Ga-67 Citrate Research Articles

Nuclear medicine and esophageal surgery.

The principal radionuclide procedures involved in the evaluation of esophageal disorders that are amenable to surgery are illustrated and briefly described. The role of the radionuclide esophagogram (RE) in the diagnosis and management of achalasia, oculopharyngeal muscular dystrophy and its complications, tracheoesophageal fistulae, pharyngeal and esophageal diverticulae, gastric transposition, and fundoplication is discussed. Detection of columnar-lined esophagus by Tc-99m pertechnetate imaging and of esophageal carcinoma by Ga-67 citrate and Tc-99m glucoheptonate studies also is presented.

Subacute Splenic Abscess

A case of a 23-year-old man with an encapsulated, anaerobic splenic abscess is reported. Both the In-111 leukocyte and Tc-99m sulfur colloid scans demonstrated an intrasplenic defect. The Ga-67 citrate scan revealed uptake in the rim of the abscess only where the abscess cavity was relatively photon-deficient. The combined Tc-99m sulfur colloid/In-111 leukocyte/Ga-67 scan appearance of a subacute splenic abscess has not been described previously. In cases suspected to be splenic abscesses the combined In-111 leukocyte/Tc-99m sulfur colloid imaging is the most useful.

Comparative studies of radiocitrates in oncological models—I. 99mTc citrate and 67Ga citrate uptake by EMT-6 tumors in mice

67Ga citrate and 99mTc citrate (Solcocitran) were injected sequentially, with an interval of 48 h, into Balb/c mice bearing transplanted EMT-6 tumors. Tissue distributions of 67Ga and 99mTe were measured simultaneously at intervals of 1, 3, 5 and 8 h after injection of the 99mTc citrate (49, 51, 53 and 56 h after 67Ga citrate). Maximal tumor:blood ratios for 99mGa and 99mTc were 13.8 ± 3.2 and 4.0 ± 1.0 respectively, both occurring at the final period. The maximum tumor index (T.I. = T:B x % dose/g) for 67Ga was 71 ± 23% 56 h after injection, and for Tc was 13 ± 12% 1 h after injection. Liver, kidney and spleen had equal or higher concentrations of radioactivity than tumor for either radiotracer. The somewhat higher tumor:blood ratio for 67Ga citrate was offset by the time required for this optimum to be reached. Alternatively, the best 99mTc citrate tumor:blood ratios were attained within 8 h, with less liver and gut radioactivity. These data fall within the range of results from other clinical and animal model studies of 67Ga citrate and Tc citrate. In view of the radiation dose, the inconvenience of the 48–72 h wait, and the cost of 67Ga, and because neither radiopharmaceutical is tumor specific, 99mTc citrate may have a place in early oncological screening. The results are discussed as part of a comprehensive review of the 99mTc citrate literature.

頭頸部領域の<SUP>67</SUP>Ga-citrateの正常集積分布縁の定量的解析と,その臨床的応用への研究

頭頸部領域の<SUP>67</SUP>Ga-citrateの正常集積分布縁の定量的解析と,その臨床的応用への研究

Gallium-67 Citrate Scintigraphy in Pulmonary Embolism

Eight cases of pulmonary embolism were evaluated with Ga-67 citrate scintigraphy. Of the eight patients, all but one showed evidence of abnormal Ga-67 citrate localization within involved regions of the lung as demonstrated by ventilation-perfusion lung scintigraphy. The sole patient who did not demonstrate Ga-67 localization within the lung had marked breast accumulation of the radiotracer which may have obscured lung parenchymal uptake. Since Ga-67 citrate is known to accumulate within inflammatory lung processes, this radiotracer would not have a specific role in differentiating pulmonary embolism from these conditions. This study disagrees with the results of other studies in the medical literature that describe such a role.

Absence of Gallium-67 Avidity in Diffuse Pulmonary Calcification

Diffuse pulmonary uptake by bone-seeking radiopharmaceuticals has been reported previously but, in the same patient, would pulmonary uptake of Ga-67 citrate yield clinically meaningful results? A patient with hypercalcemia and renal failure in whom bone scintigraphy demonstrated striking diffuse bilateral pulmonary uptake, but subsequent gallium imaging demonstrated no evidence of pulmonary uptake greater than body background, is discussed. We conclude that pulmonary uptake of gallium cannot be attributed to calcium deposition and should carry the same clinical significance in regard to inflammatory and malignant lesions as would be assigned to patients without pulmonary calcific deposits.

