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ABSTRACT: Tumor hypoxia is well known to be radiation resistant. (18)F-fluoromisonidazole ((18)F-FMISO) PET has been used for noninvasive evaluation of hypoxia. Quantitative evaluation of (18)F-FMISO uptake is thus expected to play an important role in the planning of dose escalation radiotherapy. However, the reproducibility of (18)F-FMISO uptake has remained unclarified. We therefore investigated the reproducibility of tumor hypoxia by using quantitative analysis of (18)F-FMISO uptake. METHODS: Eleven patients with untreated head and neck cancer underwent 2 (18)F-FMISO PET/CT scans ((18)F-FMISO(1) and (18)F-FMISO(2)) with a 48-h interval prospectively. All images were acquired at 4 h after (18)F-FMISO injection for 10 min. The maximum standardized uptake (SUVmax), tumor-to-blood ratio (TBR), and tumor-to-muscle ratio (TMR) of (18)F-FMISO uptake were statistically compared between the 2 (18)F-FMISO scans by use of intraclass correlation coefficients (ICCs). The hypoxic volume was calculated as the area with a TBR of greater than or equal to 1.5 or the area with a TMR of greater than or equal to 1.25 to assess differences in hypoxic volume between the 2 (18)F-FMISO scans. The distances from the maximum uptake locations of the (18)F-FMISO(1) images to those of the (18)F-FMISO(2) images were measured to evaluate the locations of (18)F-FMISO uptake. RESULTS: The SUVmax (mean ± SD) for (18)F-FMISO(1) and (18)F-FMISO(2) was 3.16 ± 1.29 and 3.02 ± 1.12, respectively, with the difference between the 2 scans being 7.0% ± 4.6%. The TBRs for (18)F-FMISO(1) and (18)F-FMISO(2) were 2.98 ± 0.83 and 2.97 ± 0.64, respectively, with a difference of 9.9% ± 3.3%. The TMRs for (18)F-FMISO(1) and (18)F-FMISO(2) were 2.25 ± 0.71 and 2.19 ± 0.67, respectively, with a difference of 7.1% ± 5.3%. The ICCs for SUVmax, TBR, and TMR were 0.959, 0.913, and 0.965, respectively. The difference in hypoxic volume based on TBR was 1.8 ± 1.8 mL, and the difference in hypoxic volume based on TMR was 0.9 ± 1.3 mL, with ICCs of 0.986 and 0.996, respectively. The maximum uptake locations of the (18)F-FMISO(1) images were different from those of the (18)F-FMISO(2) images and were within the full width at half maximum of the PET/CT scanner, except in 1 case. CONCLUSION: The values for (18)F-FMISO PET uptake and hypoxic volume in head and neck tumors between the 2 (18)F-FMISO scans were highly reproducible. Such high reproducibility of tumor hypoxia is promising for accurate radiation planning.
Journal of Nuclear Medicine 01/2013; · 6.38 Impact Factor
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Toshiki Takei,
Tohru Shiga,
Yuichi Morimoto,
Wataru Takeuchi,
Kikuo Umegaki,
Kazuki Matsuzaki, Shozo Okamoto,
Keiichi Magota,
Toshihiro Hara,
Satoshi Fukuda,
Nagara Tamaki
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ABSTRACT: OBJECTIVES: Our research group developed new PET scanner with semiconductor detectors for high spatial resolution with low scatter noise. On head and neck cancer (HNC) surgery, FDG-PET may often provide false-positive findings in cervical node involvements. Accordingly, we assessed diagnostic accuracy using this new scanner in the HNC patients as compared with the conventional lutetium oxyorthosilicate (LSO) PET. METHODS: We prospectively studied FDG imaging in 35 HNC patients by both semiconductor PET and LSO-PET. At 60 min after (18)F-FDG injection, two PET scans were obtained using both scanners consecutively and in random order. Two nuclear medicine specialists scored FDG abnormalities using 5 point scale system for receiver operating characteristic (ROC) curve analysis. RESULTS: 63 suspected of metastatic or recurrent lesions were evaluated and correlated by the final confirmation by pathological findings or clinical courses (malignant 26/benign 37). Semiconductor PET showed sensitivity of 92.3 % (24/26), specificity of 51.4 % (19/37), and accuracy of 68.2 % (43/63), while LSO-PET showed sensitivity of 84.6 % (22/26), specificity of 16.2 %(6/37), and accuracy of 44.4 % (28/63), respectively. Especially, semiconductor PET accurately diagnosed as true negative in the 13 of 14 lesions only detected by LSO-PET. ROC analyses revealed the diagnostic superiority of semiconductor PET from location of- and area under curve particularly in the study of small (≤10 mm) lesions. CONCLUSION: A new novel semiconductor PET scanner can increase diagnostic accuracy with reduction in false positive findings in the HNC patients mainly due to higher spatial resolution and lower noise than the LSO-PET. This new technology can lead to more accurate diagnosis and the more optimal therapeutic tactics in head and neck surgery.
