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As a result of applying super-resolution near-field structure to a magneto-optical disk with a non-magnetic mask layer such as a silver oxide light scattering center type mask layer, we could retrieve the signals of below 200-nm mark length. With the improved antimony transparent aperture type mask layer, in this work, we could get the polarized magneto-optical signals as well that we had not been able to obtain by using the previous antimony mask layer. This was well agreed with computer simulation result. Another optimization, such as magnetic layer thickness, dielectric materials and so on, was also investigated for a better magneto-optical disk of super-resolution near-field structure with a silver oxide light scattering center type mask layer.

The current study focused on the tea plant (Camellia sinensis) as a target for artificial cultivation because of the variation in its components in response to light conditions. We analyzed its sensory quality by multi-marker profiling using multicomponent data based on metabolomics to optimize the conditions of light and the environment during cultivation. From the analysis of high-quality tea samples ranked in a tea contest, the ranking predictive model was created by the partial least squares (PLS) regression analysis to examine the correlation between the amino-acid content (X variables) and the ranking in the tea contest (Y variables). The predictive model revealed that glutamine, arginine, and theanine were the predominant amino acids present in high-ranking teas. Based on this result, we established a cover-culture condition (i.e., a low-light intensity condition) during the later stage of the culture process and obtained artificially cultured tea samples, which were predicted to be high-quality teas. The aim of the current study was to optimize the light conditions for the cultivation of tea plants by performing data analysis of their sensory qualities through multi-marker profiling in order to facilitate the development of high-quality teas by plant factories.

A technique for reducing cross-recording on data storage media with high track density is described. In order to detect cross-recording sensitively, an inverted mark pattern was first recorded on adjacent tracks and then synchronized with a normal recorded mark pattern on the central track. These patterns were repeatedly recorded as the recording power was increased. Readout signals of the recorded mark pattern were evaluated on the central track in each condition, and an optimum recording power was precisely determined from the maximum amplitude of the signals. When this new technique was applied to a magneto-optical disk, the bit error rate was reduced to less than 10/sup -4/. This is the first technique to reduce cross-recording by laser power only.

Acoustic emission (AE) signals induced from an alternating current (ac) NbTi superconducting coil were studied to observe the relationship between AE signals and the superconducting states of the winding of the ac coil, around the time of quenching initiation during operation at a commercial frequency of 50 Hz. The envelopes of the AE signals induced at quenching initiation were analyzed using information from operating currents and voltages in the coil. The AE signals rose and increased in accordance with the appearance and enhancement of the normal components for most cases in a series of quenching tests, where the quenching was initiated at the coil ends. In the case that the quenching was initiated by a different cause, the AE waveform had a different pattern, in which the AE signals started like a impulsive signal having slow decay, and normal zone propagation was not initiated at the moment when the AE signal started. Those differences are compared and discussed.

For practical applications of high-temperature superconductor tape, the high production rate of tapes is needed to reduce its cost. Recently, the long-length coated conductor with high performance has been fabricated by an ion beam assisted deposition/pulsed laser deposition (IBAD/PLD) method in Fujikura. In IBAD process, we adopted IBAD–Gd2Zr2O7 (GZO) film. The process speed of IBAD–GZO film was increased up to 5 m/h using a polished metal substrate tape. To fabricate biaxially-textured buffer layers at a higher rate, we have started to develop another structures such as (a) IBAD–GZO/IBAD–MgO (3-fold symmetry) and (b) IBAD–MgO (4-fold symmetry). In the case (a), we fabricated GdBCO/CeO2/IBAD–GZO/IBAD–MgO tape and the critical current was Ic = 550 A/cm (2.46 MA/cm2) and throughput of IBAD processes were 20 m/h. In the case (b), IBAD–MgO short samples with ΔΦ of 9°–11° were obtained at 500 m/h. The 500 m/h (10 mm width) is extremely high rate in IBAD process in the world. As long-length IBAD layer 10 m, 50 m and 100 m IBAD–MgO films were fabricated at the speed of 100 m/h. After CeO2 deposition, in-plane textures of these samples were ΔΦ of 3.7°–3.7°, 4.1°–4.9° and 4.2°–4.8°. Using some of these buffer layers, we have obtained GdBCO film with Ic = 400 A/cm (2 MA/cm2, 10 m) and Ic = 550 A/cm (2.7 MA/cm2, short sample).

