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Biomedical subjects

N Oriuchi

Publications and source records attributed to N Oriuchi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Fundamental study of hot spot detectability in 3-dimensional positron emission tomography.

The purpose of this study was to investigate the detectability of small hot lesions with the 3-dimensional transmission/emission (3D T/E) acquisition mode in FDG-PET scan. The correlation of target detectability, target size, target to non-target uptake ratio (T/N ratio) and standardized uptake value (SUV) were studied. Small hot lesions ranged from 4.4 mm to 36.9 mm in diameter were located in cylindrical phantom. The images of phantoms with a T/N ratio of 2.0, 4.0, 6.0, 8.0, 9.6, 13.2, 17.5, 23.8 and 30.3 were obtained with 2-dimensional transmission/emission (2D T/E) scan and 3D T/E scans. Targets in diameter more than 10.6 mm in diameter with an actual T/N ratio ranged from 6.0 to 30.3 could be identified on the images obtained with all the 2D T/E and 3D T/E acquisition modes. The detectability efficiency of small hot target in 2D T/E and 3D T/E scans was as same (77.8%). The T/N ratio of targets from 2D T/E images was 30% to 48.4% different to that from 3D T/E image, and the SUV of the target from the 2D T/E images was almost the same as that from 3D T/E images. This study revealed that 3D T/E scanning had similar hot spot detectability to 2D T/E scanning; 3D T/E and 2D T/E scanning had the same faculty for semiquantitative analysis using SUV. These findings may be helpful for the diagnosis and understanding of 3D T/E FDG-PET in hot lesion detection.

Fluorine Radioisotopes↗
PubMed2000

FDG PET in the clinical evaluation of sarcoidosis with bone lesions.

We report a case of sarcoidosis with osseous involvement. Whole-body fluorine-18-fluorodeoxyglucose (FDG) PET scanning demonstrated multiple sites of FDG uptake in the hilar lymph nodes, right ulna, bilateral feet, and subcutaneous tissue of the extremities. FDG PET scanning provides useful information for the detection of sarcoidosis with systemic distribution, even when osseous lesions are included.

Adult↗
PubMed2000

Accuracy of carboxyhemoglobin dilution method for the measurement of circulating blood volume.

PURPOSE: The management of circulating blood volume (BVc) is crucial in intensive care unit (ICU) patients. The purpose of this study was to verify the accuracy and precision of the carbon monoxide-labeled hemoglobin (CO-Hb) dilution method (CO method) by comparing it with the 51Cr-labeled erythrocyte dilution method (51Cr method) for the measurement of BVc. METHODS: A prospective study was performed in 18 patients who underwent coronary artery bypass grafting (CABG) under mild hypothermic cardiopulmonary bypass (CPB). The BVc was measured by both the CO method and the 51Cr method at 24 hr after ICU admission in order to verify the accuracy and precision of the CO method. Paired data were assessed in absolute terms, and percentage errors were calculated by the degree of agreement. RESULTS: Small mean differences and standard deviations between the CO method and the 51Cr method (-70.2 +/-184.8 mL) and small percentage errors (-0.49+/-1.29%) indicated the accuracy and precision of the CO method, and a close correlation was observed (r = 0.97). CONCLUSION: The CO method can measure BVc with a similar degree of accuracy as the 51Cr method. It is simple, repeatable and safe without the risk of exposure to radioactivity in the ICU.

Blood Volume↗
PubMed2000

Changes in gastric intramucosal pH and circulating blood volume following coronary artery bypass grafting.