Annals of Nuclear Medicine 11/2012; · 1.50 Impact Factor
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Koichi Yasuda,
Rikiya Onimaru, Shozo Okamoto,
Tohru Shiga,
Norio Katoh,
Kazuhiko Tsuchiya,
Ryusuke Suzuki,
Wataru Takeuchi,
Yuji Kuge,
Nagara Tamaki,
Hiroki Shirato
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ABSTRACT: PURPOSE: The impact of a new type of positron emission tomography (New PET) with semiconductor detectors using (18)F-labeled fluoromisonidazole (FMISO)-guided intensity modulated radiation therapy (IMRT) was compared with a state-of-the-art PET/computed tomography (PET/CT) system in nasopharyngeal cancer (NPC) patients. METHODS AND MATERIALS: Twenty-four patients with non-NPC malignant tumors (control group) and 16 patients with NPC were subjected to FMISO-PET. The threshold of the tumor-to-muscle (T/M) ratio in each PET scan was calculated. The hypoxic volume within the gross tumor volume (GTVh) was determined using each PET ((NewPET)GTVh and (PET/CT)GTVh, respectively). Dose escalation IMRT plans prescribing 84 Gy to each GTVh were carried out. RESULTS: The threshold of the T/M ratio was 1.35 for New PET and 1.23 for PET/CT. The mean volume of (NewPET)GTVh was significantly smaller than that of (PET/CT)GTVh (1.5 ± 1.6 cc vs 4.7 ± 4.6 cc, respectively; P=.0020). The dose escalation IMRT plans using New PET were superior in dose distribution to those using PET/CT. Dose escalation was possible in all 10 New PET-guided plans but not in 1 PET/CT-guided plan, because the threshold dose to the brainstem was exceeded. CONCLUSIONS: New PET was found to be useful for accurate dose escalation in FMISO-guided IMRT for patients with NPC.
International journal of radiation oncology, biology, physics 05/2012; · 4.59 Impact Factor
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ABSTRACT: ObjectiveThe purpose of this study was to investigate whether improvement of regional inflammatory findings in knee joints of rheumatoid
arthritis (RA) could be detected by positron-emission tomography (PET) using 18F-Fluorodeoxyglucose (FDG) after acupuncture treatments, as well as improvement of systemic inflammatory markers.
MethodsSix RA patients (all female, 61±12years old) received 10 acupuncture treatments in 2months, to 11 traditional acupuncture
points around a knee joint considered effective on RA. A visual analogue scale (VAS) for intensity of pain, knee joint range
of motion (ROM), face scale for patient mood, and modified health assessment questionnaire (MHAQ) for disability of daily
activities were assessed just before and after acupuncture. Maximum standardized uptake value (SUVmax) and the volume with SUV more than 1.0 [Volume(SUV>1)] on FDG–PET images as well as erythrocyte sedimentation rate (ESR)
and C-reactive protein (CRP) levels were also measured before and after the treatments.
ResultsVAS, ROM, face scale and MHAQ improved in all patients and significantly after acupuncture, but no significant change was
detected in ESR, CRP, SUVmax, or Volume(SUV>1).