Electrotransfection is an effective method for transfecting lymphoid cells. However, the transfection efficiency of certain lymphoid cells is low. L1210 subclones and NFS-70 pro-B cells, which are highly refractory to various transfection methods, were used to identify the limiting factors. Cells were electrotransfected with plasmids coding for green fluorescence protein or luciferase. The luciferase expression of L1210 subclone 3-3 was found to increase 6-12 h after electroporation, but decreased significantly from 12 to 48 h. The lower level of luciferase activity at later time periods correlated with decreases in cell viability, which was shown to be due to apoptosis, as determined by propidium iodide/acrindine orange staining, DNA laddering, and prevention of cell death by addition of caspase inhibitors. Similar results were observed with NFS-70 pro-B cells and select L1210 subclones. In contrast, L1210 parental and L1210 subclone 7-15.6 cells undergo only low levels of apoptosis (< or = 5%). Apoptosis occurred only when DNA (plasmids or salmon sperm DNA) was present during electroporation, but was not dependent on the conformation of the DNA used or the expression of transgenes. Cells pulsed in the presence of dextran sulfate (MW 500,000) did not apoptose. Similar results were observed when L1210 subclone 3-3 was transfected using the cationic lipid 1, 2-dioleoyl-3-trimethylammonium propane, although the transfection efficiency and corresponding rate of apoptosis were significantly lower. Applying the caspase inhibitor fluoromethyl ketone (Boc-ASP-FMK) dramatically improved cell viability and transgene expression of select L1210 subclones and NFS-70 pro-B cells.

In order to develop AC superconducting apparatus for power use, 10 kA/sub r.m.s./-class AC superconducting coils should be developed. From such a viewpoint, the authors have been investigating AC superconducting coils having a large AC transport current capacity. In this paper, the specification and experimental results of an 1 T/sub r.m.s.//1 kA/sub r.m.s./-class AC superconducting coil are shown. Two experimental AC coils using the sub-cable and single strand of this AC superconducting coil are also fabricated and tested to investigate the stability of AC coils. The quench current of each AC coil is measured and is compared to the DC critical current characteristics of the strand. From the result of the comparison, it is confirmed that the AC quench current of each superconducting coil is close to the DC quench current, and is close to the current which is determined by the critical current characteristics defined by 0.1 /spl mu/V/cm criterion. It is also confirmed that the quench point of the developed AC coil reaches to 1.396 T/sub peak//1288 A/sub peak/.

Acoustic emission (AE) induced from an alternating current (ac) superconducting coil was studied during operation in liquid helium. The operating current of the coil was increased from zero with a constant ramp rate at a commercial frequency of 50 Hz until quenching in the coil. The AE signals induced from the coil around the time of the quenching initiation were compared with the operating current, the coil voltage, and the phase difference between the current and the voltage in order to estimate the changes in those signals which resulted from the quenching process. The AE signals continued almost at very low levels before the quenching, At the moment of the quenching initiation, the AE signals clearly and drastically rose approximately 10-15 ms earlier than the decrease in the operating current or the phase difference. The AE signals induced by the wire motion during 50-Hz ac operation were also compared with the operating current.

Although tumor clearance is a common criterion in assessing the impact of radiotherapy (RT), it is not always reliable. Patterns of tumor clearance were determined using 91 metastatic lymph nodes (LNs) from 51 patients with head and neck tumors treated by definitive RT (61-80 Gy) or preoperative RT (43-65 Gy). Clearance rate (CR) was estimated as a daily volume decrement expressed as a ratio to the pre-RT LN volume. CR was greater for the so-called radioresponsive nasopharyngeal subgroups and more poorly differentiated than those of oral cavity and well-differentiated, respectively. Histologically, LNs that were removed following RT consisted mainly of fibrous tissues, necrotic tissues, and few cancer cells. There was no difference in CR between the cancer-cell-positive group (n = 21) and the cancer-cell-negative group (n = 31). Although the CR may reflect inherent radiosensitivity of tumor cells, tumor persistence predicts the amount of oncologically inactive materials rather than that of remaining cancer cells.

