|Akihiko Takahashi||Last modified date：2021.05.18|
Associate Professor / Fundamental Radiological Sciences / Department of Health Sciences / Faculty of Medical Sciences
|1.||Monte Carlo study on possibility of Ra-223 SPECT imaging.|
|2.||Yuya Sekikawa, Keita Funada, Kazuhiko Himuro, Akihiko Takahashi, Shingo Baba, Masayuki Sasaki, Molecular imaging of 177Lu for hepatic tumor using Monte Carlo simulation and investigation of acquisition condition, SNMMI 2019 annual meeting, 2019.06, 【Background】
177Lu is used for therapy PRRT of neuroendocrine tumors. Although 177Lu formulation is not approved domestically. There is a possibility of being used clinically in the future, and it is necessary to establish imaging method and treatment effect prediction method before clinical use.
This study aimed to generate 177Lu SPECT images using a homemade Monte Carlo simulation code and examine the influence of images due to changes in acquisition time.
This study is used result of a previous study have shown the time-activity curve for a 177Lu dose of 7.4GBq and an average weight of 77 kg. The simulation is an in-house code called HEXAGON NAI based on Monte Calro simulation of electron and photon (MCEP). The phantom is modeled on NEMA IEC BODY phantom and code in the simulation. The collimator type is middle energy general purpose (MEGP) and code in simulation. The background was assumed to be liver, the spherical insert was assumed to be a tumor. The radioactivity concentration of the background and the spherical insert were 155 kBq/ml and 2.12 MBq/ml at 24 hours after administration. Similarly, the radioactivity concentrations calculated for 6 hours and 72 hours later using time activity curve and 177Lu SPECT images were generated for each time. Also, images when the acquisition time was changed to 12, 6, 3, 2, 1.5 and 1.2 minutes was generated and contrast recovery coefficient (CRC) and contrast noise ratio (CNR) were calculated for each images.
In 6 hours later images, CRC maximum value is 75.2%, CNR maximum value is 71.2. In 24 hours later images, CRC maximum value is 113.2%, CNR maximum value is 102.6. In 72 hours later images, CRC maximum value is 72.9%, CNR maximum value is 116.3. In the case that sphere size is 13 mmΦ, time is 6 hours later and acquisition time is 1.5 minutes, CNR is 4.8 and it was invisible. In the case that sphere size is 10 mmΦ, time is 6 hours later and acquisition time is all condition, it was invisible. In the case that sphere size is 10 mmΦ, time is 24 hours later and acquisition time is 3.0 minutes, CNR is 3.6 and it was invisible. In the case that sphere size is 10 mmΦ, time is 72 hours later and acquisition time is 2.0 minutes, CNR is 2.3 and it was invisible. Namely, in the case that sphere size is 17~37mmΦ and acquisition time is all condition, it was visible. Also, in the case that sphere size is 13mmΦ, time is 6 hours later, it is necessary to spend more than 1.5 minutes. In the case that sphere size is 10mmΦ, time is 6 hours later, it was invisible. In the case that sphere size is 10mmΦ and time is 24 hours later, it was necessary to spend more than 3 minutes. In the case that sphere size is 10mmΦ and time is 24 hours later, it was necessary to spend more than 2 minutes.
177Lu SPECT images were able to generate for each time using Monte Calro simulation. Also, acquisition time to generate 177Lu SPECT images was able to be shorted..
|3.||Monte Carlo Simulation of Ra-223 SPECT Images Using Digital Phantom.|
|4.||Impact of difference in activity concentration and size of lesion on the detectability with Channelized Hotelling Observer.|
|5.||Impact of positron range on PET images: A simulation study.|
|6.||Keita Funada, Akihiko Takahashi, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki, Investigation of Collimator Broad Correction for Dopamine Transporter SPECT Imaging using Monte Carlo Simulation, SNMMI 2018 Annual Meeting, 2018.06, 【Purpose】Dopamine transporter (DaT) single-photon emission computed tomography (SPECT) is used in the diagnosis of Parkinson’s syndrome and dementia with Lewy bodies. The accumulation of 123I-ioflupane in a striatum decreases in these diseases. The collimator removes scattered rays and improves image quality in SPECT. However, the spatial resolution of images is decreased by the collimator septa. The striatum is a small tissue and deeply located; hence, it can be easily affected by spatial resolution deterioration in the SPECT device. Thus, correcting the spatial resolution in imaging the accumulation of 123I-ioflupane is essential. The widely used spatial resolution correction methods are collimator broad correction (CBC) and three-dimensional frequency distance relationship (3D-FDR). CBC is used for the ordered subset expectation maximization (OSEM) method, and 3D-FDR is used for the filtered back projection (FBP) method. The purpose of this study is to quantitatively assess the influence of spatial resolution correction on DaT SPECT images using Monte Carlo simulation.
