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A case of gallium localization within the breast occurred secondary to intravenous drug abuse. In the appropriate clinical setting, prior self-administered injections should be considered as a cause of Ga-67 accumulation at unusual sites.
A rare case of an intravascular neoplastic obstruction of the superior vena cava is discussed. The lesion was detected with gallium single photon emission computed tomography (SPECT) despite a normal appearance on a concurrent radiographic CT study. A computer-generated composite SPECT-CT image confirmed the intravascular localization of the radioisotope, and a subsequent CT-guided transthoracic needle biopsy revealed a poorly differentiated adenocarcinoma.
A patient with idiopathic retroperitoneal fibrosis with a positive Ga-67 scan was successfully treated with steroids. Administration of methylprednisolone improved the ureteral obstruction and gallium accumulation also disappeared.
Malignant external otitis (MEO) is a recognized entity characterized by a stubborn Pseudomonas external otitis; it has been most frequently observed in elderly diabetic patients. Early diagnosis is necessary for successful treatment but, despite a widespread inflammatory response, routine plain x-ray studies and computed tomography (CT) scanning show no abnormalities in its early stage. In this report, the clinical value of gallium 67 (Ga 67) single photon emission CT (SPECT) is studied in three patients suspected of having MEO, and the results are compared with findings on CT scan and laboratory tests. These results confirm that the high sensitivity of GA 67 SPECT in the initial recognition of MEO provides a more adequate technique than CT scan. Furthermore, Ga 67 scintigraphy appears to be highly accurate for follow-up evaluation of these patients.
A variety of computer-derived indices of pulmonary gallium-67 were compared in 51 subjects with and without interstitial lung disorders. An index which quantitates lung uptake in relation to liver uptake, both being corrected for tissue background activity over the thigh, was the most reliable in differentiating between the two patient groups. The index is easily derived using standard computer techniques, so permitting further studies to assess its role in serial assessments of the progress of these disorders.
A septic course suggestive of intra-abdominal abscess followed surgery in a small child with a perforated appendix. Usual diagnostic studies, fluoroscopy, and rectal and wound exploration failed to localized an abscess. The use of gallium 67 scanning accurately localized multiple abscesses which were successfully drained.
We have described a patient with Hodgkin's disease who had fever and pulmonary infiltrates after treatment with mantle x-ray therapy and two courses of MOPP. Gallium affinity of the lung lesions proved at biopsy not to be due to Hodgkin's disease, but probably to chemotherapy-induced pulmonary toxicity.
Injectable gallium (Ga) nitrate, approved in the United States for the treatment of hypercalcemia of malignancy, has been known for more than 2 decades to have immunosuppressive properties. At therapeutic doses, it has few adverse effects, although high-dose infusions may result in severe nephrotoxicity, particularly in patients who are not adequately hydrated, and severe anemia. In animal models, Ga has been shown to have efficacy in the treatment of adjuvant arthritis, type 1 diabetes, experimental autoimmune encephalomyelitis, experimental pulmonary inflammation, cardiac allograft rejection, experimental autoimmune uveitis, endotoxic shock, and systemic lupus erythematosus. Clinical trials have demonstrated efficacy in Paget's disease of bone and activity against some malignancies, including epithelial ovarian carcinoma, non-squamous cell carcinoma of the cervix, bladder cancer, and non-Hodgkin's lymphoma. Other clinical trials underway include studies of sarcoidosis and rheumatoid arthritis. Future studies should be conducted not only in other autoimmune diseases, such as multiple sclerosis, but also in graft-versus-host disease, leprosy, and acquired immunodeficiency syndrome (AIDS).