Long-length and low-cost coated conductors are necessary for practical use such as motor, generator, transformer, fault current limiter, SMES and so on. For fabricating low-cost coated conductors, production speeds at each process should be faster. The structure of coated conductor we adopted, is GdBa2Cu3Oy(GdBCO)/CeO2/Gd2Zr2O7 (GZO)/metal. To make processes faster without changing such beneficial structures, we adopted another buffer layer under GZO film. At the IBAD (ion-beam-assisted deposition) process, MgO is known as one of the suitable materials to achieve high alignment with thin film thickness. We fabricated IBAD-MgO film with changing deposition rates and ion-current densities, and got two types of IBAD-MgO film. One is the film with its crystal orientation aligned to the MgO(1 1 1) parallel to the tape surface, and the other is with MgO(1 0 0). And each film has in-plane texture such that 3-fold symmetry, and 4-fold symmetry respectively in the pole figure of MgO . We performed IBAD-GZO on the 3-fold IBAD-MgO film, and got 4-fold IBAD-GZO film. In-plane textures of GZO were not so different from the ordinary IBAD-GZO film, but the thickness of the films became from 1.2 μm to 0.3 μm (1/4). And a critical current of the GdBCO film on the buffer layer was over 210 A/cm (Jc > 1.5 MA/cm2) at 77 K.

We have obtained the good superconducting performance in Y-123 tapes made by Ion-Beam-Assisted Deposition (IBAD) and Pulsed Laser Deposition (PLD) method. In this paper, we describe recent progresses of long Y-123 conductor by IBAD/PLD process using reel to reel systems. Ic of 88 A was obtained in end to end of a 217 m long one. Furthermore, we developed the conduction cooled HTS test solenoid coil using 100 m-Y123 conductors. The results of coil operating tests are described.

Patterns of radiologic response of 10 thymomas treated by preoperative radiotherapy (RT) (18-20 Gy/2 weeks) were determined in conjunction with histologic response. Changes in tumor volume were evaluated with CT scans obtained 5 to 36 days before and 14 to 24 days after the initiation of RT and before surgery. The extent of tumor volume reduction (TR) varied widely (40-78%), while the mean daily volume decrement expressed as a percentage of the pre-RT tumor volume correlated significantly with the pre-RT tumor volume. Histologically, the tumors, all of which were resected 17 to 33 days after RT initiation, generally consisted of predominant fibrous tissues, rare necrotic foci, and few epithelial cells. The TR did not correlate with pre-RT tumor volume, observation period, histologic subtype, or quantity of remaining epithelial cells. The TR of thymomas does not predict RT impact on tumor cells but does reflect the quantity of inherent tumor stroma.

Conductor configuration and characteristics of superconducting cable for 50 Hz AC use are reported. We developed AC conductors aiming low loss kA class current capacity. In consideration of reducing the current degradation by cabling, structures suitable for AC conductor are designed. In these conductors, low loss AC superconducting wires with very fine NbTi filaments are stranded around central cable of Cu-Ni or stainless steel wires for equal cooling condition, equal current distribution and mechanical reinforcing. Characteristics of small coils with these conductor at 50 Hz AC load are tested and reported.

In an effort to develop optimal conditions for analysis of tumor specific T lymphocyte responses, we have studied the effect of changes in the concentration of oligonucleotide primers on the synthesis of TCR cDNAs in one step PCR procedure using Vbeta10 gene subfamily as a model. It was found that synthesis of the TCR cDNAs increases in a roughly linear fashion at primer concentrations between 0.005-0.05 muM. Evaluation of the use of low concentration (0.005 muM) of primers showed these conditions to be adequate for the analysis of TCR Vbeta subfamilies in the spleen of BALB/c mice, but not in the peritoneal exudate cells (PECs), the latter requiring ten-fold higher concentrations of the variable region primers to compensate for the overall low frequency of T lymphocytes in the PECs in comparison to the spleen. Use of these optimal conditions to detect L1210 tumor specific T lymphocyte responses showed that, in the immunized mice, L1210 specific T lymphocyte responses are detectable in the PECs, but not in the spleen cells from these mice. Thus, upon i.p. immunization of DBA/2 mice with irradiated L1210 lymphoma cells, followed by analysis of the PECs by RT/PCR, three TCR Vbeta subfamilies, including Vbeta8.2, Vbeta15 and Vbeta16 were found to contain specific major TCR cDNA bands. The approach described here is very efficient, as it uses a small amount of the 32P isotope (0.5 muCi) followed by direct analysis of the PCR products on a denaturing acrylamide/urea gel. Furthermore, data is also presented that shows that quantitative differences in the levels of individual TCR cDNAs in a particular Vbeta subfamily are preserved during PCR amplification.

