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Toshiki Takei

Publications and source records attributed to Toshiki Takei.

10 recordsLinked to original sources
PubMed2005

Focal uptake on 18F-fluoro-2-deoxyglucose positron emission tomography images indicates cardiac involvement of sarcoidosis.

AIMS: To evaluate the value of (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) in detecting cardiac sarcoidosis. METHODS AND RESULTS: Thirty-two patients with sarcoidosis and thirty controls were recruited. All subjects underwent cardiac (18)F-FDG PET after a 6 h fasting period, and subjects with sarcoidosis underwent blood testing, ECG, echocardiography, and (67)Ga and (99m)Tc-sestamibi (MIBI) scintigraphy. We classified (18)F-FDG PET images into four patterns ('none', 'diffuse', 'focal', and 'focal on diffuse') and found that all the control subjects exhibited either none (n=16) or diffuse (n=14) pattern. In contrast, fifteen subjects with sarcoidosis exhibited none, seven exhibited diffuse, eight exhibited focal, and two exhibited focal on diffuse patterns, with the prevalence of the focal and focal on diffuse patterns being significantly higher in the sarcoidosis group when compared with the control group (P<0.001). None of the 32 subjects with sarcoidosis exhibited abnormal findings on (67)Ga scintigraphy, and 4 exhibited abnormal findings on (99m)Tc-MIBI scintigraphy. CONCLUSION: Focal uptake of the heart on (18)F-FDG PET images is a characteristic feature of patients with sarcoidosis. Furthermore, (18)F-FDG PET has the potential to detect cardiac sarcoidosis that cannot be diagnosed by (67)Ga or (99m)Tc-MIBI scintigraphy.

Adult↗
PubMed2005

Does lemon candy decrease salivary gland damage after radioiodine therapy for thyroid cancer?

UNLABELLED: Salivary gland dysfunction is one of the common side effects of high-dose radioiodine therapy for thyroid cancer. The purpose of this study was to determine whether an early start of sucking lemon candy decreases salivary gland injury after radioiodine therapy. METHODS: The incidence of the side effects of radioiodine therapy on the salivary glands was prospectively and longitudinally investigated in 2 groups of patients with postsurgical differentiated thyroid cancer with varying regimens for sucking lemon candy. From August 1999 to October 2000, 116 consecutive patients were asked to suck 1 or 2 lemon candies every 2-3 h in the daytime of the first 5 d after radioiodine therapy (group A). Lemon candy sucking was started within 1 h after radioiodine ingestion. From November 2000 to June 2002, 139 consecutive patients (group B) were asked to suck lemon candies in a manner similar to that of group A. In the group B, lemon candies were withheld until 24 h after the ingestion of radioiodine. Patients with salivary gland disorders, diabetes, collagen tissue diseases, or a previous history of radioiodine therapy or external irradiation to the neck were excluded. Thus, 105 patients in group A and 125 patients in group B were available for analysis. There were no statistical differences in the mean age (55.2 y vs. 58.5 y), average levels of serum free thyroxine (l-3,5,3',5'-tetraiodothyronine) (0.40 ng/dL vs. 0.47 ng/dL), and the mean dose of (131)I administered (3.96 GBq vs. 3.87 GBq) between the 2 groups. The onset of salivary side effects was monitored during hospital admission and regular follow-up on the basis of interviews with patients, a visual analog scale, and salivary gland scintigraphy using (99m)Tc-pertechnetate. When a patient showed a persistent (>4 mo) dry mouth associated with a nonfunctioning pattern on salivary gland scintigraphy, a diagnosis of xerostomia was established. RESULTS: The incidences of sialoadenitis, hypogeusia or taste loss, and dry mouth with or without repeated sialadenitis in group A versus group B were 63.8% versus 36.8% (P < 0.001), 39.0% versus 25.6% (P < 0.01), and 23.8% versus 11.2% (P < 0.005), respectively. Permanent xerostomia occurred in 15 patients in group A (14.3%) and 7 patients in group B (5.6%) (P < 0.05). In both groups, bilateral involvement of the parotid gland was the most frequently seen and was followed by bilateral involvement of the submandibular gland. CONCLUSION: An early start of sucking lemon candy may induce a significant increase in salivary gland damage. Lemon candy should not be given until 24 h after radioiodine therapy.

Administration, Oral↗
PubMed2005

Biologic correlates of intratumoral heterogeneity in 18F-FDG distribution with regional expression of glucose transporters and hexokinase-II in experimental tumor.