【Method】The simulation is an in-house code called Monte Carlo simulation of electron and phantom (MCEP). The CT image of the striatum phantom data was installed in the simulation code as a voxel data. The number of voxels was 512 × 512 × 76, and the dimension of voxel was 0.6 × 0.6 × 1 mm . The radioactivity concentration of the background is 5.56 kBq/mL or 7.44 kBq/mL. The ratio of the activity concentrations in the striata to that in the background was (right striatum, left striatum) = (6.03, 3.01) and (8.04, 4.03). The collimator of the gamma camera was an LEHR collimator. The image reconstruction software used was the Prominence ProcessorTM (version 3.1). The Butterworth filter (cutoff frequencies: 0.5 cycles/cm, order: 8) was applied to the projection data. Image reconstruction was carried out using the OSEM (iteration = 6, subset = 10) with or without the CBC and the FBP with or without the 3D-FDR. The projection images were reconstructed with attenuation correction (Chang method) and scatter correction of a triple energy window. The reconstructed images were evaluated using contrast recovery coefficient (CRC). The CRC value was calculated using the region-of-interest of the right and left striata and the background.
【Result】The CRC value of the images reconstructed using FBP with 3D-FDR was 73.3%, and the CRC of the images without 3D-FDR was 62.4 %. On the contrary, the CRC of the images constructed using OSEM was 73.3%, and the CRC of the images without the CBC was 63.7%.
【Conclusion】The CRC values were improved more than 10% using the spatial resolution correction. There was little difference between the OSEM and the FBP method.
|7.||Assessment of Ra-223 gamma-ray imaging using Channelized Hoteling Observer.|
|8.||Assessment of optimal collimator in Ra-223 SPECT imaging: A Monte Carlo study.|
|9.||舟田 圭汰、高橋 昭彦 、氷室 和彦、馬場 眞吾、佐々木 雅之, モンテカルロシミュレーションによるドパミントランスポータSPECT画像におけるコリメータ開口補正の影響の検討, 第74回日本放射線技術学会総会学術大会, 2018.04, 【目的】ドパミントランスポータ(DAT)イメージング剤のSPECT画像のモンテカルロシミュレーション(MCS)を行い、コリメータ開口補正がDAT画像の画質や定量評価へ与える影響を調査した。【方法】MCSコードはガンマカメラコードHEXAGON/NAIをSPECT用に改造したものである。線条体ファントムを512×512×76(縦・横・奥行)、ボクセルサイズ0.6mm×0.6mm×1mmのボクセルデータとしてコードに組み込んだ。I-123濃度はバックグラウンド(BG)である大脳皮質部分で5.56kBq/mLと7.44kBq/mLとし線条体とBGの比はそれぞれ(右,左)=(8.04,4.03),(6.03,3.01)とした。核医学用画像処理ソフトProminence Processor(PP)を用いて線条体ファントムを画像化した。再構成法はOSEM、再構成条件はIteration=6, Subset=10とし、吸収補正はChang法、散乱補正はTEW法とした。右線条体、左線条体、BGに関心領域をそれぞれ設定して、線条体平均放射能濃度の回収率を算出した。３種類のコリメータについて点線源拡がりの距離依存性をMCSで求めPPの開口補正係数として設定して、開口補正再構成画像を作成した。【結果】低エネルギー汎用（LEGP）コリメータに対する回収率は(補正なし,開口補正あり) =(47.7%,57.4%)、低エネルギー高分解能（LEHR）コリメータに対する回収率は(補正なし,開口補正あり) =(53.1%,63.5%)、高エネルギー汎用（HEGP）コリメータに対する回収率は(補正なし,開口補正あり) =(41.6%,52.8%)となった。【結論】コリメータ開口補正によって、回収率が10％程度向上することがわかった。.|
|10.||Investigation of lesion detectability in 223Ra images using Channelized Hotelling Obserber method.|
|11.||Monte Carlo simulation of Ra-223 SPECT imaging.|
|12.||Simulation of PET/SPECT imaging using MCEP code -for radionuclide therapy-.|
|13.||Ryota Ohima, Akihiko Takahashi, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki, Impact of Collimator on 223Ra Imaging: a Monte-Carlo Study, The SNMMI(Sosiaty of Nuclear Medicine and Molecular Imaging)2017 Annual Meeting , 2017.06, Purpose: Radium-223 (223Ra) is an alpha-emitting radionuclide used in unsealed radionuclide therapy for bone-metastatic prostate cancer. Alpha rays have a short range and high energy. Thus, it is important to comprehend their movement in a patient’s body. In this study, we investigated the impact of collimator on 223Ra abdominal imaging using Monte Carlo simulation.
