355-nm direct-detection Doppler wind lidar for vertical atmospheric motion measurement.

A compact and simple 355-nm direct-detection Doppler wind lidar (DDDWL) was developed to measure the line-of-sight (LOS) wind speed of the background atmosphere from atmospheric molecule return signals with and without aerosols and clouds. A receiver design with a Fabry-Perot etalon interferometer (FPEI) without an inside deposited step coating or fiber coupling is considered for the DDDWL using the double-edge technique. The receiver with the double-edge technique uses a FPEI and wedge prism to form a double-edge filter. The development of the double-edge filter in this combination is, to the best of our knowledge, an improvement at 355-nm wavelength. Considerations for the DDDWL receiver with a FPEI revealed that a full-angle light beam divergence into the FPEI and a working FPEI aperture are significant factors for the receiver design. Preliminary experimental evaluation demonstrated that the DDDWL had the potential of LOS wind speed measurements with a random error of less than 1 m/s when the signal-to-noise ratio was approximately 300. The DDDWL-measured vertical LOS wind speed profile was consistent with that of a 2-µm coherent Doppler wind lidar within the measurement error range. The preliminary experimental LOS wind measurement results demonstrated the capability of the DDDWL to measure low LOS wind speeds.

[Development of Body Phantom for Evaluation of Appropriate Administered Radioactivities and Image Quality on 99mTc-DMSA Scintigraphy in Pediatric Nuclear Medicine].

PURPOSE: We conducted a field survey about pediatric nuclear medicine. As a result, it was suggested that 99mTc-DMSA scintigraphy was performed at many institutions, whereas various examinations such as image acquisition and processing are not carried out using the renal phantom. Therefore, we developed the body phantom for the evaluation of appropriate administered radioactivities and image quality with renal scintigraphy in pediatric nuclear medicine. METHODS: We created three differently sized body phantoms (1-, 5-, and 20-year-old models). These pediatric body phantoms were filled with a 99mTc solution based on the consensus guideline of pediatric radiopharmaceutical administered radioactivity in Japan. The planar image was evaluated using acquisition count, uniformity and defect contrast. SPECT images were evaluated with a recovery coefficient (RC). RESULTS: The acquisition counts for pediatric body phantoms were relatively corresponded to the clinical study. The appropriate acquisition counts and the pixel size for the planar image were approximately 140 counts per pixel and 1.23-1.35 mm at 5 min acquisition times in 1- and 5-year-old pediatric body phantom studies, respectively. Although the uniformity and the cold contrast did not depend on pixel size and body size, the cold contrast was affected by body size. The RC for SPECT images depended on the performance of SPECT systems, the resolution recovery algorithm and body phantom size. CONCLUSION: The developed pediatric body phantom could allow us to establish optimal image acquisition and more evidence on renal scintigraphy in pediatric nuclear medicine.

Precise measurement of laser power using an optomechanical system.

This paper shows a novel method to precisely measure the laser power using an optomechanical system. By measuring a mirror displacement caused by the reflection of an amplitude modulated laser beam, the number of photons in the incident continuous-wave laser can be precisely measured. We have demonstrated this principle by means of a prototype experiment uses a suspended 25 mg mirror as an mechanical oscillator coupled with the radiation pressure and a Michelson interferometer as the displacement sensor. A measurement of the laser power with an uncertainty of less than one percent (1σ) is achievable.

Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector.

The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17 and 18 K. The detector sensitivity, which was limited by the mirror's thermal fluctuation at room temperature, was improved in the frequency range of 90 to 240 Hz by cooling the mirrors. The improved sensitivity reached a maximum of 2.2×10(-19) m/√Hz at 165 Hz.

Direct measurement of thermal fluctuation of high-Q pendulum.

We have achieved a direct measurement of the thermal fluctuation of a pendulum in an off-resonant and wide frequency region using a laser interferometric gravitational-wave detector. These measurements have been well identified for over one decade by an agreement with a theoretical prediction, which is derived by a fluctuation-dissipation theorem. Thermal fluctuation was dominated by the contribution of resistances in coil-magnet actuator circuits. When we tuned these resistances, the noise spectrum also changed according to a theoretical prediction. The measured thermal noise level corresponds to a high quality factor on the order of 10(5) of the pendulum.

Development of a displacement- and frequency-noise-free interferometer in a 3D configuration for gravitational wave detection.

The displacement- and frequency-noise-free interferometer (DFI) is a multiple laser interferometer array for gravitational-wave detection free from both the displacement noise of optics and laser frequency noise. So far, partial experimental demonstrations of the DFI have been done in 2D table top experiments. In this Letter, we report the complete demonstration of a 3D DFI. The DFI consists of four Mach-Zehnder interferometers with four mirrors and two beam splitters The attained maximum suppression of the displacement noise of both mirrors and beam splitters was 40 dB at about 50 MHz. The nonvanishing DFI response to a gravitational wave was successfully confirmed using multiple electro-optic modulators and computing methods.

