Table tennis for patients with Parkinson's disease: A single-center, prospective pilot study

INTRODUCTION

Table tennis is a popular sport worldwide. However, no study has examined whether it is an effective exercise for patients with Parkinson's disease (PD). The efficacy and safety of table tennis exercise for PD patients was examined.

METHODS

This 6-month prospective study investigated if our table tennis exercise program could improve parkinsonian motor symptoms, cognition and psychiatric symptoms. Twelve PD patients with Hoehn & Yahr stage ≤4 were recruited. Patients participated in a 6-hour exercise session once weekly. All patients were assessed with the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) parts I-IV, Montreal Cognitive Assessment (MoCA), Frontal Assessment Battery (FAB), Self-Rating Depression Scale (SDS), and Starkstein Apathy Scale (SAS) at baseline, 3 months, and 6 months.

RESULTS

Nine of 12 PD patients were analyzed, except for three patients for which data was missing. MDS-UPDRS parts II and III were improved at 3 months (median -4.0, p = 0.012 and median -10.0, p = 0.012) and 6 months (median -7.0, p = 0.015 and median -12.0, p = 0.008), whereas MDS-UPDRS total parts I scores and total IV scores, MoCA, FAB, SDS, and SAS were unchanged. Adverse events included fall and backache in one patient each.

CONCLUSION

A table tennis exercise program is relatively safe and may improve activities of daily living and motor symptoms in patients with PD.

ICRP Publication 140: Radiological Protection in Therapy with Radiopharmaceuticals

Radiopharmaceuticals are increasingly used for the treatment of various cancers with novel radionuclides, compounds, tracer molecules, and administration techniques. The goal of radiation therapy, including therapy with radiopharmaceuticals, is to optimise the relationship between tumour control probability and potential complications in normal organs and tissues. Essential to this optimisation is the ability to quantify the radiation doses delivered to both tumours and normal tissues. This publication provides an overview of therapeutic procedures and a framework for calculating radiation doses for various treatment approaches. In radiopharmaceutical therapy, the absorbed dose to an organ or tissue is governed by radiopharmaceutical uptake, retention in and clearance from the various organs and tissues of the body, together with radionuclide physical half-life. Biokinetic parameters are determined by direct measurements made using techniques that vary in complexity. For treatment planning, absorbed dose calculations are usually performed prior to therapy using a trace-labelled diagnostic administration, or retrospective dosimetry may be performed on the basis of the activity already administered following each therapeutic administration. Uncertainty analyses provide additional information about sources of bias and random variation and their magnitudes; these analyses show the reliability and quality of absorbed dose calculations. Effective dose can provide an approximate measure of lifetime risk of detriment attributable to the stochastic effects of radiation exposure, principally cancer, but effective dose does not predict future cancer incidence for an individual and does not apply to short-term deterministic effects associated with radiopharmaceutical therapy. Accident prevention in radiation therapy should be an integral part of the design of facilities, equipment, and administration procedures. Minimisation of staff exposures includes consideration of equipment design, proper shielding and handling of sources, and personal protective equipment and tools, as well as education and training to promote awareness and engagement in radiological protection. The decision to hold or release a patient after radiopharmaceutical therapy should account for potential radiation dose to members of the public and carers that may result from residual radioactivity in the patient. In these situations, specific radiological protection guidance should be provided to patients and carers.

Association between health risks and frailty in relation to the degree of housing damage among elderly survivors of the great East Japan earthquake

Background

Many survivors of the Great East Japan Earthquake that occurred in 2011 were at risk of deteriorating health, especially elderly people living in disaster-stricken areas. The objectives of this prospective study were: a) to clarify the different lifestyle and psychosocial factors associated with frailty by sex among the non-disabled elderly survivors, and b) to describe the differences in characteristics stratified by the degree of disaster-related housing damage.

Methods

We followed 2261 Japanese survivors aged ≥65 years (45.3% male; mean age, 71.7 years) without disability or frailty who completed a self-administered questionnaire at baseline. All participants completed a baseline questionnaire in 2011 and at least one identical follow-up questionnaire between 2012 and 2015 regarding lifestyle (smoking status, alcohol intake, physical activity, sedentary lifestyle, and dietary intake) and psychosocial factors (self-rated health, standard of living, psychological distress, and social networks). Frailty was defined as a score of ≥5 on the Kihon Checklist, which is used by the Japanese government to certify the need for long-term care insurance. Adjusted odds ratios and 95% confidence intervals with frailty as the dichotomous dependent variable and health factors as the independent variables were calculated using a multilevel model for repeated measures by sex, followed by stratification analyses by the degree of housing damage.

Results

Over the 4-year study period, 510 participants (22.6%) developed frailty. In the post-disaster setting, many of the psychosocial factors remained more prevalent 4 years later among survivors with extensive housing damage. The presence of risk factors regarding the development of frailty differed by the degree of housing damage. Among men, psychological distress, in parallel with a poor social network, was related to frailty among only the participants with extensive housing damage and those living in temporary housing, whereas among women, worsening psychological distress was associated only with no damage and no displaced survivors. Among women with extensive damage and displacement, health outcomes such as overweight and diabetes and poor social networks were strongly related to frailty.

Conclusions

Lifestyle and psychosocial factors associated with the risk of frailty differ by sex and the degree of housing damage.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0828-x) contains supplementary material, which is available to authorized users.

Radiological protection in ion beam radiotherapy: practical guidance for clinical use of new technology

Recently introduced technologies in radiotherapy have significantly improved the clinical outcome for patients. Ion beam radiotherapy, involving proton and carbon ion beams, provides excellent dose distributions in targeted tumours, with reduced doses to the surrounding normal tissues. However, careful treatment planning is required in order to maximise the treatment efficiency and minimise the dose to normal tissues. Radiation exposure from secondary neutrons and photons, particle fragments, and photons from activated materials should also be considered for radiological protection of the patient and medical staff. Appropriate maintenance is needed for the equipment and air in the treatment room, which may be activated by the particle beam and its secondary radiation. This new treatment requires complex procedures and careful adjustment of parameters for each patient. Therefore, education and training for the personnel involved in the procedure are essential for both effective treatment and patient protection. The International Commission on Radiological Protection (ICRP) has provided recommendations for radiological protection in ion beam radiotherapy in Publication 127 Medical staff should be aware of the possible risks resulting from inappropriate use and control of the equipment. They should also consider the necessary procedures for patient protection when new technologies are introduced into clinical practice.

