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H Tsujii

Publications and source records attributed to H Tsujii.

At least 55 records · Page 3Linked to original sources
PubMed1996

[The present and future of heavy charged particle therapy].

Introduction of heavy charged particles (protons and heavy-ions) is a promising approach in cancer treatment, permitting selective irradiation to the tumor while minimizing irradiation to the surrounding normal tissues. Additionally, the efficiency of heavy-ions will be further augmented by an increased biological effectiveness caused by high-LET components. At the University of Tsukuba, treatment with 250 MeV proton beams is being performed and, unlike other facilities in the world, successful results have been obtained in the thoraco-abdominal and pelvic tumors. Heavy-ion therapy was initiated at the University of California, and in 1993 the first heavy-ion synchrotron complex dedicated to medical use in a hospital environment was completed at the National Institute of Radiological Sciences. The carbon-ion therapy was begun in June 1994 which is expected to provide optimal results in various type of tumors. A construction of heavy-ion facility is also under consideration in Germany (GSI), Austria (AUSTRON), Italy (TERA) and Japan (Hyogo prefecture).

Forecasting↗
PubMed1996

[Present state and future of radiation therapy for pancreatic cancer].

According to a nation-wide annual report on pancreatic cancer patients in 1992, 70 percent of patients with pancreatic cancer underwent operations. Thirty percent of them, along with 10 percent of patients who did not undergo operations, underwent radiation therapy. The result of external radiation monotherapy for local advanced pancreatic cancer is so poor that the 2-year survival rate and the median survival time have been reported in some papers to be approximately 10% and at most 13 months, respectively. Our results indicated that the 1-, 2- and 3-year survival rates and the median survival time after external radiation monotherapy for local advanced pancreatic cancer were 21%, 11%, 5% and 11.3 months, respectively. The reasons for the poor results are thought to be as follows: pancreatic cancer is very malignant, invades the surrounding tissues and metastasizes distantly in its earliest stages; it is mostly adenocarcinoma resistant to radiation therapy; and the pancreas borders closely the stomach and duodenum, which are very sensitive to radiation. Therefore, charged particle radiotherapy, especially heavy ion radiotherapy, is expected to bring about advances in the field of radiation therapy for pancreatic cancer because of its excellent potential for dose distribution and biological effect.

Adult↗
PubMed1995

Proton radiotherapy for malignant melanoma of the skin.

BACKGROUND: Malignant melanoma, a tumor with reduced radiosensitivity, has been suggested to be overcome by a high-dose fractionation radiotherapy. The proton beam presents physical characteristics that enable such high-dose irradiation. OBJECTIVE: Our aim is to answer whether or not the proton beam can provide useful treatment for cutaneous melanoma. METHODS: Five primary melanomas (4 acral lentiginous and 1 superficial spreading type) and 3 metastatic lymph nodes of 3 different patients were irradiated using the proton beam with a total dose of around 100 Gy fractionated into single doses of approximately 10 Gy. RESULTS: All the macular lesions and a tumor lesion of primary melanoma disappeared completely, and other tumor lesions regressed by 80-90%. The 3 metastatic lymph nodes also regressed by 50-90%. No severe radiation-related complication occurred. CONCLUSION: Proton radiotherapy may prove to be a useful therapeutic modality for the management of cutaneous malignant melanoma.

Aged↗
PubMed1995

Effects of gonadotropin administration on follicular growth and in vitro fertilization in female hypogonadal mice.

Folliculogenesis in female hypogonadal (hpg) mice was examined after treatment with exogenous gonadotropins. The female mutant mice were characterized by a deficiency of hypothalamic gonadotropin-releasing hormone (GnRH), leading to the absence of estrus and ovulation. Gonadotropin administration induced resumption of gonadal development and vaginal opening. The follicles that developed with gonadotropin treatment were very similar to those in normal littermates. The oocytes from hpg mice showed the capacity for fertilization and development to produce viable young after in vitro fertilization and embryo transplantation. Thus, the combination of the exogenous gonadotropin administration, in vitro fertilization and embryo transfer method appear to be helpful to breed mutant hpg mice efficiently.

Animals↗
PubMed1995

[Progress in particle-beam radiation therapy].