ConclusionsAcupuncture relieves symptom, remedies physical function, and improves quality of life in RA patients, but may have no or
very limited anti-inflammatory effect systemically. The regional effects of acupuncture are unlikely to be induced through
reduction of regional inflammation. We believe this clinical study is the first step for elucidating therapeutic mechanisms
of acupuncture, which must be important for the rational use and further development of acupuncture.
Annals of Nuclear Medicine 04/2012; 23(3):311-316. · 1.50 Impact Factor
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ABSTRACT: (11)C-Methionine positron emission tomography (MET-PET) has been used to distinguish brain tumor recurrence from radiation necrosis. Because the spatial resolution of conventional PET scanners is low, partial volume effect (PVE) may decrease the detectability of small tumor recurrence. The aim of this study is to investigate the diagnostic value of MET-PET upon semiquantitative analyses in particular PVE-affected small lesions.
First, we performed a phantom experiment to investigate what size lesion is affected by PVE. This study included 29 patients (33 lesions) suspected of recurrent brain tumors by magnetic resonance imaging (MRI) after radiation therapy. All of them received MET-PET. Semiquantitative analysis was performed using maximum standardized uptake value (SUVmax) and lesion-versus-normal ratio (L/N ratio). ROC analysis was also assessed about the diagnostic value of MET-PET.
From the result of the phantom experiment, lesions smaller than 20 mm in brain mode or smaller than 30 mm in whole-body mode were defined as PVE-affected lesions. Histological analysis or clinical follow-up confirmed the diagnosis of tumor recurrence in 22 lesions, and radiation necrosis in 11 lesions. L/N ratios of recurrence and necrosis for overall lesions were 1.98 ± 0.62 and 1.27 ± 0.28, respectively (p < 0.01). In the PVE-affected lesions, L/N ratio for recurrence (1.72 ± 0.44) was also significantly higher than that for necrosis (1.20 ± 0.11) (p < 0.01). On the ROC analysis for the PVE-affected lesions, the area under the curve for L/N ratio (0.897) was significantly higher than that for SUVmax (0.718) (p < 0.05). These areas under the curve were almost equal to that of overall lesions for L/N ratio (0.886) and for SUVmax (0.738).
Semiquantitative analysis of MET provided high diagnostic value even for PVE-affected small lesions. MET-PET enables early diagnosis of recurrence of brain tumor in the follow-up after the radiation therapy.
Annals of Nuclear Medicine 12/2010; 25(3):213-20. · 1.50 Impact Factor
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ABSTRACT: The purpose of this study was to investigate whether improvement of regional inflammatory findings in knee joints of rheumatoid arthritis (RA) could be detected by positron-emission tomography (PET) using (18)F-Fluorodeoxyglucose (FDG) after acupuncture treatments, as well as improvement of systemic inflammatory markers.
Six RA patients (all female, 61 +/- 12 years old) received 10 acupuncture treatments in 2 months, to 11 traditional acupuncture points around a knee joint considered effective on RA. A visual analogue scale (VAS) for intensity of pain, knee joint range of motion (ROM), face scale for patient mood, and modified health assessment questionnaire (MHAQ) for disability of daily activities were assessed just before and after acupuncture. Maximum standardized uptake value (SUV(max)) and the volume with SUV more than 1.0 [Volume(SUV > 1)] on FDG-PET images as well as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were also measured before and after the treatments.
VAS, ROM, face scale and MHAQ improved in all patients and significantly after acupuncture, but no significant change was detected in ESR, CRP, SUV(max), or Volume(SUV > 1).
Acupuncture relieves symptom, remedies physical function, and improves quality of life in RA patients, but may have no or very limited anti-inflammatory effect systemically. The regional effects of acupuncture are unlikely to be induced through reduction of regional inflammation. We believe this clinical study is the first step for elucidating therapeutic mechanisms of acupuncture, which must be important for the rational use and further development of acupuncture.