ICRP Publication 127: Radiological Protection in Ion Beam Radiotherapy

The goal of external-beam radiotherapy is to provide precise dose localisation in the treatment volume of the target with minimal damage to the surrounding normal tissue. Ion beams, such as protons and carbon ions, provide excellent dose distributions due primarily to their finite range, allowing a significant reduction of undesired exposure of normal tissue. Careful treatment planning is required for the given type and localisation of the tumour to be treated in order to maximise treatment efficiency and minimise the dose to normal tissue. Radiation exposure in out-of-field volumes arises from secondary neutrons and photons, particle fragments, and photons from activated materials. These unavoidable doses should be considered from the standpoint of radiological protection of the patient. Radiological protection of medical staff at ion beam radiotherapy facilities requires special attention. Appropriate management and control are required for the therapeutic equipment and the air in the treatment room that can be activated by the particle beam and its secondaries. Radiological protection and safety management should always conform with regulatory requirements. The current regulations for occupational exposures in photon radiotherapy are applicable to ion beam radiotherapy with protons or carbon ions. However, ion beam radiotherapy requires a more complex treatment system than conventional radiotherapy, and appropriate training of staff and suitable quality assurance programmes are recommended to avoid possible accidental exposure of patients, to minimise unnecessary doses to normal tissue, and to minimise radiation exposure of staff.

Osteoconductivity of thermal-sprayed silver-containing hydroxyapatite coating in the rat tibia

A silver-containing hydroxyapatite (Ag-HA) coating has been developed using thermal spraying technology. We evaluated the osteoconductivity of this coating on titanium (Ti) implants in rat tibiae in relation to bacterial infection in joint replacement.

At 12 weeks, the mean affinity indices of bone formation of a Ti, an HA, a 3%Ag-HA and a 50%Ag-HA coating were 97.3%, 84.9%, 81.0% and 40.5%, respectively. The mean affinity indices of bone contact of these four coatings were 18.8%, 83.7%, 77.2% and 40.5%, respectively. The indices of bone formation and bone contact around the implant of the 3%Ag-HA coating were similar to those of the HA coating, and no significant differences were found between them (bone formation, p = 0.99; bone contact, p = 0.957). However, inhibition of bone formation was observed with the 50%Ag-HA coating.

These results indicate that the 3%Ag-HA coating has low toxicity and good osteoconductivity, and that the effect of silver toxicity on osteoconductivity depends on the dose.

Neuroprotective effect of chronic lithium treatment against hypoxia in specific brain regions with upregulation of cAMP response element binding protein and brain-derived neurotrophic factor but not nerve growth factor: comparison with acute lithium treatment

OBJECTIVES

We evaluated the neuroprotective effect of chronically or acutely administered lithium against hypoxia in several brain regions. Furthermore, we investigated the contribution of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and cAMP response element binding protein (CREB) to the neuroprotective effect of lithium.

METHODS

Brain slices were prepared from rats that had been treated chronically or acutely with lithium. The cerebral glucose metabolic rate (CMRglc) before and after hypoxia loading to brain slices was measured using the dynamic positron autoradiography technique with [(18)F]2-fluoro-2-deoxy-D-glucose. The changes of expression of proteins were investigated using Western blot analysis.

RESULTS

Before hypoxia loading, the CMRglc did not differ between the lithium-treated and untreated groups. After hypoxia loading, the CMRglc of the untreated group was significantly lower than that before hypoxia loading. However, the CMRglc of the chronic lithium treatment group recovered in the frontal cortex, caudate putamen, hippocampus and cerebellum, but not in the thalamus. In contrast, the CMRglc of the acute lithium treatment group did not recover in any analyzed brain regions. After chronic lithium treatment, the levels of expression of BDNF and phospho-CREB were higher than those of untreated rats in the frontal cortex, but not in the thalamus. However, the expression of NGF did not change in the frontal cortex and thalamus.

CONCLUSIONS

These results demonstrated that lithium was neuroprotective against hypoxia only after chronic treatment and only in specific brain regions, and that CREB and BDNF might contribute to this effect.

Abnormal pontine activation in pathological laughing as shown by functional magnetic resonance imaging

To explore the aetiology of pathological laughing, a 65-year-old woman with pathological laughing was examined by 3-T functional magnetic resonance imaging (fMRI) before and after treatment with drugs. Here, we report that the patient consistently showed exaggerated pontine activation during the performance of three tasks before treatment, whereas abnormal pontine activation was no longer found after successful treatment with the selective serotonin reuptake inhibitor, paroxetine. Our findings in this first fMRI study of pathological laughing suggest that serotonergic replacement decreases the aberrant activity in a circuit that involves the pons.

Region-specific induction of hypoxic tolerance by expression of stress proteins and antioxidant enzymes

We examined the induction of hypoxic tolerance after hypoxic preconditioning in the frontal cortex, caudate putamen and thalamus using the dynamic positron autoradiography technique and [18F]2-fluoro-2-deoxy-D-glucose with rat brain slices. Hypoxic tolerance induction was confirmed in the frontal cortex, but not in the caudate putamen and thalamus. Next, we compared the gene expression in the frontal cortex and caudate putamen using the ATLAS Rat Stress Array, and found that the expression of 150-kDa oxygen-regulated protein and mitochondrial heat shock protein 70 as stress proteins, and copper-zinc-containing superoxide dismutase and manganese-containing superoxide dismutase as antioxidant enzymes was elevated only in the frontal cortex. These results suggest that the induction of hypoxic tolerance after hypoxic preconditioning is region-specific, and stress proteins and antioxidant enzymes participate in this phenomenon.

Neural substrates participating in acquisition of facial familiarity: an fMRI study

The amygdala is related to recognition of faces and emotions, and functional magnetic resonance imaging (fMRI) studies have reported that the amygdala is habituated over time with repetition of facial stimuli. When subjects are presented repeatedly with unfamiliar faces, they come to gradually recognize the unfamiliar faces as familiar. To investigate the brain areas participating in the acquisition of familiarity to repeatedly presented unfamiliar faces, we conducted an fMRI study in 16 healthy subjects. During the task periods, the subjects were instructed to see presented unfamiliar faces repeatedly and to judge whether the face was male or female or whether the face had emotional valences. The experiment consisted of nine sessions. To clarify the brain areas that showed increasing or decreasing activation as the experimental session proceeded, we analyzed the fMRI data using specified linear covariates in the face recognition task from the first session to the ninth session. Imaging data were investigated on a voxel-by-voxel basis for single-group analysis according to the random effect model using Statistical Parametric Mapping. The bilateral posterior cingulate cortices showed significant increases in activity as the experimental sessions proceeded, while the activation in the right amygdala and the left medial fusiform gyrus decreased. Thus, the posterior cingulate cortex may play an important role in the acquisition of facial familiarity.