Dual radionuclide subtraction imaging of the spleen

Dual radionuclide subtraction imaging of the spleen using 67Ga citrate and 99mTc is useful in further delineating lesions that are identified on either a routine radiogallium survey or on a conventional sulfur colloid liver-spleen image. Better anatomic localization of left subphrenic abscesses may be obtained. Differentiation of tumors and abscesses from less serious lesions such as cysts, infarcts, and hematomas is possible. We have found this technique to be generally applicable to any organ that can be selectively imaged using a technetium radiopharmaceutical, including the liver, bones, and kidneys. In addition, we are currently evaluating thallium-pertechnetate subtraction imaging in the evaluation of parathyroid adenomata.

Thyroid localization of Ga-67 citrate

Thyroid localization of Ga-67 citrate

Placenta, embryo, and tumor uptake of 67Ga-citrate and 59Fe-citrate.

The uptake of gallium citrate Ga67 and ferrous citrate Fe59 was studied in pregnant rats with or without a 4-dimethylamino-stilben(DS)-induced sarcoma tumor. The liver and placenta of the mother concentrated 67Ga, while the uptake of 67Ga in the embryo was minimal. However, the embryo showed higher concentrations of 59Fe. Preloading with iron did not affect the 67Ga uptake of the placenta, but increased the uptake in the blood and liver of the mother. With regard to 59Fe uptake, iron loading only affected the embryo liver. Tumors and the placenta showed a similar 67Ga uptake but a different incorporation of 59Fe. The probable mechanisms involved are discussed.

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.

Imaging of Soft Tissue Tumors with Tc(V)-99m Dimercaptosuccinic Acid

Tumor scintigraphy, using Tc(V)-99m dimercaptosuccinic acid (Tc(V)-DMS) was performed in 58 patients with soft tissue tumors, and the results were compared with that of Ga-67 citrate. Tc(V)-DMS was found to have a sensitivity of 90% for malignant tumors including aggressive fibromatosis compared to that of Ga-67 citrate, which was 56%. However, the specificity of Tc(V)-DMS for these tumors was 71% but with Ga-67 citrate the specificity was 80%. The imaging accuracy in soft tissue tumors with Tc(V)-DMS and Ga-67 citrate was 78% and 71%, respectively. Although the accumulation of Tc(V)-DMS has been detected in some benign soft tissue tumors, the reduced accumulation in inflammatory lesions compared to Ga-67 citrate was recognized, and Tc(V)-DMS could be of great use in the detection of extension or location of malignant soft tissue tumors.

Gallium Scintigraphy in Bronchogenic Carcinoma: The Effect of Tumor Location on Sensitivity and Specificity

Fifty-one patients with primary lung cancer were evaluated using 67Ga citrate scintigraphy with respect to detection of peripheral primary, hilar metastasis, and mediastinal metastasis. The results demonstrated the necessity for an understanding of the criteria used in considering the gallium scintigram as either positive or negative, as well as the instrumentation employed in performing the test before any meaningful sensitivity and specificity figures can be derived within a given institution. Only with this understanding can actual strategy for instituting invasive procedures be achieved.

Relation between 67Ga uptake and iron metabolism in rat tissues.

The relationship between 67Ga uptake and iron metabolism was investigated in rat tissues. 67Ga and 59Fe(II) both accumulated in the mitochondrial-lysosomal fraction after being injected. Moreover, they both showed especially high affinity for heparan sulfate (HS) among various acid mucopolysaccharides (AMPS). When iron (ferrous citrate) was injected IV before, simultaneously with, and after 67Ga citrate IV injection, 67Ga uptake was significantly inhibited in normal rat liver in all cases. Elevated 67Ga uptake in the liver of CCl4-treated rats was also lowered to the control level by iron pretreatment. High zinc intake remarkably elevated the 67Ga uptake in rat liver. The contents of iron in the liver and liver AMPS of 0.75% zinc-fed rats were lowered in comparison with those in controls. Thus, the elevation of 67Ga uptake in the liver of zinc-fed rats might be due to the decrease of iron bound to HS.

Malignant external otitis: the role of computed tomography and radionuclides in evaluation.

