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At least 19 recordsLinked to original sources
PubMed1980

[Clinical value of scintigraphic tumor diagnosis by means of test substances with tumor affinity. 2. Gallium radioisotopes].

Deriving from the principle of direct tumor visualization and the beginnings of positive imaging of malignant tumors, radiotracers with tumor affinity are distinguished by those with tumor-specific and non-specific uptake. With special regard to the tumor-specific localization of thyroid carcinomas using radioiodine (131J) and of osteoplastic bone tumors or metastases using 99m-labelled phosphate compounds, the tumor scintigraphy results mainly with radiopharmaceuticals possessing tumors affinity, however not a tumor-specific uptake. On the basis of experimental and clinical results Gallium-67, one of these tumor-seeking agents, has become most important tumor scintigraphy. The diagnostic possibilities and limitations in using Gallium-67 for tumor imaging are derived from: 1) the non-specific uptake of Gallium-67, 2) the diagnosis accuracy and its reasons, and 3) the determinant factor of viability of tumor affecting the Gallium-67 accummulation.

Brain Neoplasms↗
PubMed2002

Ga-66 labeled somatostatin analogue DOTA-DPhe1-Tyr3-octreotide as a potential agent for positron emission tomography imaging and receptor mediated internal radiotherapy of somatostatin receptor positive tumors.

Radionuclide labeled somatostatin analogues selectively target somatostatin receptor (SSTR)-expressing tumors as a basis for diagnosis and treatment of these tumors. Recently, a DOTA-functionalized somatostatin analogue, DOTATOC (DOTA-DPhe1-Tyr3-octreotide) has been developed. This compound has been shown to be superior to the other somatostatin analogues as indicated by its uniquely high tumor-to-non-target tissue ratio. DOTATOC can be labeled with a variety of radiometals including gallium radioisotopes. Gallium-66 is a positron emitting radionuclide (T(1/2) =9.5 hr; beta+=56%), that can be produced in carrier free form by a low-beam energy cyclotron. In this study we investigated SSTR targeting characteristics of 66Ga-DOTATOC in AR42J rat pancreas tumor implanted nude mice as a potential agent for diagnosis and receptor-mediated internal radiotherapy of SSTR-expressing tumors. We compared our results with 67Ga- and 68Ga- labeled DOTATOC. The radiolabeling procedure gave labeling yield ranged from 85-95% and radiochemical and chemical purity was > 95%. In-vitro competitive binding curves and in-vivo competitive displacement studies with an excess of unlabeled peptide indicates that there is specific binding of the radioligand to SSTR. Animal biodistribution data and serial microPET images demonstrated rapid tumor uptake and rapid clearance from the blood and all tissues except kidney. Maximum % ID/g values for tumor were 10.0 +/- 0.7, 13.2 +/- 2.1 and 9.8 +/- 1.5 for 66Ga-, 67Ga-, and 68Ga-DOTATOC, respectively. Calculated tumor, kidney and bone marrow doses for 66Ga-DOTATOC based on biodistribution data were 178, 109 and 1.2 cGy/MBq, respectively. We conclude that 66Ga labeled DOTATOC can be used for PET diagnosis and quantitative imaging-based dosimetry of SSTR positive tumors. 66Ga-DOTATOC may also be used in higher doses for ablation of these tumors. However, kidney is the critical organ for toxicity (tumor/kidney ratio = 1.64), and high kidney uptake must be eliminated before devising a therapy protocol.

Animals↗
PubMedDate not supplied

Imaging techniques for myocardial inflammation.

Dilated cardiomyopathy (DC) represents a heterogeneous group of disorders which results in morbidity and mortality in young individuals. Recent evidence suggests that a subset of these patients have histologic evidence of myocarditis which is potentially treatable with immunosuppression. The identification of myocardial inflammation may therefore lead to development of therapeutic regimens designed to treat the cause rather than the effect of the myocardial disease. Ultimately, this may result in improvement in the abysmal prognosis of DC. The currently accepted technique for identification of active myocardial inflammation is endomyocardial biopsy. This technique is not perfect, however, since pathologic standards for the diagnosis of myocarditis have not been established. Furthermore, focal inflammation may give rise to sampling error. The inflammation-avid radioisotope gallium-67 citrate has been used as an adjunct to biopsy improving the yield of myocarditis from 7 percent to 36 percent. Serial imaging correlates well to biopsy results. Future studies are designed to study the applicability of lymphocyte labelling techniques to myocardial inflammatory disease.