Annals of Nuclear Medicine 04/2009; 23(3):311-6. · 1.50 Impact Factor
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ABSTRACT: A 55-year-old woman underwent radioiodine therapy for papillary carcinoma of the thyroid. Post-therapeutic I-131 scan revealed radioiodine uptake in the pelvic region and in the thyroid bed. CT revealed a huge mass connected to the uterus. The tumor was operated on and histologically proven to be a leiomyoma of the uterus. Some physiological conditions or nonthyroidal diseases can cause false positives in patients with postoperative thyroid cancer. We suggest that uterine leiomyoma might be added to the pitfall list, although the mechanism of I-131 uptake remains unclear.
Clinical nuclear medicine 04/2009; 34(3):180-1. · 3.92 Impact Factor
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ABSTRACT: The clinical value of 13N-ammonia PET is reviewed by using previously published articles with significant evidence level. This meta-analysis indicated that due to excellent myocardial blood flow images, 13N-ammonia PET permits better diagnostic accuracy of ischemic heart disease and viability assessment than myocardial perfusion SPECT. Furthermore, quantitative assessment of myocardial blood flow (MBF) in absolute units can be performed using 13N-ammonia PET. MBF measurement is a useful tool to evaluate cardiac pathophysiology and monitor therapeutic effects of cardiac disease and cardiovascular risk factors.
Kaku igaku. The Japanese journal of nuclear medicine 12/2007; 44(4):365-72.
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ABSTRACT: Iodine-131 metaiodobenzylguanidine ((131)I-MIBG) therapy is an effective treatment for patients with malignant paraganglioma for which surgical resection is not indicated. We performed high-dose (131)I-MIBG therapy on two patients with malignant paraganglioma and multiple bone metastases. The bone metastases were diagnosed by magnetic resonance imaging (MRI). Metastatic bone lesions were evaluated by whole-body (131)I-MIBG imaging and bone scintigraphy. Whole-body (131)I-MIBG imaging showed extensive metastatic bone lesions, whereas conventional bone scintigraphy did not. There was a remarkable discrepancy between (131)I-MIBG imaging and bone scintigraphy in the diagnosis of metastatic bone lesions of malignant paraganglioma in our two patients. High-dose (131)I-MIBG imaging may detect early stages of bone metastases, compared with bone scintigraphy, in patients with malignant paraganglioma.
Annals of Nuclear Medicine 08/2007; 21(5):307-10. · 1.50 Impact Factor
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ABSTRACT: In an attempt to identify a cohort with a high risk of suffering a fracture of the contralateral hip (second hip fracture), we assessed patients who had suffered hip fracture. A total of 714 patients (130 men and 584 women) were prospectively followed to determine those who suffered a second hip fracture. Pathologic hip fractures and fractures that emerged from high-energy trauma were excluded from the analysis. Age, gender, Singh Index (SI), fracture type, cognitive impairment, and comorbid medical conditions were investigated as medical predictors. The 714 patients were observed for 1,579.5 person-years (mean: 2.4+/-1.4 years per patient). During the observation period, 45 second hip fractures were identified (bilateral group), giving an overall incidence of 0.029 per person-year. The annual incidence rate declined linearly from the occasion of the initial fracture. Furthermore, the second hip fracture tended to occur increasingly within 8 months after the initial hip fracture. The second hip fracture was of the same type (trochanteric or cervical) in 79% of the trochanteric and 71% of the cervical fractures. There was no significant difference in the incidence of second hip fracture by gender or age. In addition, there was no significant difference in the distribution of SI grades of the unfractured hip at the initial hip fracture between the 669 patients who had not suffered a second hip fracture (unilateral group) and the bilateral group. Cox proportional hazard regression analysis revealed that increased risk of a second hip fracture was associated with senile dementia and Parkinson's disease. We concluded that careful follow-up of hip fracture patients associated with senile dementia and Parkinson's disease might effectively prevent the incidence of a second hip fracture.
Osteoporosis International 11/2005; 16(10):1239-46. · 4.58 Impact Factor
