Biomedical subjects

Masashi Kitano

Publications and source records attributed to Masashi Kitano.

6 recordsLinked to original sources

PubMed2006

Difference in rectal dosimetry between pre-plan and post-implant analysis in transperineal interstitial brachytherapy for prostate cancer.

BACKGROUND AND PURPOSE: To investigate differences in rectal dosimetry between pre-plan ultrasonography (US) and post-implant computed tomography (CT). PATIENTS AND METHODS: Subjects comprised 49 patients who underwent prostate brachytherapy using (125)I seed implants. Prescribed dose was 145Gy to the periphery of the prostate. Differences in rectal dosimetry between pre-plan US and post-implant CT analysis were evaluated. In addition, patients were divided into two groups according to timing of pre-planning (pre-plan group, n=28; intraoperative pre-plan group, n=21), and differences in rectal dosimetry between groups were assessed. RESULTS: The average of volume differences between pre-plan and post-implant analysis (pre-plan minus post-implant analysis) for all patients were follows: -0.08 cm(3) in V60 (volume of rectal wall receiving 60% of prescribed dose); -0.05 cm(3) in V70; -0.16 cm(3) in V80; -0.38 cm(3) in V90; -0.40 cm(3) in V100; -0.32 cm(3) in V110; -0.22 cm(3) in V120; -0.15 cm(3) in V130; -0.10 cm(3) in V140; -0.07 cm(3) in V150; and -0.05 cm(3) in V160. Apparent differences between pre-plan US and post-implant CT in rectal dosimetry were small. However, considering the steep curve of the relationship between tolerable volume and dose, a large actual difference should be assumed. No advantage was identified for the intraoperative pre-plan group. Safe volume to avoid proctitis tended to be smaller on ultrasonography than on CT at 1 month. CONCLUSIONS: The present work shows that direct comparison of CT analysis and pre-plan US is unfavorable due to large differences in these modalities and overestimation of tolerable volume. However, by comprehending the degree of difference, comparison of data from CT analysis with a US pre-plan may be feasible and useful for providing feedback between these modalities.

Brachytherapy↗

PubMed2006

[Cranial nerve palsies due to skull base metastases in patients with prostate cancer: a report of two cases].

Two patients with prostate cancer showed cranial nerve palsies due to skull base metastases. Case 1: A 64-year-old man had prostate cancer (T4 N0 M1, Gleason score 7, prostate-specific antigen [PSA] level 372 ng/mL) with multiple bone metastases. Seventy-seven months after initiation of therapy, he had an articulation disorder and palsy of the left side of the tongue, with 12th cranial nerve palsy. Case 2: A 75-year-old man had a prostate cancer (T3b N0 M1, Gleason score 7, PSA level 177 ng/mL) with multiple bone metastases. Sixty-six months after initiation of therapy, he had hearing loss, noise in the right ear, and dizziness, with 8th cranial nerve deficits. Magnetic resonance imaging showed low intensity in the clivus in both cases, and all over the skull in case 2. The first patient was treated with radiation therapy and intravenous steroids at an early date. His symptoms improved.

Adenocarcinoma↗

PubMed2005

[Sudden death after 125I brachytherapy in prostate cancer patient: a case report].

A management of 125I isotope is defined by medical guideline from Ministry of Health, Labour and Welfare in Japan. According to this, when the patient died within one year after 125I interstitial permanent prostate brachytherapy, we have to do autopsy and collect all implanted isotopes as soon as possible. We report here, a 70-year-old man who underwent 125I interstitial permanent prostate brachytherapy for localized prostate cancer and one month after brachytherapy the patient died of acute cerebral hemorrhage, which was unrelated to the 125I brachytherapy. Autopsy was performed and collection of migrated isotopes was extremely difficult in technically. In addition, the cost of autopsy and distance from our hospital were also problems in this case. Treatment of prostate cancer with brachytherapy has increased in Japan, and we should establish management manual for sudden death case after 125I brachytherapy.

Adenocarcinoma↗

PubMed2005

Simple technique to visualize random set-up displacements using a commercially available radiotherapy planning system.

PURPOSE: To visualize random set-up displacements in isodose distribution images, we introduce a simple technique using a commercially available radiotherapy planning system (RTP). MATERIALS AND METHODS: A distribution of set-up displacement is known to be compatible with that of a Gaussian distribution. Based on that assumption, 41 intentionally misaligned beams with 1-mm intervals were planned in the respective weights according to Gaussian distribution. "Modified" isodose distributions were then visualized using a commercially available RTP. In the next step, only two beams misaligned with one standard deviation (SD) of the Gaussian distribution were used in place of 41 beams, as a large number of beams increases the workload and is unsuitable for clinical use. Differences between the two versions of isodose distribution images were assessed visually. RESULTS: In modified dose distribution images, the edge of distribution was dull compared to normal images. These images show that the larger SD of set-up displacement dulls the edge of dose distribution. Images from two beams were not significantly different to those from 41 beams. CONCLUSION: Using this technique, the impact of random set-up displacements was effectively reflected in isodose distribution images.

Humans↗

PubMed2002

[Relation between overall treatment time and local control of early glottic laryngeal cancer: comparison of six versus five times per week].

PURPOSE: Local control probabilities of early glottic cancer were evaluated in relation to overall treatment time. MATERIALS AND METHODS: From 1971 to 1996, 162 patients with T1 or T2 glottic cancer were treated with radiation therapy. Fifty-nine patients received irradiation six times per week from 1971 to 1987, and 103 patients received irradiation five times per week from 1987 to 1996. Local control rates were calculated by the Kaplan-Meier method, and the log-rank test was used for statistical analysis. The Cox proportional hazards model was used to evaluate the significance of prognostic variables on local control. RESULTS: The 5-year local control rates were 91.8% for T1 tumors and 78.1% for T2 tumors. There was a statistically significant difference in local control rates between the two groups (p = 0.009). The overall local control rate was 86.4% for both groups, showing no statistically significant difference. Multivariate analysis showed that T stage and overall treatment time were important parameters in relation to local control. CONCLUSIONS: In early glottic cancer, there is no significant difference in local control probabilities between irradiation six times per week and five times per week.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Successful treatment of concurrent chemoradiotherapy for stage I nasal NK/T cell lymphoma: a report of two cases.

Nasal natural killer/T cell (NK/T cell) lymphoma is a rare subtype of lymphomas, being a subtype of non-Hodgkin's lymphoma with a much worse prognosis than other subtypes. One reason for this worse prognosis is that nasal NK/T cell lymphoma is resistant to standard sequential chemoradiotherapy. Thus, we adopted concurrent chemoradiotherapy using a CHOP-like regimen for treating stage I nasal NK/T cell lymphoma. Case 1 was treated with concurrent chemoradiotherapy using 41-Gy irradiation with 12 cycles of the CHOP-like regimen (THP-CVP). Case 2 was treated with concurrent chemoradiotherapy using 50-Gy irradiation with 10 cycles of THP-CVP. In both Case I and Case 2, the tumors disappeared after chemoradiotherapy. The Case 1 patient is still alive with 45 months free of relapse. The Case 2 patient is also still alive with 39 months free of relapse. These results suggest that concurrent chemoradiotherapy using a CHOP-like regimen for stage I nasal NK/T cell lymphoma provided sufficient dose intensity and may be a useful treatment option.

Adult↗