Animals↗
PubMed1985

Sequential technetium-99m/gallium-67 scintigraphic evaluation of subclinical osteomyelitis complicating fracture nonunion.

Twenty-four patients with a history of post-traumatic fracture nonunion underwent sequential 99mTc and 67Ga citrate scintigraphy in an attempt to differentiate between posttraumatic fracture nonunion and nonunion complicated by subclinical osteomyelitis. Neither technetium nor gallium studies alone nor in combination, with or without clinical correlation, could help delineate between fracture nonunion and nonunion complicated by subclinical osteomyelitis because of the increased technetium and gallium radioisotope uptake associated with the nonunion site.

Adolescent↗
PubMed1977

Recent advances in cancer diagnosis with nuclear medicine techniques.

Recent progress in cancer detection in nuclear medicine has been significant and encouraging. Three main trends are responsible. First, techniques of imaging have improved, often in conjunction with the development of new and better imaging devices. Secondly, new radiopharmaceuticals are being investigated. Finally, interaction with other imaging modalities has started. In general, this yields complementary information further refining the diagnostic process.

Antibodies, Neoplasm↗
PubMed2007

68Ga-PET radiopharmacy: A generator-based alternative to 18F-radiopharmacy.

Positron emission tomography (PET) is becoming a dominating method in the field of molecular imaging. Most commonly used radionuclides are accelerator produced 11C and 18F. An alternative method to label biomolecules is the use of metallic positron emitters; among them 68Ga is the most promising as it can be produced from a generator system consisting of an inorganic or organic matrix immobilizing the parent radionuclide 68Ge. Germanium-68 has a long half-life of 271 days which allows the production of long-lived, potentially very cost-effective generator systems. A commercial generator from Obninsk, Russia, is available which uses TiO2 as an inorganic matrix to immobilize 68Ge in the oxidation state IV+. 68Ge(IV) is chemically sufficiently different to allow efficient separation from 68Ga(III). Ga3+ is redox-inert; its coordination chemistry is dominated by its hard acid character. A variety of mono- and bifunctional chelators were developed which allow immobilization of 68Ga3+ and convenient coupling to biomolecules. Especially peptides targeting G-protein coupled receptors overexpressed on human tumour cells have been studied preclinically and in patient studies showing high and specific tumour uptake and specific localization. 68Ga-radiopharmacy may indeed be an alternative to 18F-based radiopharmacy. Freeze-dried, kit-formulated precursors along with the generator may be provided, similar to the 99Mo/99mTc-based radiopharmacy, still the mainstay of nuclear medicine.

Chelating Agents↗
PubMed2006

New calculation of excitation functions of proton-induced reactions in some medical isotopes of Cu, Zn and Ga.

The new calculations on the excitation functions of 61Ni(p,n)61Cu, 62Ni(p,n)62Cu, 64Ni(p,n)64Cu, 63Cu(p,2n)62Zn, 63Cu(p,n)63Zn, 65Cu(p,n)65Zn, 66Zn(p,n)66Ga, 67Zn(p,2n)66Ga, 67Zn(p,n)67Ga and 68Zn(p,n)68Ga reactions have been carried out in the 5-30 MeV proton energy range. The calculations involve the cascade exciton model, preequilibrium nuclear reaction model and exciton model. The calculated results are compared with the experimental data taken from the literature.

Copper Radioisotopes↗
PubMed1997

PET-pharmacokinetics of 18F-octreotide: a comparison with 67Ga-DFO- and 86Y-DTPA-octreotide.

