard species undergo tail autotomy as a predator escape response and subsequently regenerate nonlymphoedematous tails. Such species may offer novel models for examining lymphangiogenesis.

Scintigraphic imaging of experimental colitis with technetium-99m-infliximab in the rat.

The radiolabeled monoclonal antibody (99m)Tc-infliximab was assessed as an inflammation imaging agent in a rat colitis model in comparison with (99m)Tc-tin colloid-labeled-leucocytes. (99m)Tc-infliximab and (99m)Tc-tin fluoride colloid-labeled-leucocytes were administered to (n>3) rats previously exposed to 2,4,6-trinitrobenzenesulfonic acid by rectal instillation. Whole body scintigraphic images were acquired and physiological organ assays were performed to obtain quantitative data.

The tissue distribution of Evans blue dye in a sheep model of sentinel node biopsy.

Background: Tc-Evans blue is a 'single dose' agent for lymphatic mapping combining radioactivity and blue dye for sentinel node identification. The mechanism and distribution of blue dye retention in the lymph node is not clearly understood.

Objective: To demonstrate the cellular distribution of Tc-Evans blue in sheep sentinel lymph nodes by measuring the radioactivity of different tissue components and correlating this with pathological examination.

99mTc-Evans blue dye for mapping contiguous lymph node sequences and discriminating the sentinel lymph node in an ovine model.

Background: The aim of this study was to investigate the potential of (99m)Tc-Evans blue for discriminating the sentinel lymph node in multitiered lymph node sequences by using an ovine model. (99m)Tc-Evans blue is an agent that has both radioactive and color signals in a single dose. Previous studies in smaller animal models suggested that this agent could have advantages over the dual-injection technique of radiocolloid/blue dye.

An improved (99m)Tc-aprotinin kit formulation: quality control analysis of radiotracer stability and cold kit shelf life.

(99m)Tc-aprotinin scintigraphy has been demonstrated to be a useful noninvasive imaging technique for amyloid deposits located in extraabdominal regions of patients. The aim of this study was to develop an improved aprotinin cold kit formulation, to validate the kit for long-term stability, as well as to assess the radiotracer stability by novel quality control methods. The aprotinin cold kit formulation of Trasylol, pyrophosphate (PYP)-chelated stannous reductant and an alkaline buffer, was dispensed into nitrogen-filled vials and aliquots frozen at -20 degrees C.

Radiolabelling and biodistribution of 111In-antimony trisulphide colloid.

The aim of this study was to prepare 111In-antimony trisulphide colloid (111In-ATC) and evaluate its chemical properties in comparison with 99mTc-ATC. After reconstitution of an antimony trisulphide cold Kit with 111In-chloride, 111In-ATC was formed with >95% radiochemical purity in the presence of neutralising phosphate buffer. The product was found to be stable for 4.

Characterization and quality control analysis of 99mTc-bicisate.

The aim of this study was to investigate the mini cartridge versus paper chromatography quality control methods for determining the radiochemical purity (RCP) of (99m)Tc-bicisate. The 4 methods that were compared with the manufacturer's method included Whatman 17 paper/ethyl acetate solvent, instant thin-layer chromatography (ITLC) silica gel paper/saline solvent, reverse-phase C18 mini cartridge/saline solvent, and strong anion exchange mini cartridge/water solvent. At 30 min after reconstitution, (99m)Tc-bicisate was formed at 97%-98% RCP as assayed by the paper and cartridge methods, and the strong anion exchange/water for injection (WFI) system slightly underestimated the percentage at 96%.

Pharmacokinetics and normal scintigraphic appearance of 99mTc aprotinin.

Objective: To confirm the pharmacokinetics and biodistribution of 99mTc aprotinin in normal volunteers and to determine the optimum time for scanning post-injection, prior to further investigations of 99mTc aprotinin as an imaging agent for amyloidosis.

Methods: Five patients (three men and two women, average age 49 years, age range 38-66 years) without a history of amyloidosis or any of the associated diseases, were included in this prospective study. Blood and urine were collected and images were performed of the whole body and wrists.

Use of [14C]-sodium bicarbonate/urea to measure physical activity induced increases in total energy expenditure in free-living healthy males.

The aim of this study was to evaluate the utility of the [(14)C]-sodium bicarbonate/urea technique to detect physical activity-induced increases in total energy expenditure in free-living healthy men. Thirteen healthy males aged 34.1 +/- 11.

Understanding the radiolabelling mechanism of 99mTc-antimony sulphide colloid.

The chemistry of antimony trisulphide colloid (ATC) was examined to elucidate the radiolabelling mechanism with 99mTcO4(-). Ion exchange chromatography and atomic absorption spectrophotometry techniques determined ATC to be resistant to hydrolysis in 0.1M hydrochloric acid (HCl) at 25 degrees C or 100 degrees C (>97% recovery, Sb3+ absent).

Comparison of 99mTc-alafosfalin and 67Ga-citrate in a mouse model of bacterial infection.

Background: The antibiotic-peptide (99m)Tc-alafosfalin was assessed as an infection imaging agent in Staphylococcus aureas infected mice by comparison with (99m)Ga-citrate, and also examined for influence of septic status on tracer biodistribution by comparison with normal mice.

Material And Methods: Intramuscular doses of S. aureus were administered into the right thigh muscle of mice and the infection was allowed to develop for 20 hours.

Effect of port composition on tumor cell adherence: an in vivo model.

Introduction: We have reported previously on an in vitro model to examine tumor cell adherence to metal and plastic laparoscopic ports and to port sites through which they had been passed. This demonstrated that increased numbers of tumor cells were found both on metal ports compared with plastic ports and on the port sites through which metal ports had passed. In this study, the in vivo adherence of such cells to ports and port sites was investigated.