A 70-year-old man presented with 6 weeks of worsening low back pain, fever, sweating, and weight loss with known severe lumbosacral osteoarthritis. His history included CABG in 1992, porcine aortic valve replacement, and permanent pacemaker implantation in 2002. CT of the chest, abdomen, and pelvis did not demonstrate a cause for the symptoms. Blood cultures grew penicillin-sensitive enterococcus and he was referred for evaluation of possible osteodiskitis or epidural abscess. Gallium planar imaging demonstrated increased activity in the lumbar spine, suspicious for the presence of infection, and activity was noted in the mid mediastinum as well. SPECT clearly showed increased Ga-67 activity in the region of the aortic root, suspicious for infection. A perivalvular aortic root abscess was subsequently demonstrated by transesophageal echo. This case illustrates the value of Ga-67 chest SPECT in patients with prosthetic valves for detection of endocarditis.
A 33-year-old woman with a diagnosis of Hodgkin's disease had a prechemotherapy whole-body Ga-67 scan to document gallium avidity of lesions and to assess response to therapy. A posttherapy scan showed a discordant response with complete resolution of lymphadenopathy and persistence of bone lesions. Radiographic evaluation of the left humerus, radius, and ulna demonstrated typical fibrous dysplasia as a cause for persistence of Ga-67 activity and shoulder activity probably representing arthropathy. She was in remission 3 years later although she fell and fractured the humerus through the bony lesion, and biopsy at the time of internal fixation confirmed fibrous dysplasia.
A 63-year-old female patient with a recent left posterior cerebral artery infarction and pyelonephritis presented with persistent fevers despite adequate intravenous antibiotic therapy. Whole-body gallium-67 scintigraphy was performed to evaluate for occult infection. Tracer accumulated bilaterally in the kidneys consistent with the previously diagnosed pyelonephritis. Relatively intense uptake was also noted in the area of a known occipitoparietal infarct. Incidentally noted was an abnormal focus of increased tracer uptake in the retroareolar region of the right breast. Subsequent guided core biopsy of the right breast mass demonstrated a previously undiagnosed invasive ductal carcinoma.
A family of planar gold RF microcoils were fabricated using microlithography on a gallium arsenide substrate. The microcoils were used in 1H nuclear magnetic resonance (NMR) spectroscopy experiments at 300 MHz (7.05 T). These new microcoils are a key component in the design of integrated MR coils and amplifiers for NMR microspectroscopy.
We describe a new approach to the problem of collimator optimization in nuclear medicine; our methodology is illustrated for the challenging case of gallium-67 imaging. Collimator-design methods based on empirical rules, such as specification of an allowable level of single-septal penetration (SSP) at a fixed energy, are especially inappropriate for radionuclides characterized by an abundance of high-energy contaminant photons that scatter in the patient, collimator, and/or detector before detection within one of a few photopeak energy windows. Lead X-rays produced in the collimator are an additional source of contamination. We designed optimal collimation for 67Ga based on relevant clinical imaging tasks and a realistic simulation of photon transport in a phantom, collimator, and detector. Collimator designs were compared on the basis of performance in lesion detection, as predicted by a three-channel Hotelling observer (CHO), as well as in tumor and background activity estimation (EST), quantified by task-specific signal-to-noise ratios (SNRs). The optimal values of collimator lead content were 22.0 and 23.8 g/cm2, respectively, for CHO and EST, while the optimal geometric resolution values were 1.8 and 1.6 cm full-width at half-maximum (FWHM), respectively, at a distance of 23.5 cm. The resolution of a commercially available medium-energy low-penetration collimator (MELP) is 1.9 cm FWHM at this distance. The optimal values for SSP at 300 keV were 7.3% and 5.8% based on CHO and EST, respectively, compared to 5.2% for the MELP collimator. Compared with the commercial MELP collimator, the 67Ga collimator optimized for tumor detection or activity estimation tasks provided improved geometric spatial resolution with reduced geometric efficiency and, surprisingly, allowed an increased level of single-septal penetration.