The quantitative uptake kinetics of (2-[18F]fluoropropionyl-(D)phe1)-octreotide (I), a somatostatin (SRIF) receptor-specific tracer, was measured by PET. Conventional organ biodistribution and in vivo stabilities of the tracer as well as in vivo displacement and SRIF receptor blocking were determined. The 18F-fluorinated octreotide was compared with ([67Ga]-DFO-B-succinyl-(D)phe1)-octreotide (II) and ([86Y]-DTPA-(D)phe1)-octreotide (III). Initially, 2-10 MBq of the labeled tracers were injected into male Lewis rats bearing an exocrine pancreatic islet cell tumor. PET measurements were performed dynamically between 0 and 120 min postinjection. Organ distributions were determined 5, 15, 30, 60, and 120 min postinjection. The extent of metabolic degradation was analyzed in serial blood and urine samples as well as in homogenized samples of tumor, liver, and kidney. The uptake of (I) by the tumor was rapid (maximum accumulation at 1-2 min postinjection) and high (about 0.5 +/- 0.2% ID/g), followed by a fast and continuous release with koff = 10 +/- 2. 10(-5) s-1. The tracer was found to remain intact in vivo up to 120 min postinjection. Specific binding of (I) to SRIF receptors in the adrenals, the pancreas, and the pituitary gland was demonstrated in vivo by pretreatment and displacement experiments. Compound (II) also showed a fast uptake by the tumor. Its tumor residence half-life was longer (koff = 3.0 +/- 0.5 . 10(-5) s-1). Compound (II) was also predominantly excreted intact. One hour postinjection, the remaining activity in the blood pool was found to be bound to serum proteins. Early uptake kinetics for compound (III) were also rapid but reached only half the tumor uptake of (II). Compared to (I), the release of 86Y-activity from the tumor was slower (koff = 3.1 +/- 1.3 . 10(-5) s-1). Compared to (II), compound (III) was considerably less stable in vivo. The main critical organs for (II) and (III) are kidneys and bones, whereas (I) is predominantly accumulated in the liver. The in vivo behavior of (I) closely resembles 14C-labeled octreotide. Thus, 18F-labeled octreotide may be of interest in the quantitation and investigation of in vivo properties of somatostatin receptors by PET. However, the short residence of (2-[18F]fluoropropionyl-(D)phe1)-octreotide in tumors and its hepatobiliary excretion may complicate the interpretation of abdominal tumors.

Animals↗
PubMed2001

The role of nuclear medicine in infection and inflammation.

Investigators have used various techniques and radionuclides such as 51Cr and 32P-diisofluorophosphate to label blood cells and to study cell survival. Early studies also used these radionuclides to label human leucocytes for cell survival by in-vitro counting. But external imaging could not be done with these agents. Starting with the use of the gamma-emitting radionuclide (111)In-oxine for in-vitro labelling of phagocytic leucocytes, external imaging became possible. This method was the basis of visualisation of cell distribution within the body. Because an abscess consists primarily of leucocytes, leucocytes labelled with (111)In localise within the abscess and are detectable by imaging. Nowadays other radiopharmaceuticals with other underlying uptake mechanisms are also used to detect inflammatory or infectious foci in patients. Nuclear medicine can be most useful in patients with fever of unknown origin, where a focus has to be defined, or in patients where a lesion is known by clinical symptoms or by a radiological imaging and the differentiation between infection and other pathologies has to be made.

Fever of Unknown Origin↗
PubMed1978

57Co-bleomycin imaging study of tumors of the head and neck.

57Co-Bleomycin (57Co-BLM) was used to visualize malignancies of the head and neck because it does not present the disadvantages of many other radiopharmaceuticals. In a series of 21 patients with 9 control subjects and 12 cases of tumors. 57Co-BLM showed a high and rapid uptake in primary site and metastases of malignant tumors of various histologic types, but not in benign tumors such as angiofibromas. Compared to 67Ga-citrate. 57Co-BLM has many advantages for tumor imaging in the areas of nose, pharynx and larynx: No background activity due to the concentration of 57Co-BLM in normal structures of the head and neck has ever been observed, as opposed to what happens with 67Ga-citrate. Furthermore, the blood clearance of 57Co-BLM is much more rapid than that of 67Ga-citrate, so that an early study may be performed in a 6-24 hr. interval instead of 48-72 hr. with 67Ga-citrate. 57Co-BLM scintigraphy is an easy, non-invasive and sensible diagnostic technique in determining the extent of malignant tumors in ORL patients.

Bleomycin↗
PubMed2000

Chronic infiltrative lung diseases: value of gadolinium-enhanced MRI in the evaluation of disease activity--early report.