Micro-X-ray diffraction observation of nickel–titanium orthodontic wires in simulated oral environment

A micro-X-ray diffraction (micro-XRD) technique has been employed to determine the phases in two superelastic nickel-titanium orthodontic wires that exhibit shape memory in the oral environment and one superelastic nickel-titanium wire that does not exhibit shape memory in vivo. The micro-XRD analyses were performed over the clinically relevant temperature range of 0-55 degrees C, which corresponds to the ingestion of cold and hot liquids, and both straight and bent (135 degrees ) test samples were analyzed. The results showed that for straight (as-received) test samples, the rhombohedral phase (R-phase) was definitely present in one shape memory wire product and perhaps in the other shape memory wire product, but was apparently absent in the superelastic wire product that did not display shape memory. Martensite was observed in all three wire products after bending. Phase transformations occurred with temperature changes simulating the oral environment for straight test samples of the two shape memory wires, but the micro-XRD pattern changed minimally with temperature for straight test samples of the superelastic wire and for bent test samples of all three wire products. The phase transformations revealed by micro-XRD were consistent with results recently found by temperature-modulated differential scanning calorimetry.

Association between the expression of inducible nitric oxide synthase by chondrocytes and its nitric oxide-generating activity in adjuvant arthritis in rats

Inducible nitric oxide synthase (iNOS) is one of the clinical targets in rheumatoid arthritis. Synoviocytes, macrophages, and chondrocytes in the joints of patients with rheumatoid arthritis appear to express iNOS, but the contribution of iNOS molecules to rheumatoid arthritis is not yet clear. This study used adjuvant-induced arthritis in rats as a model to examine the association between the iNOS expression and its activity in rheumatoid arthritis. In adjuvant-injected rats, arthritic changes in the paw were first observed between days 10 and 12. NO-generation activity was precisely determined by combining an electron spin resonance/nitric oxide (NO)-trapping method with the method of standard addition using an NO generator, and we found that the activity in the joint samples was extremely high on day 10. The administration of S-(2-aminoethyl)isothiourea, a selective iNOS inhibitor, from day 0 to day 10, effectively reduced the paw swelling. Immunohistological studies showed that chondrocytes expressed iNOS on days 7-14 and that nitrotyrosine residues, a footprint of NO generation, were produced on day 10. This indicates that NO generation by iNOS induced in chondrocytes is a key event in the induction of adjuvant arthritis.

Differential amygdala response during facial recognition in patients with schizophrenia: an fMRI study

Human lesion or neuroimaging studies suggest that amygdala is involved in facial emotion recognition. Although impairments in recognition of facial and/or emotional expression have been reported in schizophrenia, there are few neuroimaging studies that have examined differential brain activation during facial recognition between patients with schizophrenia and normal controls. To investigate amygdala responses during facial recognition in schizophrenia, we conducted a functional magnetic resonance imaging (fMRI) study with 12 right-handed medicated patients with schizophrenia and 12 age- and sex-matched healthy controls. The experiment task was a type of emotional intensity judgment task. During the task period, subjects were asked to view happy (or angry/disgusting/sad) and neutral faces simultaneously presented every 3 s and to judge which face was more emotional (positive or negative face discrimination). Imaging data were investigated in voxel-by-voxel basis for single-group analysis and for between-group analysis according to the random effect model using Statistical Parametric Mapping (SPM). No significant difference in task accuracy was found between the schizophrenic and control groups. Positive face discrimination activated the bilateral amygdalae of both controls and schizophrenics, with more prominent activation of the right amygdala shown in the schizophrenic group. Negative face discrimination activated the bilateral amygdalae in the schizophrenic group whereas the right amygdala alone in the control group, although no significant group difference was found. Exaggerated amygdala activation during emotional intensity judgment found in the schizophrenic patients may reflect impaired gating of sensory input containing emotion.

Greater resistance and lower contribution of free radicals to hypoxic neurotoxicity in immature rat brain compared to adult brain as revealed by dynamic changes in glucose metabolism

Seven-day-old rat brain slices were incubated at 36C in oxygenated Krebs-Ringer solution containing [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG), and serial two-dimensional time-resolved images of [(18)F]FDG uptake by the slices were obtained. The Gjedde-Patlak graphical method was applied to the image data, and the duration limit of hypoxia loading that allowed recovery of the fractional rate constant (k3*) of [(18)F]FDG (proportional to the cerebral glucose metabolic rate) after hypoxia loading to the unloaded control level was 50 min, and MK-801 as an N-methyl-D-aspartate antagonist had neuroprotective effects, but PBN as a free radical scavenger was ineffective. In our previous study in adult (7-week-old) rat brains [Murata et al., Exp Neurol 2000, 164:269-279], the limit of the hypoxia loading time was 20 min, and both MK-801 and PBN were effective. In the immature rat brains, the ratio of aerobic glucose metabolism to the total glucose metabolism was low compared with the adult rat brains, suggesting only a slight involvement of free radicals in hypoxic neurotoxicity. These data suggest that the higher resistance of immature brains to hypoxia compared to that of adult brains is attributable to a lower involvement of free radicals due to a lower aerobic glucose metabolic rate.

Retention mechanism of hypoxia selective nuclear imaging/radiotherapeutic agent cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) in tumor cells

The retention mechanism of the novel imaging/radiotherapeutic agent, Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) in tumor cells was clarified in comparison with that in normal tissue in vitro. With Cu-ATSM and reversed phase HPLC analysis, the reductive metabolism of Cu-ATSM in subcellular fractions obtained from Ehrlich ascites tumor cells was examined. As a reference, mouse brain was used. To determine the contribution of enzymes in the retention mechanisms, and specific inhibitor studies were performed. In subcellular fractions of tumor cells, Cu-ATSM was reduced mainly in the microsome/cytosol fraction rather than in the mitochondria. This finding was completely different from that found in normal brain cells. The reduction process in the microsome/cytosol was heat-sensitive and enhanced by adding exogenous NAD(P)H, an indication of enzymatic reduction of Cu-ATSM in tumor cells. Among the known bioreductive enzymes, NADH-cytochrome b5 reductase and NADPH-cytochrome P450 reductase in microsome played a major role in the reductive retention of Cu-ATSM in tumors. This enzymatic reduction was enhanced by the induction of hypoxia. Radiocopper labeled Cu-ATSM provides useful information for the detection of hypoxia as well as the microsomal bioreductive enzyme expression in tumor.