PURPOSE: To determine the changes in gastric intramucosal pH (pHi) following coronary artery bypass grafting (CABG) in comparison with systemic hemodynamic variables and circulating blood volume (BVc). METHODS: Twenty patients who underwent CABG under mild hypothermic cardiopulmonary bypass (CPB) were included. Hemodynamic variables and the values of pHi were obtained at 3,6, 12 and 24 hr after admission to the intensive care unit (ICU). The pHi was measured by gastric tonometric catheter. The BVc was measured by carbon monoxide (CO)-labeled hemoglobin (CO-Hb) dilution method (CO method) at 6 and 24 hr after ICU admission. RESULTS: Systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) decreased with time. Systemic oxygen delivery index (DO2I) and systemic oxygen consumption index (VO2I) showed a gradual increase during the study period. By contrast, pHi decreased to the lowest value (7.26+/-0.05) at six hours and returned to normal levels (7.34+/-0.04) at 24 hr after ICU admission. Changes in BVc between six and 24 hr ranged from -242 ml to 978 ml (mean, 334+/-338 ml). The pHi increased in patients whose BVc increased by > 300 ml. Mean fluid balance was negative in this period (-386+/-667 ml; range, -1786 - + 423 ml). CONCLUSION: The pHi showed the lowest value at six hours and returned to normal at 24 hr after ICU admission. The pHi increased with the decrease in vascular resistance and with the increases in BVc in this period. The improvement of pHi, an indicator of splanchnic perfusion, appears to be related to systemic vasodilatation and an increase in BVc.

Aged↗
PubMed2000

PET imaging of musculoskeletal tumours with fluorine-18 alpha-methyltyrosine: comparison with fluorine-18 fluorodeoxyglucose PET.

Fluorine-18 labelled alpha-methyltyrosine (FMT) was developed for positron emission tomography (PET) imaging, and its potential for clinical application in patients with brain tumours has been demonstrated. This is the first trial to compare FMT with 18F-fluoro-2-deoxy-D-glucose (FDG) for the evaluation of musculoskeletal tumours. Seventy-five patients were examined with both FMT- and FDG-PET within a 2-week period. Imaging findings were visually inspected in conjunction with computed tomography and/or magnetic resonance imaging, and standardized uptake values (SUVs) for both FMT and FDG in lesions were also generated and compared with histological findings. A significant correlation between FMT and FDG SUVs was found for all lesions (r=0.769, P<0.0001), and mean values for malignant tumours were significantly higher than those for benign lesions in both FMT- and FDG-PET. The diagnostic sensitivities and specificities for malignancy were 72.7% and 84.9%, respectively, using FMT with a cut-off SUV of 1.2, and 72.7% and 66.0%, respectively, using FDG with a cut-off SUV of 1.9. The resultant accuracy with FMT was 81.3%, higher than that for FDG (68.0%), and the difference with respect to specificity was significant (chi2cal=5.0625, P<0.05). On the other hand, while a significant correlation was found between malignant tumour grade and SUV with both FMT- (rho=0.656) and FDG-PET (rho=0.815), only the latter demonstrated significant differences among grades I, II and III. FMT and FDG for PET appear equally effective at detecting musculoskeletal tumours. In evaluating musculoskeletal tumours, FMT may be superior to FDG in the differentiation between benign and malignant tumours, while FDG may be the better choice for non-invasive malignancy grading.

Adolescent↗
PubMed2000

Tumor uptake of radioiodinated anti-human pulmonary surfactant-associated protein monoclonal antibody PE10 in nude mice bearing human pulmonary adenocarcinoma in combination with an unlabeled preload.

