[Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions]. / Exposition der Augenlinse des Untersuchers und Effizienz der Strahlenschutzmittel bei fluoroskopischen Interventionen.

PURPOSE: Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. MATERIALS AND METHODS: A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. RESULTS: The exposition of the lens of about 110 to 550 µSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25°LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. CONCLUSION: The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently.

Lossless state detection of single neutral atoms.

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 µs. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.

Low trough levels of tipranavir in a combination antiretroviral therapy of tipranavir/ritonavir and tenofovir require therapeutic drug monitoring.

The new non-peptidic protease inhibitor tipranavir is used boosted with ritonavir in a 500/200 mg bid scheme. Multiple drug interactions are described for both drugs because of their different action in CYP450 3A4 and p-glycoprotein. In this retrospective analysis of 22 patients during therapy with tipranavir/ritonavir (TPV) 500 mg/200 mg bid, we found significantly decreased TPV-trough levels in combination with tenofovir (15.32+/-5.22 microg/ml) in comparison to TPV trough levels without tenofovir (20.21+/-14.87 microg/ml). Therapeutic drug monitoring of TPV is recommended.

High performance liquid chromatographic method for the determination of HIV-1 protease inhibitor tipranavir in plasma of patients during highly active antiretroviral therapy.

A new high-performance liquid chromatographic method for the determination of tipranavir in human plasma is described. Quantitative recovery following liquid-liquid-extraction with diethylether from 100 microl of human plasma was achieved. Subsequently, the assay was performed with 67 mM potassium dihydrogen phosphate-acetonitrile as a mobile phase, a Phenomenex C 18 column and UV detection at 255 nm. Linear Standard curves were obtained for concentrations ranging from 2.5 to 400 microg/ml. The calculated intra- and inter-day coefficents of variation were below 7%.