Methods: The Monte Carlo codes are HEXAGON and NAI; these were developed by Tanaka and Uehara. The HEXAGON code simulates the behavior of the photon and electron in the phantom and collimator, and then, the NAI code simulates their behavior in the gamma camera, including the optical components and scintillator, producing projection images. We installed a numeric phantom that was created using computed tomography (CT) images of an abdominal phantom. 223Ra was distributed in the third lumbar vertebral region, and 22 X-rays and gamma rays were installed. The width of the energy window was determined to be 20% of 84 keV-photopeak (76–92 keV), in accordance with previous studies. We examined two low-energy, general-purpose (LEGP) collimators (Collimators I and II) and two medium-energy, general-purpose (MEGP) collimators (Collimators III and IV). The collimator dimensions, i.e., septal thickness and hole diameter, were 0.017 cm and 0.178 cm for Collimator I, 0.025 cm and 0.190 cm for Collimator II, 0.084 cm and 0.26 cm for Collimator III, and 0.11 cm and 0.337 cm for Collimator IV, respectively. The collimator height was 4.0 cm. The event number of decay was 108.
Results: As the septal thickness increased, the simulated projection images seemed clearer. Detection sensitivity (cps/MBq) is an important factor in imaging. We simulated energy spectra for each image from which sensitivities were derived. The total sensitivities of the gamma camera were 131 cps/MBq for Collimator I, 80.1 cps/MBq for Collimator II, 41.9 cps/MBq for Collimator III, and 69.5 cps/MBq for Collimator IV. The fractions of sensitivity due to unscattered photons, indicating the image quality, were 6.35 (I), 11.0 (II), 27.4 (III), and 29.4 % (IV). The sensitivities for LEGP were much larger than those for MEGP; however, the fractions of unscattered photons for MEGP were larger than those for LEGP. This is because thick septa effectively removed scattered photons and lead fluorescence.
Conclusions: In this investigation, the most favorable collimator for superior image quality was the Collimator IV, which had the thickest septum and the largest hole diameter. However, an excessively large hole diameter increases photon scatter and degrades spatial resolution. Therefore, other collimators need to be investigated for various 223Ra distributions.
|14.||Monte Carlo Simulation on Collimator Dependencies at 223Ra Imaging for Alpha Ray Radionuclide Therapy.|
|15.||Investigation of Optimum Collimator Conditions for Dopamine Transporter SPECT Imaging using Monte-Carlo Simulation.|
|16.||Akihiko Takahashi, Kazuhiko Himuro, Shingo Baba, Masayuki Sasaki, A Monte Carlo simulation of 223Ra imaging for unsealed radionuclide therapy, 22th International Conference on Medical Physics (ICMP2016), 2016.12, Purpose: Radium-223(Ra-223), an alpha-emitting radionuclide, is used in unsealed radionuclide therapy for metastatic bone tumors. Our purpose is to investigate the feasibility and utility of Ra-223 imaging using an in-house Monte Carlo simulation code.