Neural interaction of the amygdala with the prefrontal and temporal cortices in the processing of facial expressions as revealed by fMRI

Some involvement of the human amygdala in the processing of facial expressions has been investigated in neuroimaging studies, although the neural mechanisms underlying motivated or emotional behavior in response to facial stimuli are not yet fully understood. We investigated, using functional magnetic resonance imaging (fMRI) and healthy volunteers, how the amygdala interacts with other cortical regions while subjects are judging the sex of faces with negative, positive, or neutral emotion. The data were analyzed by a subtractive method, then, to clarify possible interaction among regions within the brain, several kinds of analysis (i.e., a correlation analysis, a psychophysiological interaction analysis and a structural equation modeling) were performed. Overall, significant activation was observed in the bilateral fusiform gyrus, medial temporal lobe, prefrontal cortex, and the right parietal lobe during the task. The results of subtraction between the conditions showed that the left amygdala, right orbitofrontal cortex, and temporal cortices were predominantly involved in the processing of the negative expressions. The right angular gyrus was involved in the processing of the positive expressions when the negative condition was subtracted from the positive condition. The correlation analysis showed that activity in the left amygdala positively correlated with activity in the left prefrontal cortex under the negative minus neutral subtraction condition. The psychophysiological interaction revealed that the neural responses in the left amygdala and the right prefrontal cortex underwent the condition-specific changes between the negative and positive face conditions. The right amygdaloid activity also had an interactive effect with activity in the right hippocampus and middle temporal gyrus. These results may suggest that the left and right amygdalae play a differential role in effective processing of facial expressions in collaboration with other cortical or subcortical regions, with the left being related with the bilateral prefrontal cortex, and the right with the right temporal lobe.

Blood volume of gliomas determined by double-echo dynamic perfusion-weighted MR imaging: a preliminary study

BACKGROUND AND PURPOSE

After bolus injection, gadopentetate dimeglumine causes a T2* rate change in permeable tissue that is contaminated by the T1 shortening effect due to the leakage of contrast agent. Therefore, tumor vascularity as reported in previous single-echo perfusion-weighted MR imaging studies has been underestimated. Our aim was to quantitatively and qualitatively evaluate the degree of blood volume of glioblastoma multiformes (GBMs) underestimated by this T1 shortening effect.

METHODS

We used double-echo dynamic MR imaging after a bolus injection of gadopentetate dimeglumine (double-echo perfusion-weighted MR imaging) to simultaneously determine tumor blood volume without (V(T1U)) and with (V(T1C)) T1 shortening correction. MR imaging was performed in five consecutive patients with GBMs. The ratios of V(T1U) and V(T1C) were calculated and compared by means of quantitative analysis. The degree of tumor blood volume as determined by V(T1U) and V(T1C) maps were qualitatively compared using a three-point scale.

RESULTS

All GBMs showed contrast enhancement on postcontrast T1-weighted images. In all subjects, the values of V(T1U) were significantly lower than those of V(T1C) (mean +/- SD, 2.05 +/- 1.01 vs. 3.62 +/- 1.40, respectively [P <.05]), indicating that tumor blood volume obtained by double-echo perfusion-weighted MR imaging was significantly higher than that by single-echo imaging. In the qualitative analysis, tumor blood volume on the V(T1U) map was less conspicuous than that on the V(T1C) map.

CONCLUSION

Careful attention should be paid to the underestimation of tumor blood volume resulting from T1 shortening effects when using single-echo perfusion-weighted MR imaging. Double-echo imaging may be more suitable for the analysis of blood volume in GBMs.

Attention to emotion modulates fMRI activity in human right superior temporal sulcus

A parallel neural network has been proposed for processing various types of information conveyed by faces including emotion. Using functional magnetic resonance imaging (fMRI), we tested the effect of the explicit attention to the emotional expression of the faces on the neuronal activity of the face-responsive regions. Delayed match to sample procedure was adopted. Subjects were required to match the visually presented pictures with regard to the contour of the face pictures, facial identity, and emotional expressions by valence (happy and fearful expressions) and arousal (fearful and sad expressions). Contour matching of the non-face scrambled pictures was used as a control condition. The face-responsive regions that responded more to faces than to non-face stimuli were the bilateral lateral fusiform gyrus (LFG), the right superior temporal sulcus (STS), and the bilateral intraparietal sulcus (IPS). In these regions, general attention to the face enhanced the activities of the bilateral LFG, the right STS, and the left IPS compared with attention to the contour of the facial image. Selective attention to facial emotion specifically enhanced the activity of the right STS compared with attention to the face per se. The results suggest that the right STS region plays a special role in facial emotion recognition within distributed face-processing systems. This finding may support the notion that the STS is involved in social perception.

Myocardial FDG-PET examination during fasting and glucose loading states by means of a one-day protocol

We propose a new method to measure the myocardial FDG uptake during fasting and glucose loading in one day, a myocardial FDG-PET one-day protocol, with both 2- and 3-dimensional data acquisition (2D and 3D) without background activity subtraction. To confirm it, we evaluated the effect of scatter correction in the 2D and 3D modes of a PET scanner both in phantom and patient studies. In the phantom study, we used a cardiac phantom with six divided chambers and two cylindrical phantoms placed as the activity outside the field of view. Each chamber was filled with a different concentration of F- 18 solution. Regions of interest (ROI) were placed on a polar map generated from reconstructed images and were compared to the concentration of the solution in each chamber in both 2D and 3D. In the patient study, 10 non-diabetic patients with coronary artery disease were studied. Each patient received a myocardial FDG study during fasting (F) and glucose loading (L). L images with background subtraction (Lsub(+)) and without background subtraction (Lsub(-)) were compared by polar map analysis. The ROI counts for the true activity in 2D and 3D demonstrated a linear relationship, and quite similar slopes were observed (0.72 in 2D, 0.69 in 3D). The background fraction in Lsub(-) was 3.59+/-1.83%. There were significant differences between Lsub(-) or Lsub(+) and F in both normal and ischemic myocardium. Scatter correction was successfully performed in both 2D and 3D modes. Background activity is thought to be negligible and this proposed method is simple touse in measuring the myocardial FDG uptake in one day.

FDG PET for evaluating the change of glucose metabolism in prostate cancer after androgen ablation

In the clinical study of prostate cancer, the effect of androgen ablation on glucose metabolism in cancer tissue has not been elucidated. The purpose of this study was to investigate the change in glucose utilization due to endocrine therapy for prostate adenocarcinoma. Ten patients with histologically proven prostate cancer were prospectively investigated with (18)F-fluorodeoxyglucose and positron emission tomography (FDG PET) prior to and after the initiation of endocrine therapy. FDG uptake was calculated to measure glucose utilization in cancer tissue. The change in FDG accumulation was compared with changes in serum prostate specific antigen (PSA) level and prostate size. FDG accumulation in the prostate decreased in all patients 1-5 months after the initiation of hormone therapy. The serum PSA level and prostate size measured on computerized tomography (CT) also decreased in these periods. A decrease in FDG accumulation was also demonstrated in metastatic sites. In this study, there appeared to be a decrease in FDG uptake in prostate cancer after endocrine therapy not only in primary prostate cancer lesions but also at metastatic sites, suggesting that the glucose utilization by tumours was suppressed by androgen ablation.