Purpose : To determine the capacity of biological clearance in tumor regression following radiotherapy by using metastatic brain tumors as a clinical model in which mechanical clearance is negligible. Methods and Materials : Thirty-eight tumors (19 nonsmall cell lung cancer, 11 small cell lung cancer, and 8 nonlung cancer) in 23 patients were followed with computed tomography (CT) scans over 3 months or more following initiation of radiotherapy, with doses ranging between 34 and 66 Gy. The tumor regression rate (RR ; mm 3 /day), which represented the capacity of biological clearance, was calculated for each CT observation period. The complete response (CR) rate was calculated. The relationship between RR and tumor diameter was determined with regression analysis in conjunction with the pattern of contrast enhancement and the type of primary disease. The change of the RR also was examined. Results : The CR rate was 60.5% for the total group ; it was lower for ring-enhanced tumors (41.7%) than diffusely enhanced tumors (69.2%), which included mostly small cell lung cancer metastases. The RR correlated significantly with the tumor diameter (D), with a regression curve of exponential function (RR = 0.035 *D 2.5 ). The RR varied widely and was rather large until 40 days following initiation of radiotherapy, especially for the subgroups of diffusely enhanced tumors and the small cell lung cancer tumors, and became rather constant thereafter. Conclusion : A tumor diameter exponent in the regression curve of smaller than 3.0 indicates that the larger the tumor volume is, the smaller the capacity of biological clearance. The capacity of biological clearance also is dependent on vascularity and cellularity of the tumor components expressed by the pattern of contrast enhancement.

Chronic necrotizing pulmonary aspergillosis (CNPA), also called semi-invasive pulmonary aspergillosis, was first described in the early 1980s as a distinct type of pulmonary aspergillosis. CNPA was an indolent, cavitary, infectious process of the lung parenchyma secondary to local invasion by Aspergillus species. Diagnosis is confirmed by pathological evidence of lung tissue invasion by the fungus. Clinical diagnosis by combined clinical, radiological and laboratory findings is needed because histopathological confirmation cannot always be obtained in the clinical setting. CNPA is recognized as a clinical syndrome in Japan, and has been poorly defined histologically. We report three autopsy cases of CNPA evaluated histopathologically. Subjects were middle-aged to older men with a medical history of pulmonary mycobacterial infection who presented with pulmonary or systemic symptoms. Radiologically, progressive upper lobe cavitary infiltrates were seen with mycetomas and infiltration in lower lung fields. Clinically, CNPA was diagnosed based on 2007 Japanese guidelines for the diagnosis and treatment of deep fungal infection. Subjects died of respiratory failure within one month to three years of diagnosis despite antifungal therapy including micafungin, voriconazole, or itraconazole combined with broad spectrum antibiotics. Autopsy findings showed cavities containing the fungus but no fungal invasion of viable lung tissue. The area of progressive infiltration revealed bacterial pneumonia, organizing pneumonia or organizing diffuse alveolar damage without Aspergillus. In conclusion, CNPA is a chronic progressive clinical form of pulmonary aspergillosis with significant morbidity and mortality.

The authors have developed the disc format for land/groove recording on a magneto-optical disc in which only a single side of the groove is wobbled. The format is suited for a rewritable digital video disc system. >

Bit-by-bit detection at a recording density of 0.11 µm pits is achieved on a super-resolution near-field structure (super-RENS) disk with a platinum oxide layer. Pits and spaces are arranged as a recording pattern for pit position recording. The pattern is recorded on the disk with using a 635-nm-wavelength laser and an objective lens with a 0.6 numerical aperture. After recording using laser pulses with pre- and post-heating, the pattern is correctly reproduced despite a size that is smaller than the resolution limit. Furthermore, the readout durability is more improved than that of the previous silver oxide disk. The pattern is clearly digitized by a read channel circuit for bit-by-bit detection.

We explored the general feasibility of proton beam therapy for chordoma and chondrosarcoma of the skull base. Clinical records and treatment-planning data of patients with the pathological diagnosis of chordoma or chondrosarcoma were examined. Proton beam therapy was administered for gross tumor mass as well as microscopic residual disease after surgery. The prescribed dose was determined to maximize the coverage of the target and to not exceed predefined constraints for the organs at risk. Eight cases of chordoma and eight cases of chondrosarcoma were enrolled. The median tumor volume was 40 cm(3) (range, 7 to 546 cm(3)). The prescribed dose ranged from 50 to 70 Gy (relative biological effectiveness [RBE]), with a median of 63 Gy RBE. The median follow-up duration was 42 months (range 9 to 80 months). The overall survival rate was 100%, and the local control rate at 3 years of chordoma and chondrosarcoma were 100% and 86%. None of the patients developed radiation-induced optic neuropathy, brain stem injury, or other severe toxicity. Proton beam therapy is generally feasible for both chordoma and chondrosarcoma of the skull base, with excellent local control and survival rates.