Methods: A three-dimensional numeric phantom was installed in the simulation code. Ra-223 accumulated in a part of the spine, and 22 gamma rays between 80 and 450 keV were selected as the emitted photons. We also simulated technetium-99m(Tc-99m) imaging under the same conditions and compared the results.
Results: The sensitivities of the three photopeaks were 147 counts per unit of source activity (cps/MBq; photopeak: 84 keV, full width of energy window: 20%), 166 cps/MBq (154 keV, 15%), and 158 cps/MBq (270 keV, 10%) for a low-energy general-purpose (LEGP) collimator, and those for the medium-energy general-purpose (MEGP) collimator were 33 cps/MBq, 13 cps/MBq, and 8.0 cps/MBq, respectively. In the case of Tc-99m, the sensitivity was 55 cps/MBq (141 keV, 20%) for LEGP and 52 cps/MBq for MEGP. The fractions of unscattered photons of the total photons reflecting the image quality were 0.09 (84 keV), 0.03 (154 keV), and 0.02 (270 keV) for the LEGP collimator and 0.41, 0.25, and 0.50 for the MEGP collimator, respectively.
Conclusions: Our simulation study revealed that the most promising scheme for Ra-223 imaging is an 84-keV window using an MEGP collimator. The sensitivity of the photopeaks above 100 keV is too low for Ra-223 imaging..
|17.||高橋 昭彦, 三輪 建太, 佐々木 雅之, 馬場 眞吾, Monte Carlo Simulation of 223Ra imaging for unsealed radionuclide therapy, 第72回日本放射線技術学会総会学術大会, 2016.04.|
|18.||Reiho Amano, Atsushi Sasanuma, Thanh-Hung Dinh, Goki Arai, Yusuke Fujii, AkihikoTakahashi, Daisuke Nakamura, Tatsuo Okada, Tetsuya Makimura, Taisuke Miura, Akira Endo, Tomas Mocek, Padraig Dunne, Gerry O’Sullivan, Takeshi Higashiguchi, Development of a 10-Hz short pulse CO2 laser for short wavelength light sources, SPIE/OSJ Biophotonics Japan 2015, 2015.10.|
|19.||Monte Carlo Simulation of DAT-SPECT Imaging
|20.||R. Amano, T. H. Dinh, A. Sasanuma, G. Arai, Y. Fujii, K. Nanto, A.Takahashi, D. Nakamura, T. Okada, T. Makimura, T. Miura, A. Endo, T. Mocek, P. Dunne, G. O’Sullivan, T. Higashiguchi, Development of short pulse CO2 laser for efficient rare earth plasma extreme ultraviolet sources, 2015 IEEE Photonics Conference, 28th Annual Conference of The IEEE Photonics Society, 2015.10.|
|21.||T. H. Dinh, R. Amano, A. Sasanuma, G. Arai, Y. Fujii, A.Takahashi, D. Nakamura, T. Okada, T. Makimura, T. Miura, A. Endo, T. Mocek, P. Dunne, G. O’Sullivan, T. Higashiguchi, An efficient 6.x nm extreme ultraviolet source produced by a short pulse CO2 laser, The 7th Asian Workshop on Generation and Application of Coherent XUV and X-ray Radiation (7th AWCXR), 2015.08.|
|22.||Akihiro Shiba, Akihiko Takahashi, Kazuhiko Himuro, Yasuo Yamashita, Singo Baba, Masayuki Sasaki, Comparison images between PET and SPECT of 90Y: A Monte-Carlo simulation study, The 2015 Society of Nuclear Medicine and Molecular Imaging （SNMMI） Annual Meeting, 2015.06, [URL].|
|23.||Masato Kawasaki, Atsushi Sasanuma, Goki Arai, Hiroyuki Hara, Yusuke Fujii, Kenichiro Nanto, Akihiko Takahashi, Daisuke Nakamura, Tatsuo Okada, Tetsuya Makimura, Taisuke Miura, Akira Endo, Bowen Li, Padraig Dunne, Gerry O’Sulliban, Efficient extreme ultraviolet emission in highly ionized high-Z laser-produced plasmas, The 4th Advanced Lasers and Photon Sources (ALPS’15), 2015.04.|