UNLABELLED: The biologic mechanisms involved in the intratumoral heterogeneous distribution of 18F-FDG have not been fully investigated. To clarify factors inducing heterogeneous 18F-FDG distribution, we determined the intratumoral distribution of 18F-FDG by autoradiography (ARG) and compared it with the regional expression levels of glucose transporters Glut-1 and Glut-3 and hexokinase-II (HK-II) in a rat model of malignant tumor. METHODS: Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle (n = 7). Tumor tissues were excised 1 h after the intravenous injection of 18F-FDG and sectioned to obtain 2 adjacent slices for ARG and histochemical studies. The regions of interest (ROIs) were placed on ARG images to cover mainly the central (CT) and peripheral (PT) regions of viable tumor tissues and necrotic/apoptotic (NA) regions. The radioactivity in each ROI was analyzed quantitatively using a computerized imaging analysis system. The expression levels of Glut-1, Glut-3, and HK-II were determined by immunostaining and semiquantitative evaluation. The hypoxia-inducible factor 1 (HIF-1) was also immunostained. RESULTS: ARG images showed that intratumoral 18F-FDG distribution was heterogeneous. The accumulation of 18F-FDG in the CT region was the highest, which was 1.6 and 2.3 times higher than those in the PT and NA regions, respectively (P < 0.001). The expression levels of Glut-1, Glut-3, and HK-II were markedly higher in the CT region (P < 0.001) compared with those in the PT region. The intratumoral distribution of 18F-FDG significantly correlated with the expression levels of Glut-1, Glut-3, and HK-II (r = 0.923, P < 0.001 for Glut-1; r = 0.829, P < 0.001 for Glut-3; and r = 0.764, P < 0.01 for HK-II). The positive staining of HIF-1 was observed in the CT region. CONCLUSION: These results demonstrate that intratumoral 18F-FDG distribution corresponds well to the expression levels of Glut-1, Glut-3, and HK-II. The elevated expression levels of Glut-1, Glut-3, and HK-II, induced by hypoxia (HIF-1), may be contributing factors to the higher 18F-FDG accumulation in the CT region.

Animals↗
PubMed2005

Enhanced apoptotic reaction correlates with suppressed tumor glucose utilization after cytotoxic chemotherapy: use of 99mTc-Annexin V, 18F-FDG, and histologic evaluation.

UNLABELLED: Cancer chemotherapy enhances the apoptosis, whereas apoptosis is a suicidal mechanism requiring energy. We determined the relationship between apoptosis and glucose utilization during cancer chemotherapy using (99m)Tc-annexin V ((99m)Tc-annexin A5) and (18)F-FDG and compared their uptake with histologic findings in a rat tumor model. METHODS: Allogenic hepatoma cells (KDH-8) were inoculated into the left calf muscle of male Wistar rats (WKA). Eleven days after the inoculation, the rats were randomly divided into 3 groups: The first group (n = 7) received a single dose of gemcitabine (90 mg/kg, intravenously), the second group (n = 8) received cyclophosphamide (150 mg/kg, intraperitoneally), and the third group (n = 7) was untreated and served as the control group. We injected (99m)Tc-annexin V 48 h after the chemotherapy and then injected (18)F-FDG to all rats 1 h before sacrifice. Six hours after (99m)Tc-annexin V injection, the rats were sacrificed and the organs, including the tumor, were removed and radioactivity was counted. The radioactivities of (18)F and (99m)Tc in the organs were determined using normalization by tissue weight. Histologic evaluation by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method and the immunostaining of glucose transporter-1 (GLUT-1) were also performed to obtain the indices of apoptosis and glucose utilization, respectively. The rate of positively stained cells was calculated and analyzed statistically. RESULTS: After chemotherapy using gemcitabine and cyclophosphamide, the (99m)Tc-annexin V uptake (percentage injected dose per gram x kg [(%ID/g) x kg]; mean +/- SD) in tumor increased significantly (0.062 +/- 0.012 (%ID/g) x kg in the gemcitabine-treated group and 0.050 +/- 0.012 (%ID/g) x kg in the cyclophosphamide group vs. 0.031 +/- 0.005 (%ID/g) x kg in the control group; P < 0.01). In contrast, the (18)F-FDG in tumor decreased significantly (0.483 +/- 0.118 (%ID/g) x kg in the gemcitabine group and 0.583 +/- 0.142 (%ID/g) x kg in the cyclophosphamide group) compared with that in the control group (0.743 +/- 0.084 (%ID/g) x kg; P < 0.01). In addition, (18)F-FDG uptake in tumor negatively correlated with (99m)Tc-annexin V uptake (r = -0.75; P < 0.01). In the gemcitabine and cyclophosphamide groups, the rate of TUNEL positively stained cells was significantly higher than that in the control group (10.2% +/- 1.7% and 8.0% +/- 1.5% vs. 5.2% +/- 1.5%; P < 0.01), whereas the GLUT-1 expression level showed no definite changes in histologic analyses. CONCLUSION: These data indicate that an enhanced apoptotic reaction correlated with suppressed tumor glucose utilization after cytotoxic chemotherapy as determined using radiotracers and histologic evaluation. The increase in (99m)Tc-annexin V and the decrease in (18)F-FDG in tumor can be useful markers for predicting therapeutic outcomes and for prognosis at the early stage of chemotherapy.

