[Comparison of dosimetric properties of 15-MV-photons and 14-MeV-neutrons in external stereotaxic convergence therapy]. / Vergleich der dosimetrischen Eigenschaften von 15-MV-Photonen und 14-MeV-Neutronen bei der externen stereotaktischen Konvergenztherapie.

Dosimetric properties for stereotaxic convergent beam therapy techniques with small field sizes have been investigated as well as for the linear accelerator Mevatron 77 as for the neutron generator KARIN. Additionally we also measured the dose distribution of single plane rotational therapy. As an indication of quality we calculated the V50 ratio as V50 = (F50-F90)/F90 and the corresponding V20 values. For the single plane irradiation there is a considerable difference in dose distribution in favour of photons. V50 (axial) amounts to 1.77 for photons and to 2.7 for neutrons. For the convergential non coplaner arc-therapy using nine plans there is nearly no difference in the high dose region including the 50%-isodose. V50 (axial): 1.16 and 1.6 respectively; (frontal) 1.36 and 1.35 respectively. Regarding to physical dose distributions our results indicate, that 14-MeV neutrons are suitable for high dosed stereotactic single irradiations.

Three group treatments for reduction of speech anxiety among students.

Conditions of group systematic desensitization (n = 8), group flooding (n = 7), and a group discussion-placebo control treatment (n = 4) were employed to reduce anxiety about public-speaking in university students. Three 90-min. sessions were provided. Pre- and posttreatment assessments employed self-report and behavioral measures. The desensitization group showed significant pre- to posttreatment change across all self-report measures, whereas the flooding and control groups showed similar improvement on only one such measure. No group showed significant improvement on the behavioral measure. Groups did not exhibit significant intergroup differences in improvement on any measure.