|24.||芝 弘晃, 高橋 昭彦, 佐々木 雅之, モンテカルロシミュレーションによる90Y-PET/SPECTの検知限界に関する研究, 第71回日本放射線技術学会総会学術大会, 2015.04, 【Purpose】The SPECT image for the bremsstrahlung emitted from Yttrium-90 used in targeted radionuclide therapy for malignant lymphoma and the PET image for the internal pair production were generated using our own custom Monte-Carlo simulation codes to examine the detection limit. 【Method】 We used an NEMA IEC Body Phantom containing six hot spheres. Each sphere included the activity concentrations of 1–6 MBq/mL of Yttrium-90 and the background concentration included 1/10–1/40 for the hot spheres. Acquisition time was set to 30 min. In the case of SPECT, the number of the projections was set to 120°/360°. We used the “Prominence Processor®” software to reconstruct the SPECT projection images and to evaluate some reconstructed images. In the case of PET, we used our own custom software to reconstruct the PET images. 【Result】 The contrast recovery coefficient (CRC) and the contrast noise ratio (CNR) for hot spheres decreased with decreasing diameter of the hot sphere and with the decreasing hot sphere-background concentration ratio. In the case of 1–6 MBq/mL concentration in the hot spheres, the CNR for a 10-mm hot sphere was lower than 5.0 in all conditions for SPECT. Therefore, a 10 mm hot sphere could not be identified by SPECT. The CNR for a 13 mm or larger hot sphere was higher than 5.0 only for the case of the hot sphere-background ratio of 1/40. In PET, when the hot sphere-background ratio was as high as 1/20.|
|25.||Investigation on detection llimits of 90Y-PET and SPECT- part I.|
|26.||Investigation on detection llimits of 90Y-PET and SPECT- part I.|
|27.||Monte Carlo Simulation of PET and SPECT of 90Y.|
|28.||Application to nuclear medicine of the Monte Carlo simulation.|
|29.||Monte Carlo simulation of 131I-SPECT.|
|30.||Development of the Monte Carlo simulation cord of 90Y-SPECT.|
|31.||Investigation on the Time-of-Flight effect of the PET image using the Monte Carlo simulation.|
|32.||Monte Carlo simulation of 90Y -PET measurement using internal pair production.|
|33.||Nobuhiko Siguura, Shuichi Torii, Tetsuya Makimura, Yoshiyuki Ichinosawa, Kota Okaaki, Daisuke Nakamura, Akihiko Takahashi, Tatsuo Okada, Hiroyuki Niiro, Kouichi Murakami, Micromachining of PMMA using Laser Plasma Soft X-Rays for Fabrication of 3D Molds in a Micrometer Scale, The 14th International Symposium on Laser Precision Microfabrication , 2013.07.|
|34.||Nbuhiro Sugiura, Shuichi Torii, Tetsuya Makimura, Kota Okazaki, Daisuke Nakamura, Akihiko Takahashi, Tatsuo Okada, Hiroyuki Niiro, Kouichi Murakami, Ablation Process of PMMA Induced by Irradiation with Laser Plasma EUV light, The 10th Conference on Laser and Electro-Optics Pacific Rim, 2013.07.|
|35.||Shintaro Fukami, Shuichi Torii, Tetsuya Makimura, Kota Okazaki, Daisuke Nakamura, Akihiko Takahashi, Tatsuo Okada, Hiroyuki Niiro, Kouichi Murakami, Micromachining of Polydimethylsiloxane usining Laser Plasma Soft X-rays, The 14th International Symposium on Laser Precision Microfabrication, 2013.07.|
|36.||Tetsuya Makimura, Shuichi Torii, Daisuke Nakamura, Akihiko Takahashi, Tatsuo Okada, Hiroyuki Niiro, Kouichi Murakami, Responses of organic and inorganic materials to intense EUV radiation from laser-produced plasmas, SPIE Optics + Optelectronics 2013, 2013.04.|
|37.||Micromachining of PMMA using Laser Plasma Soft-X rays for Fabrication of 3D Molds in a Micrometer Scale.|
|38.||Development of the Monte-Carlo simulation cord of PET scanner.|
|39.||Monte-Carlo simulation of the 90Y-PET imaging.|
|40.||Micromachining using EUV radiation from laser produced plasma.|