Estimation of coronary flow reserve with the use of dynamic planar and SPECT images of Tc-99m tetrofosmin

BACKGROUND

We developed a noninvasive method to examine coronary flow reserve with technetium 99m tetrofosmin based on the microsphere model. According to the microsphere model, myocardial blood flow (MBF) can be calculated by MBF = q / integral C(t)dt, where q is myocardial activity and C(t) is tracer concentration in blood. Because the ratio of integral C(t)dt at stress to rest is equal to the ratio of the first transit count in the pulmonary artery (PA) and attenuation factors were canceled out, we calculated the increase ratio of MBF (MBF(IR)).

METHODS AND RESULTS

After injection of dipyridamole, tetrofosmin was injected as a bolus and serial dynamic planar images were obtained to measure the first transit count in PA (PAC). Myocardial single photon emission computed tomography was performed to measure the regional myocardial count (RMC). MBF(IR) was calculated as [(RMCs x PACr)/(RMCr x PACs) - 1] x 100, where r and s denote resting and stress conditions, respectively. In contrast, the increase in the myocardial uptake ratio (MUR(IR)) was defined as (RMCs x SCr/RMCr x SCs - 1) x 100, where SC is syringe count of tracer. The results were as follows: (1) The mean MBF of healthy subjects was 46.9% +/- 22.8%. (2) MBF(IR) of the infarcted region and ischemic region was significantly decreased (8.3% +/- 12.2% and 11.2% +/- 11.9%, respectively; P <.001). (3) MUR(IR) was significantly lower than MBF(IR) (14.1% +/- 21.2%; P <.001). (4) MBF(IR) decreased according to the heart rate at rest (r = 0.47; P <.05).

CONCLUSIONS

MBF(IR) is a potential parameter with which to evaluate coronary flow reserve when the changes of arterial input function during stress are considered.

Functional mapping of human medial frontal motor areas. The combined use of functional magnetic resonance imaging and cortical stimulation

Two functional brain-mapping techniques, functional magnetic resonance imaging (fMRI) and cortical stimulation by chronically implanted subdural electrodes, were used in combination for presurgical evaluation of three patients with intractable, partial motor seizures. Brain mapping was focused on characterizing motor-related areas in the medial frontal cortex, where all patients had organic lesions. Behavioral tasks for fMRI involved simple finger and foot movements in all patients and mental calculations in one of them. These tasks allowed us to discriminate several medial frontal motor areas: the presupplementary motor areas (pre-SMA), the somatotopically organized SMA proper, and the foot representation of the primary motor cortex. All patients subsequently underwent cortical stimulation through subdural electrodes placed onto the medial hemispheric wall. In each patient, the cortical stimulation map was mostly consistent with that patient's brain map by fMRI. By integrating different lines of information, the combined fMRI and cortical stimulation map will contribute not only to safe and effective surgery but also to further understanding of human functional neuroanatomy.

Copper-62 ATSM as a hypoxic tissue tracer in myocardial ischemia

Copper-62 labeled diacetyl-bis(N4-methylthiosemicarbazone) (62Cu-ATSM) has been proposed as a generator produced positron-emitting tracer for hypoxic tissue imaging. To clarify the usefulness of 62Cu-ATSM for myocardial ischemia, 62Cu-ATSM PET was performed in 7 patients with coronary artery disease. Increased myocardial uptake of 62Cu-ATSM was observed (myocardium/blood ratio: 3.09) in one patient with unstable angina, who had increased 18F-fluorodeoxyglucose (18F-FDG) uptake under the fasting condition. The other 6 patients, who were clinically stable, did not have increased 62Cu-ATSM uptake, although abnormal 18F-FDG uptake was seen in 4 patients. This preliminary study suggests that 62Cu-ATSM is a promising PET tracer for hypoxic imaging in acute ischemia.

Clinical significance of reverse redistribution on resting thallium-201 imaging in patients with vasospastic angina

To evaluate the clinical significance of reverse redistribution (RR) of resting 201Tl single photon emission computed tomography (SPECT) in patients with vasospastic angina (VSA), we performed left ventriculography, coronary angiography and resting 201Tl-SPECT in 22 patients with VSA. Left ventriculography showed abnormal wall motion in 17 of 22 patients (77%) and 37 of 154 segments. Thirty-one of these 37 segments (84%) were within the area perfused by coronary arteries showing acetylcholine-induced vasospasm. On 201Tl images, abnormal findings were observed in 11 of 22 patients (50%), and among them, 7 patients (32%) had RR. Seven of 37 segments (19%) having abnormal regional wall motion had RR of 201TI, and in 6 of these 7 segments (86%), accumulation of 123I-BMIPP was found to be reduced. We conclude that repetitive brief myocardial ischemia may cause myocardial injuries in patients with VSA, and that the presence of RR of 201Tl indicates the presence of myocardial injury in these patients.

Abnormal magnetization transfer ratios in normal-appearing white matter on conventional MR images of patients with occlusive cerebrovascular disease

BACKGROUND AND PURPOSE

Chronic hypoperfusion may cause ischemic insult in the deep white matter. The magnetization transfer phenomenon is associated with the amount and constitution of myelin. The purpose of this study was to assess the usefulness of the magnetization transfer ratio (MTR) for detecting vasculometabolic abnormalities on positron emission tomography (PET) studies in patients with unilateral severe stenosis of the internal carotid artery (ICA).

METHODS

MTR maps and PET data-including regional cerebral blood flow (rCBF), regional cerebral metabolic rate of oxygen (rCMRO(2)), and regional oxygen extraction fraction (rOEF)-were investigated in 13 patients with unilateral severe stenosis of the ICA. The same regions of interest were selected in the white matter both on MTR maps and PET scans. The areas were classified into three groups based on MTR values (group 0, MTR >47.22%; group 1, MTR = 45.77% to 47.22%; group 2, MTR <45.77%), and the relationship between MTR and PET data was analyzed by means of both absolute values and asymmetric index (AI).

RESULTS

Abnormal values could not be detected in the areas classified as group 0. The areas classified as group 1 were characterized by absolutely normal values of rCMRO(2) and increased rOEF with AI, which was assessed as viable and reversible on the PET study. The areas classified as group 2 showed decreased rCMRO(2) with absolute values, which was considered irreversible in PET. A significant overall linear correlation was found between MTR and rCMRO(2) values.

CONCLUSION

Using the MTR technique to classify ischemic damage into three groups (normal, reversible, and irreversible), we found a significant correlation between the reduction of MTR and that of rCMRO(2) in white matter with ICA stenosis. We believe that the MTR technique may partly replace PET data in the assessment of ischemic injury.