This study assessed the potential use of radioimmunoscintigraphy of pulmonary alveolar Type II cells tumor with the radiolabeled anti-human surfactant-associated protein (SP) monoclonal antibody (MAb) PE 10 in combination with preloads of unlabeled MAb. The in vitro binding of iodine-125 ((125)I)-labeled MAb PE 10 (1 microg), which had a specific radioactivity of 400 MBq/mg, on human pulmonary papillary adenocarcinoma NCI-H441 cells that produced SP was investigated. In NCI-H441 tumor-bearing nude mice, the tumor uptake of (125)I-MAb PE 10 (5 microg) was examined in combination with preloads of unlabeled MAb PE 10 (0, 5, 10, and 50 microg). An isotype-matched unassociated murine MAb was used as a control both in vitro and in vivo. (125)I-MAb PE 10 showed specific cell binding compared with (125)I-control MAb. Tumor uptake of (125)I-MAb PE 10 in vivo reached a peak of 4.97+/-0.33% injected dose per gram (%ID/g) at 48 h postinjection. Preloads of 5 and 10 microg unlabeled MAb PE 10 significantly enhanced tumor uptake at 48 h postinjection ( 5.94+/-0.29% ID/g and 5.72+/-0.29% ID/g, respectively), whereas preload of 50 microg unlabeled MAb PE 10 significantly decreased tumor uptake ( 2.75+/-0.32% ID/g) at 48 h. Preload of 5 microg unlabeled MAb PE 10 significantly increased the tumor-to-blood radioactivity ratio at 48 h ( 2.39+/-0.16). Preloads of unlabeled control MAb did not cause any significant change in tumor uptake. Immunohistochemistry showed the intracellular and pericellular patterns of SP expression in tumor cells. In conclusion, radioimmunoscintigraphy with MAb PE 10 labeled with a gamma-emitting radioiodine such as (123)I might be a useful means of targeting pulmonary alveolar Type II tumor cells in combination with preloading with an optimal dose of the unlabeled MAb.

Adenocarcinoma↗
PubMed2000

Assessment of resistance to paclitaxel of murine tumors by (99m)Tc-MIBI/(201)Tl dual-radionuclide imaging.

This study investigated P-glycoprotein (Pgp) expression by murine tumors with and without resistance to paclitaxel and the role of (99m)Tc-2-methoxyisobutylisonitrile (MIBI)/(201)Tl imaging in predicting the effect of paclitaxel. Antitumor effect of paclitaxel and biodistribution of the radiopharmaceuticals were evaluated in mice bearing four tumor types. Pgp expression did not correlate with the antitumor efficacy of paclitaxel. Although the absolute uptake of (99m)Tc-MIBI did not correlate with Pgp expression, (99m)Tc-MIBI could predict paclitaxel sensitivity by its higher uptake.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

FR167653 ameliorates pulmonary damage in ischemia-reperfusion injury in a canine lung transplantation model.

BACKGROUND: Interleukin (IL)-1 and tumor necrosis factor-alpha (TNF-alpha) are recognized as important factors in ischemia-reperfusion (I/R) injury. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. We previously reported that FR167653 suppressed the expression of IL-1 beta mRNA after reperfusion and ameliorated pulmonary I/R injury following 3-hour left lung warm ischemia in dogs. The aim of this study was to investigate the effects of FR167653 on I/R injury in a canine left, single, lung transplantation model. METHODS: We used 10 pairs of weight-matched dogs. We assigned 5 pairs to the FR group, in which each animal received FR167653 (1 mg/kg/hr) IV from 30 minutes before ischemia until 2 hours after reperfusion; we treated the transplanted lungs with FR167653 after the onset of reperfusion. The others were assigned to the control group. After 8-hour preservation with 4 degrees C Euro-Collins solution, orthotopic left, single, lung transplantation was performed. During a 5-minute clamping test at the right pulmonary artery of each recipient, the left (transplanted) pulmonary arterial pressure (L-PAP), left (transplanted) pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. We harvested transplanted lung specimens for histologic study, and we counted polymorphonuclear neutrophils (PMNs), which were identified by staining with naphthol AS-D cholroacetate esterase. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. We observed the animals for 3 days after transplantation. RESULTS: The PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FR group than in the control group. Histologically, lung edema was milder, and PMN infiltration was significantly (p < 0.05) lower in the FR group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FR group. Three-day survival rates in FR and control groups were 60% and 20%, respectively. CONCLUSIONS: FR167653 appears to generate a protective effect on I/R injury in lung transplantation in dogs.

Animals↗
PubMed2000

The effect of FK409-a nitric oxide donor-on canine lung transplantation.