Search for a stochastic background of 100-MHz gravitational waves with laser interferometers.

This Letter reports the results of a search for a stochastic background of gravitational waves (GW) at 100 MHz by laser interferometry. We have developed a GW detector, which is a pair of 75-cm baseline synchronous recycling (resonant recycling) interferometers. Each interferometer has a strain sensitivity of approximately 10;{-16} Hz;{-1/2} at 100 MHz. By cross-correlating the outputs of the two interferometers within 1000 seconds, we found h{100};{2}Omega_{gw}<6 x 10;{25} to be an upper limit on the energy density spectrum of the GW background in a 2-kHz bandwidth around 100 MHz, where a flat spectrum is assumed.

Resonant speed meter for gravitational-wave detection.

Gravitational-wave detectors have been well developed and operated with a high sensitivity. However, they still suffer from mirror displacement noise. In this Letter, we propose a resonant speed meter as a displacement noise-canceled configuration based on a ring-shaped synchronous recycling interferometer. The remarkable feature of this interferometer is that, at certain frequencies, gravitational-wave signals are amplified, while displacement noises are not.

Improved breast cancer detection of prone breast fluorodeoxyglucose-PET in 118 patients.

OBJECTIVE: To prospectively evaluate the breast cancer detection of prone breast positron emission tomography (PET) images in comparison with supine whole-body PET images. MATERIAL AND METHODS: One hundred and eighteen female patients (age range 28-91 years) with 122 lesions suspected of having breast cancer underwent fluorine-18 fluorodeoxyglucose PET for preoperative staging. After the whole-body image was acquired, prone breast PET imaging was performed. The findings from both images were compared with the histopathologic results. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy were used to compare the diagnostic accuracy of prone breast PET images with that of whole-body PET images. RESULTS: Sensitivity, specificity, positive predictive value, NPV, and accuracy of whole-body PET images were 83, 50, 97, 17, and 80%, and of prone breast PET images they were 95, 50, 96, 43, and 93%. Ten of 114 breast cancerous lesions (8.8%) were detected on prone breast PET images alone. Statistical difference was found between the sensitivity, accuracy, and NPV of prone breast PET images and those of whole-body PET images (P<0.0001 for sensitivity and accuracy and P<0.0009 for NPV). CONCLUSION: Our data about the 122 lesions, suspected of breast cancer, with regard to the usefulness of prone breast PET imaging indicate that prone breast PET images are effective in detecting breast cancer.

Demonstration of displacement- and frequency-noise-free laser interferometry using bidirectional Mach-Zehnder interferometers.

We have demonstrated displacement- and frequency-noise-free laser interferometry (DFI) by partially implementing a recently proposed optical configuration using bidirectional Mach-Zehnder interferometers (MZIs). This partial implementation, the minimum necessary to be called DFI, has confirmed the essential feature of DFI: the combination of two MZI signals can be carried out in a way that cancels displacement noise of the mirrors while maintaining gravitational-wave signals. The attained maximum displacement-noise suppression was 45 dB.

[Development of automatic analysis for dynamic renal function study using computed tomographic (CT) images].

Determination of the region of interest (ROI) for dynamic renal function has been highly discordant among operators because of the dependence on factors such as the rate of injection of radioactive medicines, constitution, and renal function. To simplify this problem, we developed a computer algorithm that provides automatic analysis for both localization of the kidney and automatic determination of ROIs using computed tomographic (CT) images. The bilateral kidneys were extracted from enhanced CT images, and the CT pixel size was adjusted to dynamic renal function images. The template-matching technique was used for these images, and the kidney renal location was analyzed on additional functional images constructed by dynamic renal function images. As a result, we were able to obtain time-activity curves of both renal function and quantified glomerular filtration rate (GFR). In conclusion, the computer algorithm we developed was considered to provide reliable results, apart from the variability among operators, because of its good reproducibility.

[Development of automatic analyses for star-shot images using computed radiography (CR)].