An introduction to PET and SPECT neuroreceptor quantification models

PET and SPECT using appropriate radioligands allow imaging of certain critical components of neurotransmission such as presynaptic transporters and postsynaptic receptors in living human brains. PET and SPECT data are commonly analyzed by applying tracer kinetic models. These modeling approaches assume a compartmental system and derive the outcome measure called the binding potential, which reflects the densities of transporters or receptors in a brain region of interest. New models are often noninvasive in that they do not require arterial blood sampling. In this review, the concept and principles of tracer kinetic modeling are introduced and commonly used PET and SPECT neuroreceptor quantification models are discussed.

Brain perfusion SPECT study with 99mTc-bicisate: clinical pitfalls and improved diagnostic accuracy with a combination of linearization and scatter-attenuation correction

To evaluate the usefulness of a combination of linearization and scatter-attenuation correction on 99mTc-bicisate (ECD)-single photon emission tomographic (SPECT) images, both cerebral blood flow (CBF)-positron emission tomographic (PET) images and ECD-SPECT images from fifteen patients with chronic cerebral infarction were acquired. We measured radioactivity counts in regions of interest (ROIs) on all sets of both images and obtained a 2D scattered graph between ECD-SPECT and CBF-PET data. To evaluate diagnostic accuracy, the sensitivity, specificity and accuracy of ECD-SPECT images were calculated by means of discriminant analysis. The same analysis was also performed on the ECD-SPECT images corrected by a combination of linearization and scatter-attenuation correction. An overall nonlinear relationship was observed between ECD-SPECT and CBF-PET. The sensitivity, specificity, and accuracy of ECD-SPECT images were 69.6%, 91.4% and 73.0%, and those of ECD images corrected by the combination of linearization and scatter-attenuation correction were 79.5%, 95.7% and 82.0% respectively. The clinically diagnostic accuracy of ECD-SPECT images corrected by the combined method apparently increased. So that the linearization with the scatter-attenuation method is useful for improving the diagnostic accuracy of ECD-SPECT images.

Acute effects of stereotactic radiosurgery on the kinetics of glucose metabolism in metastatic brain tumors: FDG PET study

Hyperacute changes in the expression of glycolysis-associate gene products as well as FDG uptake in tumor cells after high-dose irradiation reflect response of the cells to noxious intervention and may be a potential indicator of the outcome of treatment. To understand acute effects on the kinetics of glucose metabolism of tumors in vivo after high-dose irradiation, we analyzed dynamic FDG PET data in patients with metastatic brain tumors receiving stereotactic radiosurgery.

MATERIALS AND METHODS

We studied 5 patients with metastatic brain tumors by means of dynamic FDG PET before and 4 hours after stereotactic radiosurgery. Rate constants of glucose metabolism (K1*- k3*) were determined in a total of 13 tumors by a non-linear least squares fitting method for dynamic PET and arterial blood sampling data. Rate constants after radiosurgery were compared with those before radiosurgery. Changes in the rate constants induced by the therapy were also correlated with changes in tumor size evaluated by CT and/or MRI 6 months later.

RESULTS

Four hours after radiosurgery, the phosphorylation rate indicated by k3* was significantly higher (0.080 +/- 0.058) than that before radiosurgery (0.049 +/- 0.023) (p < 0.05, paired t test), but there was no significant change in the membrane transport rates indicated by K1* and k2*. Although increases in the net influx rate constant K* (= K1*k3*/(k2* + k3*)) were correlated with increases in k3*, K* after radiosurgery (0.027 +/- 0.011) was not significantly different from that before the therapy (0.024 +/- 0.012). The reduction in the tumor size was correlated with k3* after radiosurgery.

CONCLUSION

Acceleration of the phosphorylation process was demonstrated in vivo in metastatic brain tumors as early as 4 hours after stereotactic radiosurgery, as shown experimentally in vitro in a previous report. The phenomenon may be a sensitive indicator of cell damage.

Dynamic changes in glucose metabolism accompanying the expression of the neural phenotype after differentiation in PC12 cells

To assess what properties of glucose metabolism are most closely related to expression of the neural phenotype, some parameters of glucose metabolism in PC12 cells before (tumor-type) and after differentiation (neuron-type) were investigated. Neuron-type cells exhibited a 2.7-fold higher level of [3H]DG retention than tumor-type cells, accompanied by a higher glucose transport rate and higher levels of hexokinase activity. [14C]CO2 production from [U-14C]glucose in neuron-type was also more than four-times greater than that in tumor-type cells. The levels of [14C]carbon in macromolecules from [14C]glucose in neuron-type cells were also much higher (10.6-fold) than those in tumor-type cells, and the levels of incorporation of [14C]carbon were almost as high as those of [14C]CO2. From the metabolite analysis, amino acids appeared to be the major compounds converted from glucose. On the other hand, the uptakes of [35S]methionine-[35S]cysteine and [3H]uridine in neuron-type cells were lower than those in tumor-type cells. Following depolarization with 50 mM potassium, [14C]CO2 production increased, but the retention of [14C]carbon was not changed in neuron-type cells. The largest change accompanied by acquisition of the neural phenotype was carbon incorporation into the macromolecules derived from glucose. This property may be important for the expression of the neural phenotype as well as the higher levels of both glucose uptake and oxygen consumption.

Ultrasound activates the auditory cortex of profoundly deaf subjects

Using three-dimensional PET, the cortical areas activated by bone-conducted ultrasound were measured from five profoundly deaf subjects and compared with the cortical areas of normal-hearing subjects activated by stimuli through bone-conducted ultrasonic, air-conducted, bone-conducted, and vibro-tactile hearing aids. All of the hearing aids, including the ultrasonic hearing aid, consistently activated the medial portion of the primary auditory cortex of the normal volunteers. The same cortical area was also significantly activated in the profoundly deaf subjects although the percentage increase in regional cerebral blood flow (rCBF) was smaller than in normal subjects. These results suggest that extra-cochlear routes convey information to the primary auditory cortex and can therefore produce detectable sound sensation even in the profoundly deaf subjects, who reported a sensation themselves.

