Biomedical subjects

Toshihiko Inoue

Publications and source records attributed to Toshihiko Inoue.

43 records · Page 3Linked to original sources

PubMedDate not supplied

High dose rate endovascular brachytherapy in aorto-iliac lesion for the prevention of restenosis.

This study examined the applicability of endovascular brachytherapy to larger del arteries such as the abdominal aorta and iliac artery. Endovascular brachytherapy using an Ir-192 HDR source was administered 11 times to nine patients who had undergone percutaneous transluminal angioplasty (PTA) between 1995 and 1999. The follow-up lasted 13 to 55 months after treatment (median, 24 months). Eight of the 11 lesions have been controlled so far. Although one case developed thrombus inside the stent five months later, recanalization was achieved by means of retreatment. One patient who underwent low-dose irradiation (6 Gy) without stent implantation showed restenosis five months after treatment. We used a centering catheter that did not block the blood stream for exact centering of the radiation source in larger vessels such as the abdominal aorta. Although endovascular brachytherapy is a promising and safe procedure, careful follow-up is needed to detect untoward reactions such as thrombosis.

Aged↗

PubMedDate not supplied

CyberKnife stereotactic irradiation for metastatic brain tumors.

BACKGROUND: The CyberKnife provides a new technique for performing frameless stereotactic irradiation. So far, few reports have been published on clinical outcomes obtained with the CyberKnife. This report summarizes our clinical experience with CyberKnife irradiation for metastatic brain tumors. MATERIALS AND METHODS: Seventy-seven lesions (48 patients) were evaluated and analyzed, and 66 lesions in 41 patients were treated with stereotactic radiosurgery (SRS). The prescribed dose was 9 to 30 Gy. RESULTS: Freedom from progression of the tumors was more likely with a prescribed dose of at least 24 Gy than with one of less than 20 Gy (p=0.0244; log-rank test). The CR (complete response) rate was significantly higher when D99 was at least 24 Gy (p=0.0045). There were no severe side effects. CONCLUSION: Stereotactic irradiation with the CyberKnife for metastatic brain tumors is effective and safe. D99 should be at least 24 Gy for CyberKnife SRS treatment.

Brain Neoplasms↗

PubMedDate not supplied

Monte Carlo calculation of depth doses for small field of CyberKnife.

PURPOSE: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. MATERIALS AND METHODS: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mm diameter) and three small fields (30, 15, and 5 mm diameter) were compared with those measured with a diamond detector. RESULTS AND DISCUSSION: The MC-calculated and measured %dd-curves for the 60 mm diameter field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mm diameter field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. CONCLUSION: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.

Humans↗

PubMedDate not supplied

Influence of in vitro radiation on changes in nitric oxide in rat macrophages and smooth muscle cells.

We examined changes in nitric oxide (NO) levels resulting from irradiation of rat macrophage (RAM) and smooth muscle cells (SMC) in medium. Irradiation did not alter the NO concentration in the medium of either cell line. However, irradiation of 5 and 20 Gy enhanced the concentration of NO induced by lipopolysaccharide (LPS) in the medium containing RAM. Furthermore, 20 Gy of irradiation suppressed NO production induced by interferon-gamma in the RAM medium. Radiation seemed to enhance NO production more than that caused by Interleukin 1-beta only in the medium containing SMC. Next, mRNA levels of inducible NO synthase (NOS) were examined in RAM by Northern blotting following irradiation. Five Gy of irradiation did not generate iNOS mRNA expression, but did enhance iNOS piRNA expression induced by LPS, while 20 Gy suppressed the expression level of iNOS mRNA more than 5 Gy. This leads to the conclusion that radiation stimulation induced NO production through indirect action on the macrophage.

Animals↗

PubMedDate not supplied

Treatment results of radiotherapy with or without surgery for posterior pharyngeal wall cancer of oropharynx and hypopharynx: prognostic value of tumor extension.

PURPOSE: We have been treating posterior pharyngeal wall cancer of the oropharynx and hypopharynx with external radiotherapy according to our policy reported in the 1970s. MATERIALS AND METHODS: Between 1968 and 1995, 51 patients were treated. Treatment policy was decided on the basis of the treatment response after 40 Gy of radiotherapy. Thirty-six good responders were treated with radical radiotherapy, eight poor responders received radical surgery, and the other seven patients could not receive radical treatment because of tumor or patient factors. RESULTS: The 5-year local control and cause-specific survival rates were 56% and 48% for all 51 patients. The 5-year local control rate was 52% for radical radiotherapy. Tumors limited to the posterior wall showed better treatment results (76% for both local control and cause-specific survival) than tumors involving the postcricoid area (0% and 10%). CONCLUSION: Radiotherapy for carefully selected patients dependent on response after 40 Gy of radiotherapy is a useful policy. Tumor extension is an important prognostic factor.

Adult↗

PubMedDate not supplied

Radiotherapy for localized hormone-refractory prostate cancer in Japan.

BACKGROUND: The role of radiotherapy for patients with localized hormone-refractory cancer has not been well documented. MATERIALS AND METHODS: The Patterns of Care Study in Japan examined the records of 311 patients with prostate cancer treated with radiotherapy during the period 1996--1998. Of them, 61 patients (19.6%) with regionally localized hormone-refractory cancer were selected. Local progression or biochemical failure was observed after a median duration of 15.9 months of androgen deprivation. At the time of radiotherapy, 49 patients (80.4%) had T3-4 tumors and 15 (26.8%) had regional lymph node metastases. External beam radiotherapy was performed with a median total dose of 60 Gy. RESULTS: Although distant metastases or regional lymph node metastases were seen in 22 patients (36.1), local progression was observed in one patient (1.6%). The five-year overall and progression-free survival rates were 51.6% and 43.5%, respectively. CONCLUSION: Radiotherapy had an excellent local control rate for hormone-refractory cancer.

Aged↗

PubMedDate not supplied

High-dose-rate interstitial brachytherapy for mobile tongue cancer: influence of the non-irradiated period.

BACKGROUND: It has been demonstrated that the outcome of primary radiotherapy in squamous cell carcinomas of the head and neck is strongly influenced by overall treatment time. The purpose of this study was to evaluate the results of high-dose-rate (HDR) interstitial brachytherapy (ISBT) for early mobile tongue cancer and to examine whether the non-irradiated period affected treatment results. MATERIALS AND METHODS: Seventy-one patients with early mobile tongue cancer (T1-T2N0M0) were treated with HDR ISBT alone. The total dose was 54-60 Gy/9-10 fractions/5-9 days. All patients were classified into 4 groups: R0, maximum non-irradiated period (NIP) was less than 24 h (n=16); R1, maximum NIP was from 24 to 48 h (n=24); R2, maximum NIP was from 48 to 72 h (n=26); R3, maximum NIP was from 72 to 96 h (n=5). RESULTS: The 3-year local control rate was 94% in R0, 83% in R1, 85% in R2 and 100% in R3. The 3-year overall survival rate was 84% in R0, 92% in R1, 71% in R2 and 80% in R3. There was no significant difference in the local control rate, overall survival rate, or complications among the 4 groups. CONCLUSION: In HDR ISBT for early mobile tongue cancer, the non-irradiated period did not affect the treatment results or complications.

Adult↗