Background: We prospectively reviewed response rates, local control, and side effects after nonfractionated stereotactic high single-dose body radiation therapy for lung tumors.

The accuracy of quantifying the degree of vascular stenosis with color Doppler flow imaging (7.5-MHz, linear array system) was determined in an experimental study carried out on six concentric and five eccentric model stenoses (cross-sectional area reduction, 13.4%-93.8%). The measurements were made with use of pulsatile flow at four different flow rates (70.8-339.0 mL/min). The degree of stenosis was calculated from the ratio of prestenotic to intrastenotic flow velocity. The most exact measurement of the degree of stenosis could be achieved with Doppler spectral analysis by determining the maximum peak systolic velocity (r = .994, y = 0.98x - 3.2). With the velocity values derived only from the color-coded image, it was also possible to find the most exact degree of stenosis (r = .995, y = 0.99x - 2.9). For quantification of stenosis, pre- and intrastenotic Doppler spectral analysis is no longer necessary if the stenosis can be imaged sufficiently with color Doppler.

With reference to radiosurgery of the liver, we describe techniques designed to solve the methodological problem of striking targets subject to respiratory motion with the necessary precision. Implanting a gold marker in the vicinity of the liver tumor was the first step in ensuring the reproducibility of the isocenter's position. An 18-karat gold rod measuring 1.9 × 3 mm was implanted approximately 2 cm from the edge of the tumor as this was displayed in the spiral, thin-slice CT with contrast media. Both the implantation of the marker and the required, CT-controlled biopsy of the liver tumor can be achieved simultaneously with the same puncture needle. The efficiency of high-frequency jet ventilation (HFJV) in neutralizing the targeted organ's respiratory motion during stereotactic single-dose irradiation was evaluated. The procedure was carried out on ten patients without any complications. In the time between treatment planning and irradiation (3 days), no significant marker migration was observable. In all cases, the gold marker (volume: 7.5 mm³) was readily observable in the treatment beam using portal imaging. HFJV provided reliable immobilization. The liver motion in each anesthetized patient was limited to under 3.0 mm in all directions. Thus, the correct field settings and target reproducibility were able to be analyzed and documented during the irradiation. The combination of marker and HFJV enables the determination of stereotactic coordinates directly related to the liver itself and, in this way, stereotactic radiation treatment of liver tumors is freed from the uncertainties involved in orientation to bony landmarks, in respiratory motion, and in changes of position in the stereotactic body frame. The method is feasible and can improve the accuracy of stereotactic body radiation therapy.

Compared to analogous techniques there is no loss of image information when employing digital selenium radiography in chest x-rays. On the contrary, new assessment criteria may be gained. We conclude that digital selenium radiography offers diagnostic advantages in chest x-ray examination.

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