Animals↗
PubMed2004

18F-FDG PET is superior to 67Ga SPECT in the staging of non-Hodgkin's lymphoma.

OBJECTIVE: Our study aims to compare diagnostic accuracy between 18F-FDG PET and 67Ga SPECT in the staging of non-Hodgkin's lymphoma. METHODS: Twenty-eight patients with non-Hodgkin's lymphoma, underwent 18F-FDG PET, 67Ga SPECT and CT for the pretreatment staging of malignant lymphoma between August 1999 and March 2002. 18F-FDG PET imaging was obtained 60 minutes after the intravenous administration of 185 MBq of 18F-FDG. 67Ga SPECT imaging was obtained 2 days after the intravenous administration of 148 MBq of 67Ga. 18F-FDG PET and 67Ga SPECT were performed within one month. Both imagings were performed on the area from the neck to the pelvis. The 18F-FDG PET and 67Ga SPECT findings were compared with the CT findings and the clinical course. RESULTS: Sixty-six nodal lesions were clinically confirmed. Of these, 32 were identified by both 18F-FDG PET and 67Ga SPECT. The remaining 34 lesions were identified only by 18F-FDG PET. The mean (+/- SD) sizes' of the nodes were 34.7 +/- 32.4 mm for 18F-FDG-positive and 67Ga-positive lesions and 15.7 +/- 8.3 mm for 18F-FDG-positive and 67Ga-negative lesions (p < 0.001). Of the 23 extranodal lesions, 12 were identified by both 18F-FDG PET and 67Ga SPECT, whereas 6 lesions were identified by only 18F-FDG PET. Five lesions were not identified by either technique. No 18F-FDG-negative but 67Ga-positive nodal or extranodal lesions were observed. The difference in findings between the two studies is related to the difference in the size but not in the histology or site of the lesions. CONCLUSION: 18F-FDG PET detected significantly more lesions particularly small lesions than 67Ga SPECT. Thus, 18F-FDG PET is considered to be superior to 67Ga SPECT in the staging of non-Hodgkin' s lymphoma.

Citrates↗
PubMed2004

Feasibility of 99mTc-annexin V for repetitive detection of apoptotic tumor response to chemotherapy: an experimental study using a rat tumor model.

UNLABELLED: Annexin V (annexin A5), a human protein with a high affinity for phosphatidylserine, labeled with (99m)Tc can detect apoptosis in vivo. In the repetitive detection of apoptosis with (99m)Tc-annexin V, however, the specific binding of annexin V to phosphatidylserine might affect the subsequent detection of apoptosis with this compound. To determine whether there is interference with repetitive doses of annexin V, we evaluated the effects of previous administration of cold annexin V on accumulation of (99m)Tc-annexin V in tumors in an experimental tumor model. METHODS: Rats bearing hepatoma received cyclophosphamide (150 mg/kg, intraperitoneally) 11 d after the tumor inoculation. Cold annexin V (20 microg/kg, intravenously) was administered 24 h before or after the cyclophosphamide treatment (n = 7/group). (99m)Tc-Annexin V was injected intravenously (radioactive dose, 5-23 MBq/kg; mass dose, 20 microg/kg), and radioactivity in tissues was determined 6 h later. RESULTS: Accumulation of (99m)Tc-annexin V in tumors was not significantly affected by previous treatment with cold annexin V before or after chemotherapy. CONCLUSION: These results demonstrate the feasibility of (99m)Tc-annexin V imaging for repetitive detection of apoptosis, which is highly required in the clinical setting.

