[The 60th Annual Scientific Congress: Symposium Filmless PACS: now and future].
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Computer Security↗
Biomedical subjects
Kaoru Okajima
Publications and source records attributed to Kaoru Okajima.
The relationship between coronary artery calcification detected by non-gated multi-detector CT in patients with suspected ischemic heart disease and myocardial ischemia detected by thallium exercise stress testing.
OBJECTIVE: To examine whether we could predict myocardial ischemia when coronary artery calcification is detected by non-gated multidetector CT in patients with suspected ischemic heart disease. METHODS: Eighty-three patients suspected of having ischemic heart disease (55 men, 28 women; age range 36-83 years; mean age 68 years) underwent multidetector CT and T1-201 single photon emission computed tomography. Prediction of myocardial ischemia by coronary arterial calcification detected on CT was evaluated by comparing the coronary artery territories that showed calcification with the area of myocardial ischemia determined by SPECT. The sensitivity, specificity, positive predictive value, and negative predictive value of multidetector CT for predicting myocardial ischemia were calculated. Coronary angiography was also examined and compared with multidetector CT. Risk factors, including hypertension, smoking, hyperlipidemia, diabetes, and family history, were compared for evidence of coronary artery calcification detected by multidetector CT and myocardial ischemia detected by thallium nuclear scans. RESULTS: For analysis by patients, the sensitivity, specificity, positive predictive value, and negative predictive value of coronary artery calcification for myocardial ischemia detection were 65, 63, 56, and 71%, respectively. Similarly, for analysis by coronary arterial territories, those values were 56, 77, 41 and 86%, respectively. Coronary stenosis on CAG was also related to the ischemia determined by SPECT and calcification on multidetector CT. Ischemia was better influenced by risk factors than was coronary arterial calcification. CONCLUSIONS: For analysis by coronary arterial territories, the specificity and negative predictive value of coronary arterial calcification seen by multidetector CT are relatively high.
Adult↗
Comparison of outcomes between overlapping structure-based and non-overlapping structure-based optimization for simultaneous integrated boost IMRT for malignant gliomas.
BACKGROUND: Intensity-modulated radiotherapy (IMRT) can deliver different doses to two target volumes with high conformity. The purpose of the present study was to compare outcomes provided by two different optimization methods, overlapping structure-based and non-overlapping structure-based methods, for simultaneous integrated boost (SIB)-IMRT for malignant gliomas. METHODS: Treatment plans for three glioblastomas and one anaplastic astrocytoma were analyzed in the present study. The planning protocol was to deliver 70 Gy/28 fractions (fr) to the gross tumor volume (GTV) and 56 Gy/28 fr to the surrounding edema. Two different optimization methods were tested for optimizing dose distribution to the GTVand the surrounding edema. One method was the "including method", an overlapping structure-based (GTV and the clinical target volume [CTV]) optimization method. The other method was the "annulus method", a non-overlapping structure-based (GTV and the subtracted volume) optimization method. Dosimetric indexes derived from dose-volume histograms (DVHs) were used for the analysis. RESULTS: There was no significant difference between the two methods in the mean doses of the target volumes and the doses delivered to the 5% or 95% target volumes (D05 or D95). The mean dose to the brain by the including method was significantly higher than that delivered by the annulus method (P = 0.0001). The D05 of the brain showed no significant difference between the two methods. CONCLUSION: The two optimization methods provided comparable dose distributions within the target volumes and normal brain.
Brain Neoplasms↗
Concurrent chemotherapy and radiotherapy with low-dose Cisplatin for nasopharyngeal carcinoma.
Eighty-one patients with nondisseminated nasopharyngeal carcinoma consecutively treated between January 1977 and December 1998 were analyzed to evaluate whether a concurrent adjunction of low-dose cisplatin enhances the outcome of definitive radiotherapy. Ninety-eight percent (n = 79) of the cases were ranked as stage III/IV according to the 1987 Union International Contre le Cancer staging criteria. Patients treated before 1987 and treated after 1988 were mainly managed by radiotherapy alone (historical group: n = 48) and concurrent chemoradiotherapy with relatively low-dose cisplatin (CCRT group: n = 33), respectively. The locoregional failure-free survival rate of the CCRT group was significantly better than that of the historical group (72.8% vs. 35.9% at 5 years, p = 0.0041). However, multivariate analysis identified only the total dose and the T-stage as significant independent factors for locoregional control. No difference was observed on overall, disease-specific, and distant failure-free survival between the two groups. The results of the present study suggest that concurrent adjunction of low-dose cisplatin will not improve the outcome of definitive radiotherapy for nasopharyngeal carcinoma. Full-dose concurrent chemoradiotherapy, as well as the appropriate dose escalation for better locoregional control, will be mandatory to achieve better survival.
Adult↗