Analysis of structural diversity at the 5' end of H-2 class I mRNAs showed that a small fraction of Kd mRNA from L1210 lymphoma (approximately 10%) or from various normal tissue (2-3%) of DBA/2 mice carries a precise deletion of the sequences encoding the second extracellular domain. Nucleotide sequence of the coding region of the second domain-lacking Kd mRNA was found to be identical to the known sequence of the Kd gene from DBA/2 liver with the exception of the above deletion and a single nucleotide silent substitution at position 150, suggesting that the novel Kd RNA is a product of the functional Kd gene. In addition, various normal tissues that are known to express varying levels of Kd antigen did not show changes in the expression levels of the second domain-lacking Kd mRNA thus ruling out the possibility that synthesis of this RNA is coupled to control the expression levels of the canonical Kd mRNA, hence the Kd antigen. Analysis by polymerase chain reaction showed that all normal tissues including the testis and sperm express this RNA. Preliminary analysis of the Kb mRNA from the spleen and thymus of C57BL/6 mouse also showed the presence of second domain-lacking Kb mRNA in these mice. Furthermore, preliminary structural analysis of the Dd and Ld mRNAs has revealed additional polymorphic extracellular domain-lacking mRNA species including a first domain-lacking Dd mRNA and two Ld mRNAs that lack sequences encoding either the first extracellular domain or the second extracellular domain respectively. These results together show that H-2 mRNAs lacking sequences that specify individual extracellular polymorphic domains are a frequent feature of the structural diversity at the 5' ends of these mRNAs. Potential significance of these domain-lacking H-2 mRNAs is discussed, particularly with regard to the function of the putative encoded peptides as targets of natural killer cells.

Intensity-modulated proton therapy (IMPT) is expected to improve treatment results with fewer side effects than other proton therapies. The purpose of this study was to evaluate the tumor sites for which IMPT was effective under the same beam calculation conditions by planning IMPT for typical cases treated with passive scattering proton therapy (PSPT). We selected 16 cases of nasal cavity, lung, liver or prostate cancers as typical tumor sites receiving PSPT. The dose distributions and dose volume histograms optimized by the IMPT were compared with those optimized by the PSPT. We took particular note of the doses to the skin and organs at risk (OAR) when PSPT was replaced by IMPT. Furthermore, an improvement of the beam angles was also performed to obtain better dose distributions in the IMPT. The IMPT with the same beam angles resulted in near-maximum doses to the skin of average 78%, 64%, 84% and 99% of the PSPT doses for nasal cavity, lung, liver, and prostate cancers, respectively. However, it was difficult to improve the dose homogeneity of the target volume. The change of the IMPT beam angles could reduce the doses to OARs and skin in the case of the nasal cavity, while it had limited effect in the other cases. We concluded that IMPT was effective for reducing the doses to some OARs when treating nasal cavity, lung, liver and prostate cancers. The selection of beam angles was important in the IMPT optimization, especially for nasal cavity cancers.

We present results of reactively sputtered silver oxide thin films as a substrate material for surface-enhanced Raman spectroscopy (SERS). Herein, we show that deposited layers develop an increasingly strong SERS activity upon photoactivation at 488 nm. A benzoic acid/2-propanol solution was used to demonstrate that the bonding of molecules to SERS active sites at the surface can be followed by investigating temporal changes of the corresponding Raman intensities. Furthermore, the laser-induced structural changes in the silver oxide layers lead to a fluctuating SERS activity at high laser intensities which also affects the spectral features of amorphous carbon impurities.

A proposal for a photonic transistor is made and some basic proving experiments are described. These experiments show that by focusing two laser beams (405 and 635 nm) in one small spot on a high-speed rotating optical disk, a large signal enhancement is observed. It was found that a plasmon interaction generated between a silver light-scattering center and recorded small marks in the optical disk with a super-resolution near-field structure produced the large signal amplification in the spot (