BACKGROUND: Nitric oxide (NO) is known to have beneficial effects in ischemia-reperfusion (I/R) injury through maintaining endothelial integrity, inhibiting leukocyte adhesion and platelet aggregation, and inducing vasodilation. The effect of FK409 (FK), a spontaneous NO donor, was investigated in a canine lung transplantation model. METHODS: Ten pairs of weight-matched dogs were used. Five pairs were assigned to the FK group, to which FK (5 microg/kg/min) was administered intravenously from 30 minutes prior to ischemia until the induction of ischemia in the donor, and from 15 minutes prior to reperfusion until 45 minutes after reperfusion in the recipient. The others were assigned to the control group. After 8-hour preservation in 4 degrees C Euro-Collins solution, orthotopic single-lung transplantation was performed. During a 5-minute clamping test of the right pulmonary artery, left pulmonary arterial pressure (L-PAP), left pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. The lung specimens were harvested for histologic study, and polymorphonuclear neutrophils (PMNs) were counted. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. RESULTS: PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FK group than in the control group. Histologically, edema was more mild, and PMN infiltration was significantly (p < 0.05) lower in the FK group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FK group. The 2-day survival rate was 100% in the FK group, which was significantly (p < 0.05) better than the rate (40%) in the control group. CONCLUSIONS: FK appears to generate a protective effect on I/R injury in lung transplantation.

Animals↗
PubMed2000

CaNa2EDTA for improvement of radioimmunodetection and radioimmunotherapy with 111In and 90Y-DTPA-anti-CEA MAbs in nude mice bearing human colorectal cancer.

UNLABELLED: 111In and 90Y, dissociated from 111In-labeled-monoclonal antibody (MAb) and 90Y-labeled MAb, may cause deterioration of the image quality in radioimmunodetection (RID) and undesirable irradiation of nontargeted tissue in radioimmunotherapy (RIT), respectively. The aim of this study was to investigate any improvement in RID and RIT with 111In-MAb and 90Y-MAb by pre- and postadministration of calcium disodium ethylenetriaminetetraacetic acid (CaNa2EDTA). METHODS: Murine MAb F33-104 against carcinoembryonic antigen (CEA) was labeled with 111In or 90Y by the diethylenetriamine pentaacetic (DTPA)-anhydride method. The influence of CaNa2EDTA on loss of radioactivity from 111In-MAb or 90Y-MAb in serum was investigated in vitro. The effects of CaNa2EDTA, administered before and after 111In-MAb or 90Y-MAb, on the biodistribution of radioactive isotopes in nude mice bearing human colon adenocarcinoma LS 180 tumor expressing CEA, or human pulmonary carcinoma PC 9 tumor expressing no CEA, were then examined. As a control, 0.9% NaCl was used in both the in vitro and in vivo studies. RESULTS: CaNa2EDTA did not cause any decrease in levels of radioactivity of radiolabeled MAbs. Pre- and post-treatment with CaNa2EDTA reduced radioctivity in both specific and nonspecific tumors at 72 h after 111In-MAb injection resulting in an increase of the specific tumor-to-nonspecific tumor radioactivity ratio. The levels of hepatic and renal radioactivity were also subsequently decreased by CaNa2EDTA. On the other hand, CaNa2EDTA pre- and post-treatment reduced levels of bony, hepatic, and renal radioactivity at 24, 72, and 72 h, respectively, after 90Y-MAb injection, although it had no effect on tumor radioactivity. CONCLUSION: Pre- and post-treatment with CaNa2EDTA would be of great use in humans who undergo RID or RIT with 111In-MAb and 90Y-MAb accompanied by disassociation of the labeled radionuclides.

Animals↗
PubMed1999

Evaluation of In-111 DTPA-paclitaxel scintigraphy to predict response on murine tumors to paclitaxel.