|41.||Micromachining of Poly(methyl methacrylate) Using Laser Plasma Soft X-Rays.|
|42.||Monte Carlo Simulation of Retinal Vessel Image.|
|43.||Characteristics of micromachining of Silicon Rubber Using Laser Plasma Soft X-rays.|
|44.||Testuya Makimura, Shuichi Torii, Kota Okazaki, Daisuke Nakamura, Akihiko Takahashi, Hiroyuki Niiro, Tatsuo Okada, Kouichi Murakami, Responce of polymers to laser plasma EUV light beyond ablation threshold and micromachining , SPIE Optics + Optelectronics 2011, 2011.04.|
|45.||Influence of Light Scattering on Retinal Vessel Oxymetry.|
|46.||Monte Carlo Simulation of Retinal Vessel Oxymetry.|
|47.||Micromachining of transparent materials using laser plasma x-rays.|
|48.||Micromachining of Silicon Rubber Using Laser Plasma Soft X-rays.|
|49.||Micromachining of transparent materials using Fresnel diffraction of infrared radiation.|
|50.||Micromachining of SiO2 by TEA CO2 laser Fresnel diffraction light through the metal mask.|
|51.||Micromachining of SiO2 by near-field ablation using 10.6μm TEA CO2 laser..|
|52.||Micromachining of SiO2 by Fresnel diffraction of TEA CO2 laser light with the metal mas.|
|53.||Micromachining of SiO2 by TEA CO2 laser near-field light.|
|54.||Direct micromachining of transparent materials using EUV radiation from laser produced plasma.|
|55.||Development of Laser-Produced Plasma Extreme Ultraviolet Light Source for Micromachining of Transparent Materials.|
|56.||Study on Micromachining of Transparent Materials Using Laser Plasma Soft X-rays.|
|57.||Micromachining of transparent materials using EUV radiation from CO2 laser produced plasma.|
|58.||Micromachining of transparent materials using EUV radiation from CO2 laser produced plasma.|
|59.||Development of Extra-ultraviolet Lithography Light Source.|
|60.||Comparative study on emission characteristics of debris from CO2 and Nd: YAG laser-produced plasmas.|
|61.||CO2 laser-produced Sn plasma for optical lithography.|
|62.||The Triggering Effect on Discharge of Laser-Produced Plasma with Tin Target.|
|63.||Measurement of ion energy generated in laser-produced plasma.|
|64.||Visualization of Particle Behavior from Laser-Produced Plasma.|
|65.||Development of visualization system of nuetral deblis emitted from Sn-LPP for EUV light source.|
|66.||Development of Extreme Ultraviolet Light Source in Kyushu University.|
|67.||Development of EUV Light Source for Optical Lithography by CO2 Laser-Produced Plasmas.|
|68.||Visualization of Deblis Behavior from CO2 Laser-Produced Plasma for EUV Light Source.|
|69.||Visualization of nuetral Xe in CO2 laser-produced plasma.|
|70.||Emission Characteristics of EUV ligth source from CO2 laser produced plasma.|
|71.||Characteristics of EUV emission from CO2 laser produced plasma using Xe target
Hiroki Tanaka, Kouji Akinaga, Akihiko Takahashi, Tatsuo Okada.
|72.||Development of a broad-band light source using fiber Raman laser
Mitsuhiro Higashihata, Tadashi Nakamura, Yoshiki Nakata, Tatsuo Okada, Akihiko Takahashi, N. Vasa.
|73.||Development of a target for laser-produced plasma EUV light source using Sn nano-particle
Hiroki Tanaka, Kouji Akinaga, Akihiko Takahashi, Tatsuo Okada
7th International Coference on Laser Abration.
|74.||Characteristic of EUV emission from CO2 laser produced plasma
Hiroki Tanaka, Kouji Akinaga, Akihiko Takahashi, Kiichiro Uchino, Tatsuo Okada
The 64th Autumn Meeting,2003,The Japan Society of Applied Physics.