The HasA(SM) hemophore, secreted by Serratia marcescens, binds free or hemoprotein bound heme with high affinity and delivers it to a specific outer membrane receptor, HasR. In HasA(SM), heme is held by two loops and coordinated to iron by two residues, His 32 and Tyr 75. A third residue His 83 was shown recently to play a crucial role in heme ligation. To address the mechanistic issues of the heme capture and release processes, the histidine protonation states were studied in both apo- and holo-forms of HasA(SM) in solution. Holo-HasA(SM) was formed with gallium-protoporphyrin IX (GaPPIX), giving rise to a diamagnetic protein. By use of heteronuclear correlation NMR spectroscopy, the imidazole side-chain (15)N and (1)H resonances of the six HasA(SM) histidines were assigned and their pKa values and predominant tautomeric states according to pH were determined. We show that protonation states of the heme pocket histidines can modulate the nucleophilic character of the two axial ligands and, consequently, control the heme binding. In particular, the essential role of the His 83 is emphasized according to its direct interaction with Tyr 75.
The killing effects of heat were studied on cultured mammalian cells (L5178Y) pre-incubated with gallium (Ga) citrate, which is a popular tumor-imaging diagnostic agent. The cells showed higher sensitivity to heat when they were pre-incubated with Ga-citrate. The pre-incubated cells showed decreased ATP levels, and this may be responsible for the heat-sensitizing effect.
The sonodynamically induced antitumor effect of a gallium-porphyrin complex, ATX-70, was evaluated in mice bearing colon 26. In order to find the optimum timing for the ultrasonic exposure after the administration of ATX-70, the ATX-70 concentrations in the plasma, skin, and tumor were measured and analyzed. Antitumor effect was estimated by measuring the tumor size. When used alone, ultrasound showed a slight antitumor effect, which became increasingly significant as the dose of ATX-70 was increased, while use of ATX-70 alone had no significant effect. At an ATX-70 dose of 2.5 mg/kg or higher, the average tumor size decreased to smaller than a half by three days after the ultrasonic exposure. This was smaller than a third of the size of the untreated tumors on the same day. From these results, it is concluded that ATX-70 significantly sensitizes tumors to ultrasound, demonstrating a synergistic antitumor effect.
This case illustrates two interesting features. Firstly it describes an unusual cutaneous lymphoma in an adolescent girl. This lymphoma showed features of B and T cell lineages with rearrangements of both immunoglobulin heavy chain and T cell beta chain genes. Secondly it describes the development of gallium-67 citrate (67Ga) scan positive benign thymic hyperplasia, 15 months after diagnosis and three months after cessation of intensive chemotherapy.
BACKGROUND: Gallium-67 (Ga-67) is widely used in the assessment of patients with lymphoma. Although highly sensitive in Hodgkin's disease and high grade non-Hodgkin's lymphoma (NHL), its sensitivity is reported to be reduced in lower grades of NHL. Several series have suggested that thallium-201 (Tl-201) may be more useful than Ga-67 in the evaluation of low and possibly intermediate grade NHL. AIM: To compare the sensitivity and relative avidities (uptakes) of Tl-201 and Ga-67 in patients with NHL. METHODS: A total of 36 pairs of studies were performed in 33 patients (14 male: 19 female; age range 16-84 years, mean 55 years). All had whole body Ga-67 (400 MBq) and Tl-201 (100-200 MBq) studies (interval 0-three days) which were read by two experienced nuclear medicine physicians blinded to clinical history and results of other investigations. RESULTS: Tl-201 had a higher sensitivity and avidity than Ga-67 in patients with low grade NHL. In contrast, Ga-67 was slightly more sensitive and had a higher avidity in patients with both intermediate and high grade NHL. CONCLUSIONS: We conclude that Tl-201 is more sensitive and avid for low grade NHL than Ga-67 and that consideration should be given to its use in this condition in conjunction with Ga-67 as it may provide complementary information. Routine use in intermediate grade NHL is less convincing as Ga-67 was superior in most cases. Ga-67 is more sensitive than Tl-201 in assessment of high grade NHL.