UNLABELLED: Our goal was to determine whether scintigraphy with 111In-DTPA-paclitaxel could predict the response to chemotherapy with paclitaxel. METHODS: Ovarian carcinoma (OCA 1), mammary carcinoma (MCA-4), fibrosarcoma (FSA) and squamous cell carcinoma (SCC VII) were inoculated into the thighs of female C3Hf/Kam mice. Mice bearing 8 mm tumors were treated with paclitaxel (40 mg/kg). The growth delay, which was defined as the time in days for tumors in the treated groups to grow from 8 to 12 mm in diameter minus the time in days for tumors in the untreated control group to reach the same size, was measured to determine the effect of paclitaxel on the tumors. Sequential scintigraphy in mice bearing 10 to 14 mm tumors was conducted at 5, 30, 60, 120, 240 min and 24 hrs postinjection of 111In-DTPA-paclitaxel (3.7MBq) or 111In-DTPA as a control tracer. The tumor uptakes (% injection dose/pixel) were determined. RESULTS: The growth delay of OCA 1, MCA-4, FSA and SCC VII tumors was 13.6, 4.0, -0.02 and -0.28 days, respectively. In other words, OCa 1 and MCA-4 were paclitaxel-sensitive tumors, whereas FSA and SCC VII were paclitaxel-resistant tumors. The tumor uptakes at 24 hrs postinjection of In-111 DTPA paclitaxel of OCA 1, MCA-4, FSA and SCC VII were 1.0 x 10(-3), 1.6 x 10(-3), 2.2 x 10(-3) and 9.0 x 10(-3) % injection dose/pixel, respectively. There was no correlation between the response to chemotherapy with paclitaxel and the tumor uptakes of 111In-DTPA-paclitaxel. CONCLUSIONS: Scintigraphy with 111In-DTPA-paclitaxel could not predict the response to paclitaxel chemotherapy. Although there was significant accumulation of the paclitaxel in the tumor cells, additional mechanisms must be operative for the agent to be effective against the neoplasm. 111In-DTPA-paclitaxel activity is apparently different from that of paclitaxel with Cremophor.

Animals↗
PubMed1999

Effect of edetate calcium disodium on yttrium-90 activity in bone of mice.

The kinetics of Yttrium-90 (Y-90) in bone of mice was investigated in combination with edetate calcium disodium (CaNa2EDTA). One group of mice were intraperitoneally administered 37.5 mg/kg CaNa2EDTA or 0.9% NaCl as a control at 1, 22, 34, 46, 58, 70, 82, 94, 154 and 166 h after injection of Y-90 acetate (post-administration), and the biodistribution was studied at 3, 24, 72, 120 and 168 h postinjection of Y-90 acetate. No difference between the post-CaNa2EDTA-treated mice and the control was demonstrated in the radioactivity in the bone. A decrease in radioactivity in the liver and kidneys was accelerated, and the radioactivity was lower than the control at 120 h postinjection. The other group of mice were also given the same dose of chelator at 12 h and 1 h preinjection of Y-90 acetate and at 1, 22, 34, 46, 58, 70, 82, 94, 154 and 166 h after injection of Y-90 acetate (pre- and post-administration), the radioactivity in bone at 3 h postinjection was significantly lower than in the control (24.4 +/- 3.92% ID/g vs. 31.7 +/- 2.26% ID/g, p < 0.05), but the decrease was not sequential. A significant reduction in radioactivity in the blood, kidneys and liver was demonstrated at 3 h, 72 h and 72 h postinjection. In conclusion, the CaNa2EDTA with the administration schedule employed here cannot chelate the Y-90 from bone but the free Y-90 before deposition into bone.

Animals↗
PubMed1999

Localization of indium-111 in human malignant tumor xenografts and control by chelators.