Proton beam therapy (PBT) is theoretically an excellent modality for external beam radiotherapy, providing an ideal dose distribution. However, it is not clear whether PBT for prostate cancer can clinically control toxicities. The purpose of the present study was to estimate prospectively the incidence of late rectal toxicities after PBT for organ-confined prostate cancer.The major eligibility criteria included clinical Stage T1-T2N0M0; initial prostate-specific antigen level of ≤20 ng/mL and Gleason score ≤7; no hormonal therapy or hormonal therapy within 12 months before registration; and written informed consent. The primary endpoint was the incidence of late Grade 2 or greater rectal toxicity at 2 years. Three institutions in Japan participated in the present study after institutional review board approval from each. PBT was delivered to a total dose of 74 GyE in 37 fractions. The patients were prospectively followed up to collect the data on toxicities using the National Cancer Institute-Common Toxicity Criteria, version 2.0.Between 2004 and 2007, 151 patients were enrolled in the present study. Of the 151 patients, 75, 49, 9, 17, and 1 had Stage T1c, T2a, T2b, T2c, and T3a, respectively. The Gleason score was 4, 5, 6, and 7 in 5, 15, 80 and 51 patients, respectively. The initial prostate-specific antigen level was10 or 10-20 ng/mL in 102 and 49 patients, respectively, and 42 patients had received hormonal therapy and 109 had not. The median follow-up period was 43.4 months. Acute Grade 2 rectal and bladder toxicity temporarily developed in 0.7% and 12%, respectively. Of the 147 patients who had been followed up for2 years, the incidence of late Grade 2 or greater rectal and bladder toxicity was 2.0% (95% confidence interval, 0-4.3%) and 4.1% (95% confidence interval, 0.9-7.3%) at 2 years, respectively.The results of the present prospective study have revealed a valuable piece of evidence that PBT for localized prostate cancer can achieve a low incidence of late Grade 2 or greater rectal toxicities.

To study parameters that affect the tumorigenicity of L1210 lymphoma we have analyzed the structure of MHC class I antigens of this tumor. In addition this tumor was transfected with interleukin-2 (IL-2) cDNA in order to determine the effects of high concentrations of IL-2 within the tumor environment. The nucleotide sequence of the class I Kd, Dd and Ld mRNAs from this tumor showed that the encoded amino acid sequence of the corresponding antigens is normal, thus suggesting that the tumorigenicity of L1210 lymphoma is not due to defective antigen presentation to tumor-specific cytotoxic T cells. In contrast, induction of IL-2 expression by cDNA transfection led to loss of tumorigenicity of the IL-2-secreting tumor cells. However, a fraction of long-term-surviving mice developed progressively growing variant tumors that showed substantial decrease or loss of IL-2 expression. These results suggest that IL-2 secretion by tumors is suicidal but, because of tumor heterogeneity, IL-2-loss-variant tumors may arise that are able to escape the immune defenses of the host. The observed consistent loss of IL-2 expression in variant tumors implies that specific targeting of large quantities of IL-2 to tumor cells may be a valuable approach to immunotherapy of cancer. In addition we find that under specific gamma ray irradiation IL-2-secreting tumor cells lose their ability to multiply yet continue to secrete IL-2 at levels equivalent to those secreted by unirradiated cells. Such IL-2-secreting irradiated tumor cells were found to be superior immunogens in comparison to the irradiated parental tumor cells, suggesting their use as tumor vaccines.

It is well known that some metals (such as Ag) can diffuse into chalcogenides (such as Te) to produce alloys at room temperature. Using this solid–solid diffusion, we propose a technique to fabricate a near-field probe. Some basic experiments were carried out by this technique, and we obtained images on both the atomic-force microscope and scanning near-field optical microscope at the same time. Furthermore, it was found that the shading of Te is superior to that of other metals such as Ag and Al.

Proton beam therapy (PBT) is a type of radiation therapy using positively-charged particles, i. e. protons, for the treatment of malignant tumor, and is also an advanced high-technology radiotherapy using large-scale equipment, such as a synchrotron accelerator or isocentric rotational gantry systems. Since a proton beam has advantageous physical properties, i. e. Bragg peak peculiar to a charged particle beam, in formation of dose distribution as compared with mega voltage x-rays in a conventional radiotherapy, a delivery of a conformal high dose to a localized target volume is easily attained, and both improvement in local control rate and reduction of normal tissue impairment can be expected as the result. PBT is adopted mainly as a radical treatment for patients with early-stage or locally-advanced prostatic cancer, hepatocellular carcinoma, non-small cell lung cancer, or headneck malignant tumor. Moreover, the benefits of PBT may be shared not only with a pediatric patient who is easily injured and growth disturbed by even low-level irradiation of normal tissues/organs and also with an inoperable elderly patient with several medical complications. Insurance coverage in connection with its use for certain diseases is recently under discussion. This paper describes the actual status of PBT including present activities and clinical experiences at Shizuoka Cancer Center about 5 years from the start of PBT.