Age-related changes in energy production in fresh senescence-accelerated mouse brain slices as revealed by positron autoradiography

To investigate age-related changes in cerebral energy production, we compared senescence-accelerated prone mice (SAMP8) as an animal model of accelerated aging and senescence-accelerated resistant mice (SAMR1) as a control. Considering that the cerebral glucose metabolic rate (CMRglc) at the time of O(2) deprivation and 2,4-dinitrophenol (DNP) loading would reflect anaerobic glycolytic capacity and mitochondrial function, respectively, we investigated dynamic changes in CMRglc before and after loading with these perturbations. Fresh brain slices were incubated with [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) in oxygenated Krebs-Ringer solution at 36 degrees C, and serial two-dimensional time-resolved images of [(18)F]FDG uptake in these slices were obtained on the imaging plates. The fractional rate constant (=k(3)*) of [(18)F]FDG proportional to the CMRglc was evaluated by applying the Gjedde-Patlak graphical method to the image data. The k(3)* value before the hypoxic perturbation in all of the brain sites analyzed was higher in SAMP8 than SAMR1 in both the 2- and 10-month-old groups. With O(2) deprivation, k(3)* values were higher without site specificity in the 2-month-old SAMP8 than in 2-month-old SAMR1, whereas in 10-month-old mice, there was no significant difference between the two groups. In contrast, with DNP loading, while no significant difference was noted between 2-month-old SAMP8 and 2-month-old SAMR1, in 10-month-old mice, the SAMP8 group showed lower values in certain regions than SAMR1 mice. These results suggest that in the brain tissue of SAMP8, a marked transient enhancement of anaerobic glycolytic capacity in the 2-month-olds and a decrease in mitochondrial function in the subsequent period occur, as a result of which glucose metabolism appears to be enhanced in both the 2- and 10-month-old groups compared to SAMR1 mice.

Corrosion behavior and surface structure of orthodontic Ni-Ti alloy wires

The corrosion behaviors of a commercial Ni-Ti alloy orthodontic wire and a polished plate with same composition in 0.9% NaCl and 1% lactic acid solutions were examined using an electrochemical technique, an analysis of released ions, and a surface analysis by X-ray photoelectron spectroscopy (XPS). The effect of polishing the wire on the corrosion was also examined. The XPS analysis demonstrated the presence of a thick oxide film mainly composed of TiO2 with trace amounts of Ni hydroxide, which had formed on the wire surface during the heat treatment and subsequent pickling processes. This oxide layer contributed to the higher resistance of the as-received wire to both general and localized corrosion in 0.9% NaCl solution, compared with that of the polished plate and the polished wire. The thick oxide layer, however, was not stable and did not protect the orthodontic wire from corrosion in 0.1% lactic acid solution.

An fMRI study of the functional neuroanatomy of picture encoding in younger and older adults

Age-related changes in the neural mechanisms of picture encoding were investigated using functional magnetic resonance imaging (fMRI). Seven younger and seven older adults were studied while they were encoding pairs of concrete-related, concrete-unrelated, and abstract pictures. Functional (T2*-weighted) and anatomical (T1-weighted) images of the brain were obtained using a 1.5 T MRI scanner. The results in the younger adults showed that the left dorsal prefrontal cortex (PFC) was activated during associative learning of the concrete-unrelated or abstract pictures. The results also suggest that both ventral and dorsal visual pathways are involved in the encoding of abstract pictures, and that the right superior parietal lobule likely mediates spatial information of the abstract pictures. The older adults showed significant activation in the left dorsal PFC under concrete-unrelated and abstract conditions. However, the older adults failed to activate either the left ventral and right dorsal PFC under the concrete-unrelated condition, or the parietal areas under abstract condition. A direct comparison between the two age groups demonstrates that the older adults had a reduced activation in the bilateral parieto-temporo-occipital areas under abstract condition, and in the right temporo-occipital area extending to the fusiform gyrus under the concrete-unrelated condition. Finally, age difference was found in correlation between memory performance and amplitude of signal change in the parahippocampal gyrus and fusiform gyrus under the concrete-unrelated and abstract conditions. These changes in neural response likely underlie the age-related memory decline in relation to pictorial information.

Characterization of acetate metabolism in tumor cells in relation to cell proliferation: acetate metabolism in tumor cells

To reveal the metabolic fate of acetate in neoplasms that may characterize the accumulation patterns of [1-(11)C]acetate in tumors depicted by positron emission tomography. Four tumor cell lines (LS174T, RPMI2650, A2780, and A375) and fibroblasts in growing and resting states were used. In uptake experiments, cells were incubated with[1-(14)C]acetate for 40 min. [(14)C]CO(2) was measured in the tight-air chamber, and the metabolites in cells were identified by thin layer chromatography and paper chromatography. The glucose metabolic rate of each cell line was measured with [2,6-(3)H]2-deoxy-glucose (DG), and the growth activity of each cell line was estimated by measuring the incorporation of [(3)H]methyl thymidine into DNA. Compared with resting fibroblasts, all four tumor cell lines showed higher accumulation of (14)C activity from [1-(14)C]acetate. These tumor-to-normal ratios of [1-(14)C]acetate were larger than those of DG. Tumor cells incorporated (14)C activity into the lipid-soluble fraction, mostly of phosphatidylcholine and neutral lipids, more prominently than did fibroblasts. The lipid-soluble fraction of (14)C accumulation in cells showed a positive correlation with growth activity, whereas the water-soluble and CO(2) fractions did not. These findings suggest that the high tumor-to-normal ratio of [1-(14)C]acetate is mainly due to the enhanced lipid synthesis, which reflects the high growth activity of neoplasms. This in vitro study suggests that [1-(11)C]acetate is appropriate for estimating the growth activity of tumor cells.

[A case of radiologically negative small-cell lung carcinoma successfully detected early by whole-body FDG-PET]

A 68-year-old man was referred to our hospital after being treated for early gastric cancer to investigate the causative malignancy, as his serum carcinoembryonic antigen (CEA) level was increased. Chest radiography showed no abnormal opacities. Subsequently, a whole-body FDG-PET was performed, which detected some tiny lesions in the mediastinum and the right lower lung field. A diagnosis of small-cell lung carcinoma was made after mediastinoscopic and bronchoscopic examinations. After chemoradiotherapy, the previously abnormal uptake of FDG was attenuated and the bronchoscopic appearance was improved, while the serum CEA and NSE levels returned to normal. Our findings demonstrated that whole-body scanning by FDG-PET could be useful for early detection of lung cancer, especially in cases of small-cell lung cancer.

Naming of animals and tools: a functional magnetic resonance imaging study of categorical differences in the human brain areas commonly used for naming visually presented objects

To investigate the neural substrates for naming objects and their category-dependency, we performed functional magnetic resonance imaging (fMRI) with naming of animals and tools. Naming objects, irrespective of their category, activated left frontal to bilateral parietal regions and occipital to posterior temporal regions. Within these areas, naming animals caused more activation of the primary visual cortex bilaterally and the ventral occipital cortex to the inferior temporal area on the right side. Naming tools caused more activation of the posterior part of the left middle temporal area, the rostral part of the left inferior parietal lobule, and the left inferior frontal cortex. These findings suggest that the neural network for naming objects has discrete category-dependent nodes through which pertinent conceptual knowledge may be mediated.