The kinetics of soluble indium-111 ((111)In) in human malignant tumor xenografts and cells was investigated in combination with chelators. Firstly, without chelator, the kinetics of (111)In-chloride was investigated in vitro and in vivo using four human malignant neuroblastoma SK-N-MC, pulmonary papillary adenocarcinoma NCI-H441, pulmonary squamous cell carcinoma PC 9, and colon adenocarcinoma LS 180 cells and xenografts. (111)In was incorporated into tumor cells in vitro to a maximum level during a 60-min incubation. A maximum level of radioactivity was demonstrated in vivo in four human malignant tumors xenografted into nude mice at 24 h postinjection of (111)In-chloride. Secondly, the effect of edetate calcium disodium (CaNa2EDTA) on radioactivity in (111)In-labeled tumors xenografts and cells was studied in vitro and in vivo. CaNa2EDTA significantly reduced (111)In-activity from the labeled tumor xenografts, whereas it had no affect on the radioactivity in the labeled cells. Thirdly, the effect of CaNa2EDTA on radioactivity in human malignant tumors xenografted into nude mice injected with (111)In-chloride was investigated. In one group of mice CaNa2EDTA administered intraperitoneally at 1, 22, 34, 46, 58, and 70 h after injection of (111)In-chloride (postadministration), the localization of (111)In at the tumors was significantly decreased at 72 h compared with the control in all four tumor types. In the other group of mice, CaNa2EDTA administered intraperitoneally at 12 and 1 h before injection of (111)In-chloride and 1, 22, 34, 46, 58, and 70 h postinjection (pre- and postadministration), the radioactivity of tumors was also significantly decreased at 72 h, and the reduction was greater than that with use of postadministration. In a comparative study, CaNa3DTPA had a more powerful effect than CaNa2EDTA. In conclusion, (111)In-activity in tumors consists of intracellular and extracellular components, and the extracellular (111)In may be cleared by chelators. Pre- and postadministration of CaNa3DTPA could remove (111)In-nonspecific localization in tumors when (111)In is released from the radiolabeled agents.

Animals↗
PubMed1999

Yttrium-90-labeled human macroaggregated albumin for internal radiotherapy: combined use with DTPA.

The aim of this study was to investigate the possibility of yttrium-90-labeled human macroaggregated albumin (90Y-MAA) as an internal radiotherapeutic agent for whole-lung irradiation in combination with diethylenetriamine pentaacetic acid (DTPA). The influence of trisodium calcium DTPA (CaNa3DTPA) on the radioactivity of 90Y-MAA in serum was investigated in vitro. The effect of CaNa3DTPA on the biodistribution of radioactivity in normal mice intraveneously injected with 90Y-MAA was examined. CaNa3DTPA could deprive in vitro radioactivity of 90Y-MAA in 48-h incubation. Most of the radioactivity (>90% injected dose per lung) was observed at murine lung after injection of 90Y-MAA. Pulmonary radioactivity was cleared within 72 h postinjection, whereas the radioactivities in the bone, liver, kidneys, and spleen increased with a peak at 48 h. CaNa3DTPA-treatment reduced the in vivo radioactivities in bone, liver, and kidneys without influence on the radioactivity of lung. In conclusion, combined use of CaNa3DTPA enables 90Y-MAA to be used as a radiopharmaceutical for internal irradiation against whole lung.

Albumins↗
PubMed1999

Biodistribution studies of the 186Re complex of 3-amino-1-hydroxypropylidene-1,1-bisphosphonic acid in mice.

Preliminary studies of 186Re-labelled 3-amino-1-hydroxypropylidene-1, 1-bisphosphonic acid (APD) were performed to determine its potential for bone pain palliation, and as a treatment for increased bone resorption. The synthesis of 186Re-APD was carried out by reduction of 186Re-perrhenate in the presence of SnCl2. The APD kit, comprising 2.5 mg of APD, 2.5 mg of gentisic acid and 1 mg of Sn++ as SnCl2 2H2O, was prepared in-house. The APD was labelled with 186Re and injected intravenously into normal mice. Mice were subsequently sacrificed at 1, 3, 24, 48, 72, 168 and 240 h post-injection. The greatest accumulation of 186Re-labelled APD was found in bone, resulting in bone-to-blood ratios of 25, 35, 65, 100, 151, 181 and 189, respectively. 186Re-APD showed high uptake in bone, and relatively low uptake in soft tissue, suggesting that 186Re-APD is a potential agent for bone therapy.

