Der Radiologe
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The principles for estimation of the patient's radiation dose from conventional radiographic and computed tomography examinations are presented on the basis of published exposure simulation data. The relationship between absorbed dose in air, or axis dose, organ doses, and effective dose is explained. ⋯ Calculation of the effective dose from organ doses using tissue weighting factors is described. Finally, examples of dose calculation are given for a conventional radiographic and a CT examination.
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In a prospective study MR-guided laser-induced thermotherapy (LITT) of liver metastases was optimized and the clinical parameters evaluated. Seventeen patients (4 women, 13 men) with a total of 29 lesions underwent LITT in 25 sessions through 1 March 1994. Twelve of them suffered from colorectal carcinomas, 5 from other primary tumors. ⋯ Follow-up evaluation 6 months after treatment shows a significantly better response in lesions with a diameter of 20 mm or smaller, with a local tumor control rate of 66%. In lesions larger than 20 mm only a local tumor control rate of 35% could be achieved. Laser-induced thermotherapy (LITT) represents a new, minimally invasive technique for tumor destruction and a high response rate in small liver metastases.