Animals↗
PubMed2004

Time course of apoptotic tumor response after a single dose of chemotherapy: comparison with 99mTc-annexin V uptake and histologic findings in an experimental model.

UNLABELLED: In tumors the process of apoptosis occurs over an interval of time after chemotherapy. To determine the best timing for detecting apoptosis in vivo with (99m)Tc-annexin V after chemotherapy, we examined the changes in (99m)Tc-annexin V accumulation over time in comparison with those of caspase-3 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) expression level after cyclophosphamide treatment in an experimental model. METHODS: Hydrazinonicotinamide (HYNIC)-annexin V was labeled with (99m)Tc ((99m)Tc-annexin V). Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle. Eleven days after the inoculation, the rats were randomly divided into the group receiving a single dose of cyclophosphamide (150 mg/kg intraperitoneally) and the control group. (99m)Tc-Annexin V (18.5 MBq [0.5 mCi] per rat) was injected intravenously in the rats 4, 12, and 20 h after the treatment and also to the control rats (n = 5 in each group). Radioactivity in tissues was determined 6 h after (99m)Tc-annexin V injection. Immunostaining of caspase-3 and TUNEL were performed to detect apoptosis, and the rates of positively stained cells were calculated. RESULTS: (99m)Tc-Annexin V accumulation in tumors significantly increased at 20 h (0.077 +/- 0.007 [%ID/g] x kg, where %ID/g = percentage injected dose per gram) but not at 4 or 12 h (0.048 +/- 0.008 and 0.052 +/- 0.014 [%ID/g] x kg, respectively) after cyclophosphamide treatment. (99m)Tc-Annexin V accumulation in tumors and the rate of apoptotic cells determined by caspase-3 immunostaining and TUNEL were significantly higher in treated rats 20 h after cyclophosphamide treatment as compared with control rats. CONCLUSION: The effective detection of apoptotic tumor response with (99m)Tc-annexin V required 20 h after cyclophosphamide treatment in an experimental model. The present results provide an important basis for determining the best timing of annexin V imaging after the start of chemotherapy in a clinical setting.

Animals↗
PubMed2002

Accumulation of [11C]acetate in normal prostate and benign prostatic hyperplasia: comparison with prostate cancer.

Carbon-11 acetate positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of prostate cancer. However, no detailed analysis has yet been carried out on the physiological accumulation of [(11)C]acetate in the prostate. The purpose of this study was to elucidate the physiological accumulation of [(11)C]acetate in the prostate using dynamic PET. The study included 30 subjects without prostate cancer [21 with normal prostate and nine with benign prostatic hyperplasia (BPH)] and six patients with prostate cancer. A dynamic PET study was performed for 20 min after intravenous administration of 555 MBq of [(11)C]acetate. The standardised uptake value (SUV) at 16-20 min post tracer administration and the early-to-late-activity ratio of the SUV (E/L ratio), which was determined by dividing the SUV(6-10 min) by the SUV(16-20min), were calculated to evaluate the accumulation of [(11)C]acetate. The prostate was clearly visualised and distinguished from adjacent organs in PET images in most of the cases. The SUV of the prostate (2.6+/-0.8) was significantly higher than that of the rectum (1.7+/-0.4) or bone marrow (1.3+/-0.3) ( P<0.0001 in each case). The SUV of the normal prostate of subjects aged <50 years (3.4+/-0.7) was significantly higher than both the SUV for the normal prostate of subjects aged > or =50 years (2.3+/-0.7) and that of subjects with BPH (2.1+/-0.6) ( P<0.01 in each case). The primary prostate cancer in six cases was visualised by [(11)C]acetate PET. However, the difference in the SUV between subjects aged > or =50 with normal prostate or with BPH and the patients with prostate cancer (1.9+/-0.6) was not statistically significant. There was also no significant difference in the E/L ratio between subjects aged > or =50 with normal prostate (0.98+/-0.04) or BPH (0.96+/-0.08) and patients with prostate cancer (1.02+/-0.12). In conclusion, a normal prostate exhibits age-related physiological accumulation of [(11)C]acetate. Careful interpretation of [(11)C]acetate PET images of prostate cancer is necessary because the SUV and the E/L ratio for the normal prostate and for BPH overlap significantly with those for prostate cancer.

Acetates↗