The advantages of particle-beam radiation therapy include its radiobiologic properties and spatial dose distribution. With the recent progress in diagnostic imaging, the cumulative knowledge of radiation biology, and the development of a 3-dimensional treatment planning system, particle-beam radiation therapy could prove clinically effective. Local control of tumors is an essential for the cure. Particle-beam radiation therapy has the potential to provide better local tumor control.

Humans↗
PubMed1995

[Dose-volume histogram analysis of patients with hepatocellular carcinoma regarding changes in liver function after proton therapy].

Seventy-five patients with hepatocellular carcinoma were treated with proton beams from 1983-1993 at the Proton Medical Research Center, University of Tsukuba. For the purpose of confirming the feasibility of proton therapy for hepatocellular carcinoma, we investigated the influence of proton therapy on liver function and also tried to evaluate the possibility of optimization using dose-volume histogram (DVH) analysis. The results indicated that proton therapy did not cause clinically symptomatic damage in liver function and the only notable change after proton therapy was the transient increase of transminase. DVH analysis showed that this transient increase of transaminase was well correlated to the normal tissue complication probability (NTCP). These results indicate that localized high dose radiation using proton beams is feasible for the treatment of liver cancers and optimization of this treatment may be possible using DVH analysis.

Adult↗
PubMed1994

A new, effective, and safe therapeutic option using proton irradiation for hepatocellular carcinoma.

BACKGROUND/AIMS: Conventional radiation is almost useless for hepatocellular carcinoma (HCC) because of the severe adverse effects of the irradiation to the accompanying liver cirrhosis. In contrast, the proton beam has Bragg peak, which limits distribution of the beam. The aim of this study was to prove the usefulness of proton irradiation for HCC. METHODS: The proton irradiation was performed in 32 nodular lesions in 24 patients with HCC who had unresectable tumors or serious complications; the proton irradiation was performed either as monotherapy (15 lesions) or as combination therapy to insufficient Lipiodol-targeted chemotherapy (Kodama Co. Ltd., Tokyo, Japan) (17 lesions). The energy was 250 MeV, and 50-87 Gy (76.5 +/- 9.5, mean +/- SD) in total was irradiated for a time period of 17-69 days. RESULTS: After 1 year, size reduction was seen in 12 out of 13 lesions (92%) in the monotherapy group and 9 out of 9 lesions (100%) in the combination therapy group; after 2 years, size reduction was seen 4 out of 5 lesions (80%) in the monotherapy group and 5 out of 5 lesions (100%) in the combination therapy group. Local tumor control has being assured for 2 years of the observation, which is continuing for another 2 years. None of the patients have experienced any serious adverse effects. CONCLUSIONS: These results show that proton irradiation is a new, safe, and effective therapeutic option in cases of HCC, even in patients with unresectable tumors or those with serious complications.

Aged↗
PubMed1994

Precise positioning of intracranial small tumors to the linear accelerator's isocenter, using a stereotactic radiotherapy computed tomography system (SRT-CT).

RT-CT was developed as a simulator using CT scan for radiotherapy. Following three-dimensional treatment planning using CT images, the treatment center and treatment fields are projected to the patients' surface by laser beam on the C arm. The prototype had an accuracy of 3 mm which was equivalent to conventional X-ray simulators but was not adequate for use in stereotactic radiotherapy. A new RT-CT system was developed to have a precise localization capability for stereotactic radiotherapy. Using this stereotactic RT-CT (SRT-CT) after three-dimensional planning, the treatment center is projected to the stereotactic frame automatically. In this study, the values of the x, y and z coordinates of the target center determined by SRT-CT are compared with those determined by the traditional method using CT localizing plates. The discrepancies were within 1.0 mm in 90% and 1.5 mm in 100% of 30 measurements in 16 patients. The disadvantages of SRT-CT may be that the accuracy of localization depends on the quality of calibration of laser beams. The traditional CT localizing method has superiority over SRT-CT because of its solid coordinates but its accuracy is vulnerable to alignment of CT fiducial marker plates. Therefore, the SRT-CT and traditional CT localizing methods would be complementary to each other for precise localization.