Nine patients with malignant external otitis (MEO) were evaluated with Tc-99m bone scans, Ga-67 citrate scans, pluridirectional tomography, and computed tomographic (CT) scans in order to assess the role of each in the diagnosis and management of MEO. The Tc-99m and Ga-67 citrate scans were the most accurate studies in the initial identification of disease activity, while the return to normal or improvement of the Ga-67 citrate scan has been shown to correlate best with clinical resolution of MEO. CT demonstrated soft-tissue disease and central skull base osteomyelitis better than pluridirectional tomography. CT is excellent for localizing and following the progression of bone disease; however, because reossification of the skull base is a very slow process, CT cannot be used to follow accurately regression or inactivity of MEO affecting this area. CT is the best modality for following soft-tissue extension of MEO.

The role of Tc-99m MDP and Ga-67 citrate in predicting the cure of osteomyelitis.

Twenty rabbits with chronic osteomyelitis of the tibia were treated for eight weeks and then scanned with Tc-99m MDP and Ga-67 citrate. All were sacrificed and bacteriologic cultures of the tibia were obtained. All rabbits had positive Tc-99m MDP scans at the end of treatment despite thirteen cures of osteomyelitis. Eight had negative gallium scans and negative cultures. Five of the twelve positive gallium scans had negative cultures, while seven had positive cultures. Tc-99m MDP alone is not sensitive enough to be useful in predicting the cure of osteomyelitis, and combining Tc-99m MDP and Ga-67 citrate scintigrams offers no additional information over the Ga-67 citrate scintigram alone in follow-up of osteomyelitis.

A comparison of Tc-99m colloid labeled leukocytes and Ga-67 citrate for the disclosure of sepsis.

A comparison of Tc-99m colloid labeled leukocytes and Ga-67 citrate for the disclosure of sepsis.

Difficulty of diagnosing infected hypertrophic pseudarthrosis by radionuclide imaging.

Hypertrophic pseudarthrosis was studied with Tc-99m MDP and Ga-67 citrate in 11 patients. Two of the 11 pseudarthroses were complicated by infection. A high concentration of both radiopharmaceuticals was obtained at all 11 sites and their distribution patterns were identical. It was therefore impossible to distinguish the infected from the noninfected pseudarthroses by using Ga-67.

Mechanism of tumor and liver concentration of 67Ga: 67Ga binding substances in tumor tissues and liver

Tumor-bearing animals were administered with 67Ga citrate and tumor homogenates, from which nuclear fraction was removed, and mitochondrial fraction of the host livers were digested with protease (pronase P). After digestion, the supernatants of the reaction mixtures were applied to a Sephadex G-100 column. Resultant eluates were analyzed for radioactivity, protein, uronic acid and sialic acids. Three peaks of radioactivity were obtained by gel filtration. The first peak eluted in the void volume contained a species whose molecular weight exceeded 40,000. The second peak consisted of substances with molecular weights of 9400–40,000. Radioactivity in the third peak was from liberated gallium-67. 67Ga in the second peak was bound to acid mucopolysaccharide and/or the sulfated carbohydrate chain of sulfated glycoprotein. It was thought that 67Ga in the first peak might be bound to some acid mucopolysaccharides. Considering the results of cellulose acetate electrophoresis, 67Ga in the second peak seemed to be bound to acid mucopolysaccharide which contained no uronic acids, and/or to the sulfated carbohydrate chain of sulfated glycoprotein. It was concluded that 67Ga was bound to the acid mucopolysaccharides and/or the sulfated carbohydrate chain of sulfated glycoprotein in tumor tissues and liver lysosomes.

Desferal (DFO) induced 67Ga washout from normal tissue, tumor and abscess in experimental animals

In the experimental animal, desferal (DFO) given intravenously washes out Ga-67 from all tissues. This effect is not uniform: blood activity is reduced very markedly, while liver activity is less affected. Maximal effect of DFO occurs if given close to the Ga-67 injection. When the time interval between the two is increased, the absolute amount of Ga-67 excreted in the urine in excess of the spontaneous excretion is reduced. Administration of DFO does not effect Ga-67 gastrointestinal excretion. In three animal tumor models (EMT-6 sarcoma in Balb/c mice, spontaneous adenocarcinoma in mice, and spontaneous adenocarcinoma in the rabbit) and in sterile abscess-bearing rats, the administration of DFO 24 hrs after Ga-67-citrate improves significantly the target-to-nontarget ratio. Animals given 50 mg/kg DFO I.V. after Ga-67 citrate showed a significant reduction in the whole-body activity as seen in a one-week follow up.

The importance of the lateral view in Ga-67 citrate imaging of the thorax. Esophageal carcinoma.

DUONG, RAYMOND B. M.D.; SILBERSTEIN, EDWARD B. M.D.; FERNANDEZ-ULLOA, MARIANO M.D. Author Information