Animals↗
PubMed1999

Accuracy of standardized uptake value measured by simultaneous emission and transmission scanning in PET oncology.

We assessed the accuracy of the standardized uptake value (SUV) measured by simultaneous emission and transmission scanning in cancer patients using FDG positron emission tomography (PET). Conventional, independent emission (E)/transmission (T) scans and simultaneous E/T scans were conducted consecutively in 30 patients who underwent FDG PET examinations. The SUVs of 35 mass lesions and 34 selected normal tissues were derived from the independent E/T scan and simultaneous E/T scan. Experimental studies using a cylindrical phantom were also conducted to evaluate the accuracy and reproducibility of the SUV derived from a simultaneous E/T scan. The SUVs of 18F solution in the phantom were estimated to be approximately 1, with high reproducibility in the range of total counts observed in the clinical examinations. There were no significant differences in the SUVs in 35 tumours derived from simultaneous E/T scans and those derived from independent scans, and there was a strong positive correlation between the two (r = 0.99, P < 0.01). There were also no significant differences in the SUVs in 34 normal tissue regions derived from simultaneous E/T scans and those derived from independent scans. In conclusion, simultaneous E/T scanning with FDG in patients with malignant tumours is a valid method, since the SUV derived from the simultaneous scan is accurate and reproducible.

Algorithms↗
PubMed1999

18F alpha-methyl tyrosine PET studies in patients with brain tumors.

UNLABELLED: We have developed 18F-labeled alpha-methyl tyrosine (FMT) for PET imaging. The aim of this study was to evaluate the clinical application potential of FMT for patients with brain tumors. METHODS: Eleven healthy volunteers and 20 patients with brain tumors were injected with 185 MBq (5 mCi) FMT. In 3 healthy volunteers, whole-body imaging and urinary and plasma analysis were conducted for the assessment of the biodistribution of FMT. The normal range of cortical standardized uptake value (SUV) as a reference for comparing tumor SUV of FMT was estimated by using PET data obtained at 30 min postinjection in 8 healthy volunteers. Dynamic PET scans were conducted for 100 min in 4 healthy volunteers and for 30 min in 15 patients with brain tumors. The 10-min static images in another 4 volunteers and all patients were obtained at 30 min postinjection. In 13 patients, FMT uptake in the brain tumor was compared with 18F-fluorodeoxyglucose (FDG). Tumor-to-normal cortex count (T/N) ratio and tumor-to-white matter count (T/W) ratio and SUVs of brain tumors were determined on FMT and FDG PET images. RESULTS: Approximately 1480 MBq (40 mCi) FMT were produced in one radiosynthesis. Percentage injected dose (%ID) of FMT in the brain ranged from 2.8% to 4.9%, and approximately 50%ID of FMT was excreted in urine during 60 min postinjection, of which 86.6% was unmetabolized FMT. A faint physiological brain uptake with SUV of 1.61 +/- 0.32 (mean +/- SD, n = 8) was observed in healthy volunteers. Tumor SUV of FMT ranged from 1.2 to 8.2, with mean value of 2.83 +/- 1.57 (n = 23), which was significantly higher than that of the cortical area in healthy volunteers (P < 0.01). T/N and T/W ratios of FMT were significantly higher than those of FDG (2.53 +/- 1.31 versus 1.32 +/- 1.46, P < 0.001; 3.99 +/- 2.10 versus 1.39 +/- 0.65, P < 0.0001, respectively). CONCLUSION: FMT, like other radiolabeled amino acids, can provide high-contrast PET images of brain tumors.

Adolescent↗