Recent progress in radiation therapy has been greatly enhanced in many facilities by the development of new machines for treatment, improved computer technology for radiotherapy treatment planning systems (RTPs), increased accuracy of radiation therapy such as stereotactic irradiation, and intensity-modulated radiation therapy (IMRT). Quality control (QC) of the isocenter, which has consisted of gantry rotation and limiting the radiation field, is important for greater accuracy of these radiation therapy technologies. Star-shot analyses using computed radiography (CR) for evaluation of the isocenter were employed in this study. Devices to support CR were created, and a method of automatically analyzing images obtained by the star-shot technique, which calculated the error (distance) from the isocenter and the incident beam angle, were developed. In terms of the accuracy of our method, the average maximum error was 0.33 mm (less than 2 pixels: 0.35 mm), the average absolute error and incident beam angle errors were 0.3 mm and 0.4 degrees at maximum and at one standard deviation (SD), respectively. In this study, the processing times were 16 sec at minimum, 152 sec at maximum, 18 sec at most frequencies, and 23.6 sec on average. In conclusion, it was considered that our newly developed method for analyzing star-shot images using CR enabled immediate, quantitative evaluation of the isocenter.

Interferometers for displacement-noise-free gravitational-wave detection.

We propose a class of displacement- and laser-noise-free gravitational-wave-interferometer configurations, which does not sense nongeodesic mirror motion and laser noise, but provides a nonvanishing gravitational-wave signal. Our interferometers consist of four mirrors and two beam splitters, which form four Mach-Zehnder interferometers. By contrast to previous works, no composite mirrors with multiple reflective surfaces are required. Each mirror in our configuration is sensed redundantly, by at least two pairs of incident and reflected beams. Displacement- and laser-noise-free detection is achieved when output signals from these four interferometers are combined appropriately. Our 3-dimensional interferometer configuration has a low-frequency response proportional to f2, which is better than the f3 achievable by previous 2-dimensional configurations.

Displacement- and timing-noise-free gravitational-wave detection.

Motivated by a recently invented scheme of displacement-noise-free gravitational-wave detection, we demonstrate the existence of gravitational-wave detection schemes insusceptible to both displacement and timing (laser) noises and are thus realizable by shot-noise-limited laser interferometry. This is possible due to two reasons: first, gravitational waves and displacement disturbances contribute to light propagation times in different manners; second, for an N-detector system, the number of signal channels is of the order Omicron(N(2)), while the total number of timing- and displacement-noise channels is of the order Omicron(N).

[Research on time-course differential imaging by bone scintigraphy].

The temporal image subtraction technique was applied to bone scintigraphy, using Photoshop (commercially available image processing software) and Morpher (public domain warping software). For the temporal subtraction images, 81 subtraction images (19 cases) were prepared by a method used to subtract the previous images from the current ones. Registration of the current and previous images was performed by manual operation using Photoshop, and warping was done using the warping function of Morpher. In addition, difference images prepared after correcting the distributions of radioactive isotopes of the current and previous images using the count of the pelvic region were also examined. Compared with manual operation, alignment of images by warping improved registration and reduced the generation of pseudo-images of subtraction images. The rate of identification of abnormal accumulation-enhanced regions and subjective evaluation by doctors was improved for warping more than for manual operation. Furthermore, abnormal hot regions, which are difficult to find in film images, could be found in three subtraction images. In addition, it was confirmed that abnormal hot regions become more visible in many cases by preparing subtraction images after correcting the count between images using the count of the pelvic region. Thus, it is suggested that the temporal image subtraction technique in bone scintigraphy enables more accurate observation of enhancement of or changes in abnormal hot regions, which will support diagnostic reading. It is considered that enhancement of or changes in abnormal hot regions will be more accurately understood through further detailed discussion in the future.

Power-recycled resonant sideband extraction interferometer with polarization detection.

Second-generation interferometric gravitational-wave detectors will use a technique called resonant sideband extraction (RSE) to improve the sensitivity in a narrow, tunable, frequency band. We present a configuration in which we use polarization detection to allow a continuously tunable power-recycled RSE interferometer for a control scheme similar to those of the first-generation detectors. A mathematical model describing this configuration and the results from a tabletop prototype are presented that demonstrate this configuration.

Development of a frequency-detuned interferometer as a prototype experiment for next-generation gravitational-wave detectors.

We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors.

No regional differences of cytochrome P450 expression in the liver of Cynomolgus monkeys (Macaca fascicularis).

Non-human primates are frequently used in toxicological studies the result of which are extrapolated to humans, but background data on drug metabolism ability among monkeys derived from different countries has not been published, especially on the key enzyme, cytochrome P450 (CYP450). We assessed the amounts of hepatic CYP450 obtained from cynomolgus monkeys of different ages and from different countries in this study. There were no regional differences of total P450 content, as well as major CYP450 isozymes (CYP 1A, 2A, 2B, 2C, 2D, 2E1 and 3A4) in cynomolgus monkeys by westernblot analysis. Similarly, there were no significant differences with hybrid cynomolgus monkeys, but variations in individual values were large. As for aging, total P450 contents declined in old cynomolgus monkeys (12-32 years of age). These results indicate the usefulness of basic data of hepatic CYP450 obtained from cynomolgus monkeys of different ages and from different countries.