Brain Neoplasms↗
PubMed1994

Proton radiotherapy of skin carcinomas.

At the Proton Medical Research Center, University of Tsukuba, we performed a pilot study of proton-beam radiotherapy in 12 patients with the following types of carcinoma: Bowen's disease (4), oral verrucous carcinoma (5), and squamous cell carcinoma (3). They received total doses of 51-99.2 Gy in fractions of 2-12.5 Gy. All of the tumours responded well to the treatment. All four lesions of Bowen's disease, three of the five oral verrucous carcinomas, and the three squamous cell carcinomas completely regressed following irradiation. Two squamous cell carcinomas recurred during the follow-up period. One recurrent squamous cell carcinoma was successfully treated by a salvage surgical operation, and in the other case the patient refused further therapy. In two verrucous carcinomas there was 90% regression of tumour volume. No severe radiation-related complication occurred. As proton radiotherapy produces good local tumour control without significant morbidity to the surrounding normal tissues, it may prove to be a useful therapeutic modality for the treatment of skin carcinomas.

Aged↗
PubMed1994

Radiation tolerance of the liver in relation to the preserved functional capacity.

The radiation tolerance of the liver was investigated in 12 patients, 11 of them with liver cirrhosis, treated for hepatocellular carcinoma by partial liver irradiation with doses between 50 and 77 Gy. The tolerance was assessed by the complication probability (Lyman's model), which concerned the injured tissue itself, and by a prediction score used for postsurgical liver failure, which concerned the preserved functional capacity, assuming that the > or = 30 Gy volume was equivalent to the resected volume. The prediction score corresponded better with the observed risk of fatal liver failure than the complication probability. The liver volume after radiotherapy correlated largely with the untreated volume and the low-dose volume. Thus the preserved functional capacity gives a better expression of the radiation tolerance than direct measures of the extent of injured tissue.

Aged↗
PubMed1994

Determination of apolipoprotein E in high density lipoprotein fraction by immunofixation method and turbidimetric immunoassay after precipitation.

Apolipoprotein E (apoE) in high density lipoprotein (HDL) fraction (HDL-fr) was determined by the immunofixation method and turbidimetric immunoassay (TIA) after precipitation with phosphotungstic acid/MgCl2 in normolipidemic control subjects and patients with type IV hyperlipemia and hyper HDL-cholesterolemia. Immunofixation assay revealed two major bands of apoE in whole serum: one in the alpha-area and the other in the pre beta-area. ApoE in alpha-area (alpha-apoE) was identical to alpha-apoE in HDL-fr separated by ultracentrifugation but not to alpha-apoE in HDL-fr separated by precipitation (pHDL-fr). alpha-ApoE in pHDL-fr lacked the slower area of the band. Agarose column chromatography and gradient gel electrophoresis indicated that alpha-apoE belongs to early fractionated HDL, and that the precipitatable alpha-ApoE belongs to the higher molecular size HDL alpha-ApoE (%) estimated by immunofixation showed a strong positive correlation with apoE (%) in pHDL-fr. ApoE (%) in pHDL-fr was higher in case of hyper HDL-cholesterolemia and lower in type IV hyperlipemia than in controls, and was inversely correlated with serum triglycerides (TG) and positively with HDL-cholesterol (especially HDL2-cholesterol) in these subjects. It is suggested that the variation of apoE in pHDL-fr depends on the level of HDL2. Also, it may be suggested that apoE in pHDL-fr and precipitatable alpha-apoE belong to low and high molecular HDL2, respectively, and that apoE content in these particles is correlated with HDL2.

Adult↗
PubMed1994

Preliminary results of bladder-preserving therapy with definitive radiotherapy and intraarterial infusion of chemotherapy.