|75.||Extreme ultra-violet generation pumped by CO2 laser produced-plasma
Akihiko Takahashi, Hiroki Tanaka, Kiichiro Uchino, Tatsuo.Okada
2nd International Extreme UltraVioket Symposium.
|76.||Developement of a target for laser-produced plasma EUV light source using Sn nano-particle
Hiroki Tanaka, Akihiko Takahashi, Tatsuo Okada
The 50th Spring Meeting,2003, The Japan Society of Applied Physics and Related Societies.
|77.||Spectral dynamics of narrow-band F2 laser for optical lithography
Hiroki Tanaka, Akihiko Takahashi, Tatsuo Okada, T.Ariga, Ryoichi Nohdomi, Kazuaki Hotta, Hakaru Mizoguchi
The Third Asian Pacific Laser Symposium.
|78.||Numerical simulation of spectral dynamics of narrow-band F2 laser for optical lithography
Hiroki Tanaka, Akihiko Takahashi, Tatsuo Okada, Ryoichi Nohdomi, Kazuaki Hotta, Hakaru Mizoguchi
The 49th Spring Meeting,2002, The Japan Society of Applied Physics and Related Societies.
|79.||Ar2 excimer emission from laser-heated plasma
Hiroki Tanaka, Akihiko Takahashi, Tatsuo Okada, Mitsuo Maeda, Kiichiro Uchino
10th International Symposium on Laser-aided Plasma Diagnostics.
|80.||Ar2 excimer emission from laser-heated plasma
Akihiko Takahashi, Tatuo Okada, Mitsuo Maeda, Kiichiro Uchino
The 4th Pacific Rim Conference on Lasers and Electro-Optics.
|81.||Numerical simulation of spectral dynamics of narrow-band F2 lasers I
Akihiko Takahashi, Tatsuo Okada, Ryoichi Nohdomi, Kazuaki Hotta, Hakaru Mizoguchi
The 48th Spring Meeting,2001, The Japan Society of Applied Physics and Related Societies.
|82.||Ar2 excimer emission spectra in laser-heated plasma
Akihiko Takahashi, Tatsuo Okada, Takashi Hiyama, Mitsuo Maeda, Kiichiro Uchino, Toshihiro Nisisaka, Akira Sumitani, Hakaru Mizoguchi
The 48th Spring Meeting,2001, The Japan Society of Applied Physics and Related Societies.
|83.||Ar2 excimer generation pumped by laser-heated plasma
Takashi Hiyama, Akihiko Takahashi, Tatsuo Okada, Mitsuo Maeda, Kiichiro Uchino ,Katsunori Muraoka, Tatsuo Enami, Hakaru Mizoguchi
The 47th Spring Meeting,2000, The Japan Society of Applied Physics and Related Societies.
|84.||Improvement of output energy of a discharge-pumped ArF excimer laser by Xe gas addition
Naoki Kataoka, Motoya Itagaki, Kiichro Uchino, Katsunori Muraoka, Akihiko Takahashi, et.al
20th Annual Meeting of The Laser Society of Japan.
|85.||Ar2 dimer production by laser-heated plasma pumping.|
|86.||Vacuum ultraviolet emission from laser-heated plasma in high-pressure Ar gas
Akihiko Takahashi, Tatsuo Okada, Mitsuo Maeda, Kiichiro Uchino, Katsunori Muraoka
9th International Symposium on Laser-aided Plasma Diagnostics.
|87.||Theoretical analysis of re-ser-pumped Ar2* excimer laser
AkihikoTakahashi, Tatsuo Okada
The 45th Spring Meeting,1998, The Japan Society of Applied Physics and Related Societies.
|88.||Vacuum ultraviolet emission from laser-heated high-pressure Ar plasma
Akihiko Takahashi, Tatsuo Okada, Kiichiro Uchino, Mitsuo Maeda, Katsunori Muraoka, Hakaru Mizoguchi, Tatsuo Enami
The 46th Spring Meeting,1999, The Japan Society of Applied Physics and Related Societies.