STUDY OBJECTIVE: To determine the value of gadolinium-enhanced MRI in the assessment of disease activity in chronic infiltrative lung diseases (CILDs). DESIGN: Retrospective study. SETTING: University hospital. MATERIALS AND METHODS: Twenty-five consecutive patients with CILD were studied. The following diseases were diagnosed: sarcoidosis (n = 10), bronchiolitis obliterans organizing pneumonia (n = 3), usual interstitial pneumonia (n = 4), radiation pneumonia (n = 2), desquamative interstitial pneumonia (n = 1), rheumatoid lung (n = 1), vasculitis (n = 1), alveolar proteinosis (n = 1), bronchioloalveolar carcinoma (n = 1), and chronic eosinophilic pneumonia (n = 1). In each patient, the disease activity was assessed by one or more of the following studies: BAL (n = 18), gallium-radioisotope lung scanning (n = 6), serum angiotensin-converting enzyme assay (n = 10), and open lung biopsy (n = 4). T1-weighted breath-hold MRI studies were obtained before and after IV injection of gadolinium. The MRI examinations were analyzed to assess the presence or absence of lesional enhancement. RESULTS: The presence of enhanced pulmonary lesions was seen in 14 patients. All of these patients had active disease. Of the 17 patients with active disease, 14 had enhanced lesions, and 3 had unenhanced lesions. Pulmonary lesions were not enhanced in any patients with inactive disease. The difference was statistically significant (Fisher Exact Test, p < 0.05). CONCLUSION: Gadolinium-enhanced MRI may prove to be a useful tool in assessing disease activity in CILDs.

Adult↗
PubMed2003

A case report of primary hepatic squamous cell carcinoma that remarkably responded to low dose arterial injection of anti-cancer drugs.

Primary hepatic squamous cell carcinoma is rare. In this case, a malignant lesion was detected in bilateral hepatic lobes by ultrasound sonography and computed tomography. The maximum tumor diameter was approximately 10 cm. Tumor tissue obtained by aspiration liver biopsy was diagnosed as poorly differentiated squamous cell carcinoma. In gallium radioisotope scanning, no focus was detected in any organs other than the liver. As therapy, anti-cancer drugs were administered via hepatic arterial infusion. The patient received 10 mg of cis-diaminedichloroplatinum (CDDP) and 250 mg of 5-fluorouracil (5-FU) for 5 days every week. The therapy was continued for 3 weeks, and the same doses of CDDP and 5-FU were given to the patient once per 2 weeks in the clinic. The intrahepatic tumor lesion began to decrease from the start of treatment, and had almost disappeared 8 months after. Recurrence of the liver tumor occurred at 12 months from the start of treatment. The patient was re-admitted and treated with the same anti-cancer drugs via hepatic arterial injection. However, the drugs showed remarkable effect no longer and she died in month 23. The treatment with chemotherapy via hepatic arterial injection for a patient with squamous cell carcinoma offered a favorable therapeutic effect.

Aged↗
PubMed1994

Imaging of abdominal inflammation using other radioisotope techniques.

99mTc-HMPAO-labelled white cell scanning is compared with other radionuclide techniques in this contribution. The sensitivity and specificity using both 111In and 99mTc-HMPAO-labelled leucocytes are comparably high. Both imaging methods are therefore suitable for imaging inflammation. However, images are available more quickly using 99mTc-HMPAO; their quality is superior and the radiation dose is lower. 111In is beneficial for chronic infections. 67Ga citrate is less specific for inflammation, since it also localizes in tumours, but it is useful in chronic infection. 99mTc nanocolloid has not been found suitable for imaging abdominal inflammation, but more so for bone and joint diseases. Comparisons of 99mTc-HMPAO leucocytes with 123I-labelled monoclonal antibodies show poorer results using the monoclonal antibody because of non-specific binding to plasma proteins. Visualization of lesions is generally poorer using 99mTC-HIG than 99mTc-HMPAO leucocytes and is less sensitive and specific. Few reports using 99mTc-labelled monoclonal antibodies are available. Early results are promising and more specific antibodies may be available in the future. Synthetic chemotactic peptides offer a novel approach to the detection of infection. However, at present the recommended method for imaging acute abdominal inflammation is 99mTc-HMPAO leucocytes.

Abdomen↗