A new method to estimate rCBF using IMP and SPECT without any blood sampling

We developed and evaluated a method to measure rCBF without any blood sampling by using iodine- 123 IMP and SPECT. An integral of arterial input function, the integral taken from the value 0 to T of the variable Ca(t)dt, can be expressed as TC(T)/CO, where TC(T) is radioactivity delivered to the body in T minutes and CO is cardiac output. If T is acceptably small, rCBF can be determined by means of a microsphere model analysis with IMP as Cb(T)/(TC(T)/CO), where Cb(T) is cerebral radioactivity at T minutes. We derived TC(T) and CO from a chest dynamic scan. The method was applied to 45 patients who underwent rCBF studies (58 studies) with arterial blood sampling (ABS). Data from the chest scan were analyzed in comparison with ABS data in the first 28 studies, and equations for correction yielding an accurate TC(T)/CO were derived. The validity of the proposed method was evaluated in the subsequent 30 studies. The method yielded rCBF (rCBF-test) which agreed well with rCBF obtained by a two-compartment model analysis of dynamic SPECT and ABS data (rCBF-ref) with the mean and SD of differences between rCBF-test and rCBF-ref being 1.0 and 2.7 ml/100 g/min, respectively. In eleven subjects who underwent more than two studies, a percentage change in rCBF-test between the studies also closely approximated that of rCBF-ref (y = 1.11 x + 2.63, r = 0.92). The method can be used with acceptable reliability to measure rCBF without any blood sampling.

Noninvasive estimation of FDG input function for quantification of cerebral metabolic rate of glucose: optimization and multicenter evaluation

The aims of this study were to determine whether body weight or body surface area (BSA) should be used for noninvasive measurement of the cerebral metabolic rate of glucose (CMRGlc) by FDG PET with a standardized input function (SIF) and an autoradiographic method and to validate the procedure in a large population from different PET centers.

METHODS

Plasma input functions measured by intermittent arterial blood sampling after intravenous injection of FDG, in 101 patients from 1 institution who were fasting for at least 4 h, were used to generate the SIF. The SIF was generated by averaging over 101 patients the input function normalized with the net injected dose and initial distribution volume (DV) of FDG estimated by the formula c x Ha x Wb, where H is body height and W is body weight. To evaluate the estimation of DV by BSA or body weight, the coefficient of variation (CV) of the ratio of Ha x Wb to the measured DV was calculated by changing a and b independently. Estimation of the CMRGlc with SIF based on the formula for DV was validated with an additional 192 subjects from 3 institutions who underwent FDG PET while fasting. The result of simulation was compared with the results of 4 previously published formulas for BSA and body weight.

RESULTS

The optimal set of parameters, in which a was 0.80 and b was 0.35, minimized the CV. The averaged percentage error of the CMRGlc based on the optimal set of parameters for DV estimation and SIF was 8.9% for gray matter and 10.6% for white matter. Four BSA formulas brought about a similar error, which was significantly smaller than that based on body weight (P < 0.001, ANOVA).

CONCLUSION

Noninvasive estimation of CMRGlc is made possible by careful measurement of the net injected dose and BSA.

Evaluation of 62Cu labeled diacetyl-bis(N4-methylthiosemicarbazone) as a hypoxic tissue tracer in patients with lung cancer

62Cu labeled diacetyl-bis(N4-methylthiosemicarbazone) (62Cu-ATSM) has been proposed as a generator-produced, positron-emitting tracer for hypoxic tissue imaging. From basic studies, the retention mechanism of 62Cu-ATSM is considered to be closely related to cytosolic/microsomal bioreduction, a possible system for hypoxic bioreductive drug activation. In order to evaluate the characteristics of 62Cu-ATSM, PET studies were performed in 4 normal subjects and 6 patients with lung cancer. 62Cu-ATSM cleared rapidly from the blood with little lung uptake (0.43+/-0.09, uptake ratio; divided by the arterial input function) in normal subjects. Intense tumor uptake of 62Cu-ATSM was observed in all patients with lung cancer (3.00+/-1.50). A negative correlation was observed between blood flow and flow-normalized 62Cu-ATSM uptake in three of four patients. In contrast, 62Cu-ATSM uptake was not related to that of 18F-fluorodeoxyglucose. The negative correlation between blood flow and flow normalized 62Cu-ATSM uptake suggests an enhancement of retention of 62Cu-ATSM by low flow. 62Cu-ATSM is a promising PET tracer for tumor imaging, which might bring new information for chemotherapeutic treatment as well as radiotherapy of hypoxic tumors.

[Evaluation of fluorine-18-fluorodeoxyglucose whole body positron emission tomography imaging in the clinical diagnosis of lung cancer]

In recent years the use of positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) has become a valuable tool in the detection of a variety of tumors including lung cancer. To determine its role in the diagnosis of patients with suspected lung cancer, we compared the results of FDG-PET with those of the other scintigraphic imaging techniques (67Ga-planar image, 201Tl-SPECT and 99mTc-bone scintigraphy) used worldwide in patients with lung cancer. The analysis group consists of 178 patients, 159 malignant pulmonary diseases and 19 benign pulmonary diseases. FDG-PET was performed in 65 patients (51 malignant pulmonary diseases, 14 benign pulmonary diseases). FDG-PET had a sensitivity, specificity and accuracy of 98.0%, 78.6% and 93.8%, respectively, in detecting malignant pulmonary nodules. In N staging, sensitivity, specificity and accuracy were 66.7%, 81.3% and 76.0%, respectively. In M staging, the accuracy was 100%. Thus, FDG-PET imaging was more accurate than the other types of scintigraphic imaging. In our observations, whole-body 18FDG-PET images improved diagnostic accuracy in the evaluation of lung lesions and the staging of lung cancer.

Difference in the metabolic response to photic stimulation of the lateral geniculate nucleus and the primary visual cortex of infants: a fMRI study

The metabolic change that occurs during early development of the human brain was studied with functional magnetic resonance imaging (fMRI), in which the signal change reflects the balance between the supply and the demand of oxygen during stimulus-related neuronal activation. The subjects were 16 infants, aged < 1 year. They were sedated with pentobarbital, and 8-Hz flickering light was intermittently projected onto their eyelids. Two age groups were analyzed: infants < 60 days old and > 60 days old (corrected for gestational age at birth). The stimulus-related signal change was positive in the lateral geniculate nucleus regardless of the infants' age, but in the primary visual cortex reversed from positive in the younger group to negative in the older group. It is known that synaptogenesis in the lateral geniculate nucleus peaks before birth, and in the primary visual cortex accelerates in the second month after birth. Hence, the inversion of the stimulus-related signal change in the primary visual cortex may be due to an increased demand for oxygen owing to rapid synaptogenesis.