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E Walther

Publications and source records attributed to E Walther.

47 records · Page 3Linked to original sources
PubMed1979

[Study on the dose distribution of 8-MeV bremsstrahlung in mantle field techniques (author's transl)].

The dose distribution within the patient was studied with 8-MeV bremsstrahlung from a linear accelerator during mantle field irradiation using molded shielding blocks. Doses and dose distributions in the different layers of a modified Alderson phantom were measured by means of film dosimetry and related to the dose in the central ray beam at the middle of the body. Dose distribution within unshielded regions perpendicular to the central ray beam generally being relatively homogeneous, the highest relative doses, amounting to ca. 115%, are found in the region of the mandibular angle and in the supraclavicular region; the dose to superficial lymph nodes at the supraclavicular region reaches 100% of the dose in the central ray beam. As a cause for these important doses near the surface of the body are discussed the extension of mantle fields as well as the increased exit dose of the opposed field and the oblique incidence of radiation.

Humans↗
PubMedDate not supplied

Echinacea root extracts for the prevention of upper respiratory tract infections: a double-blind, placebo-controlled randomized trial.

OBJECTIVE: To investigate the safety and efficacy of 2 extracts of echinacea for preventing upper respiratory tract infections. DESIGN: Three-armed, randomized, double-blind, placebo-controlled trial. SETTING: Four military institutions and 1 industrial plant. PARTICIPANTS: Three hundred two volunteers without acute illness at time of enrollment. INTERVENTIONS: Ethanolic extract from Echinacea purpurea roots, Echinacea angustifolia roots, or placebo, given orally for 12 weeks. MAIN OUTCOME MEASURE: Time until the first upper respiratory tract infection (time to event). Secondary outcome measures were the number of participants with at least 1 infection, global assessment, and adverse effects. RESULTS: The time until occurrence of the first upper respiratory tract infection was 66 days (95% confidence interval [CI], 61-72 days) in the E angustifolia group, 69 days (95% CI, 64-74 days) in the E purpurea group, and 65 days (95% CI, 59-70 days) in the placebo group (P = .49). In the placebo group, 36.7% had an infection. In the treatment groups, 32.0% in the E angustifolia group (relative risk compared with placebo, 0.87; 95% CI, 0.59-1.30) and 29.3% in the E purpurea group (relative risk compared with placebo, 0.80; 95% CI, 0.53-1.31) had an infection. Participants in the treatment groups believed that they had more benefit from the medication than those in the placebo group (P = .04). Adverse effects were reported by 18 subjects in the E angustifolia group, 10 in the E purpurea group, and 11 in the placebo group. CONCLUSION: In this study a prophylactic effect of the investigated echinacea extracts could not be shown. However, based on the results of this and 2 other studies, one could speculate that there might be an effect of echinacea products in the order of magnitude of 10% to 20% relative risk reduction. Future studies with much larger sample sizes would be needed to prove this effect.

Adult↗