PURPOSE: For management of muscle-invading bladder cancer (clinical stages T2 to T4), combined treatment of definitive radiotherapy (RT) and intraarterial (IA) administration of chemotherapy was carried out for local cure and bladder preservation. METHODS AND MATERIALS: Between 1987 and 1990, a pilot study (Protocol-1) was initially conducted in 16 patients to investigate the efficacy of chemoradiotherapy where RT was combined with TURB and continuous IA infusion of cisplatin. We then performed a regimen of possible bladder-preservation treatment (Protocol-2) in which 19 patients were treated with combination of TURB, full-dose RT and one-shot IA infusion of cisplatin and methotrexate. In RT small pelvis irradiation was performed with x-rays followed by proton beam boost irradiation to the original tumor site. RESULTS: Among patients treated on Protocol-1, a tumor-free bladder was observed in 50% (2/4) after 50-76 Gy but only 8% (1/14) after 30-40 Gy. In this regimen, planned cystectomy was performed in 10 patients and 13 patients (81%) are alive. Among 19 patients treated on Protocol-2, 17 patients (89%) are alive and 13 patients (68%) retained intact bladders without any recurrence. There were 3 cystectomies performed because of persistent tumors. Using a conformal mode of proton beam irradiation, a total dose of 60-80 Gy was safely administered with acceptable morbidities. CONCLUSION: In the light of good complete response and survival rates achieved in the patients treated on Protocol-2, the combined treatment of definitive RT and IA administration of chemotherapy is considered as an effective bladder-preserving strategy.

Aged↗
PubMed1994

[Progress in heavy particle radiotherapy].

In recent years, new types of ionizing radiations have been used as an attractive modality in cancer treatments. Low LET radiation such as protons and helium ions has the advantage of a high physical selectivity of irradiation. Clinical results have confirmed that they are of benefit in certain types of cancer. High LET particles such as fast neutrons, heavy ions (carbon, neon) and negative pions possess higher radiobiological effects (RBE). Moreover, the latter two particles have an advantage of improved dose distribution. The clinical indications for protons are those located in close vicinity to the critical normal organs, and those for fast neutrons are relatively superficial tumors. Further studies are needed to determine indications for pions. The available clinical experience in selected tumors with protons, pions and fast neutrons justifies the heavy-ion therapy programs. Successful results are anticipated from HIMAC (Heavy ion medical accelerator in Chiba) which is a dedicated facility for heavy-ion therapy.

Forecasting↗
PubMed1994

Proton beam therapy for patients with esophageal carcinoma.

Fifteen patients with esophageal carcinoma (superficial, six cases; advanced, nine cases) were treated with 250 MeV proton beam irradiation with or without external x-ray irradiation (12 MV linear accelerator) from October, 1985, to May, 1991. Eleven patients were initially treated with x-ray at doses of 16.2-50.4 (mean 42.5) Gy, followed by proton beam at doses of 30.0-52.9 (mean 37.6) Gy. The other four patients were treated with proton beams alone at total doses of 75.0-88.5 (mean 81.4) Gy. The mean total dose for the 15 patients was 80.4 Gy. As a result, the primary tumor lesions of all 15 patients disappeared and complete responses were obtained. Approximately four to five months later, nine of the 15 patients developed esophageal ulcer formations at the circumferences of their primary lesions. The ulcerations were healed, however, by conservative management. There was no evidence of local recurrence throughout the observations on six cases of superficial carcinoma. Among nine advanced carcinoma patients, three relapsed into esophageal carcinoma. Recurrences were observed eight, 16 and 44 months, respectively, after the treatment. Ten of the 15 patients died, but eight died of other diseases. Three of four cases at autopsy did not show any cancer cells in irradiated primary lesions. Four of the 15 patients lived for over five years. The results suggest that a high dose of irradiation delivered by a well-defined proton field could result in improved local control and long-term survival in esophageal carcinoma without undue risk of injury to primary and adjacent organs.

Aged↗
PubMed1993

Autoimmunity during alpha-interferon therapy for chronic hepatitis C.

One hundred twenty-five patients with chronic hepatitis C were treated with natural IFN alpha or recombinant IFN alpha-2a, daily doses of 3 MU or 9 MU, respectively. IFNs were given 6 times a week for the first 2 weeks followed by thrice weekly administration for 12 weeks or more. ANA, TMA, AMA and anti-DNA antibody newly developed in 8, 1, 2 and 1 patient, respectively. Furthermore, we encountered some cases in which underlying autoimmune disorders were thought to be exacerbated by IFNs. It is important to pay sufficient attention to the development of autoimmune diseases in IFN therapy for chronic hepatitis C.

Adult↗