Towards a Field-Based Bayesian Evidence Inference from Nested Sampling Data.

Nested sampling (NS) is a stochastic method for computing the log-evidence of a Bayesian problem. It relies on stochastic estimates of prior volumes enclosed by likelihood contours, which limits the accuracy of the log-evidence calculation. We propose to transform the prior volume estimation into a Bayesian inference problem, which allows us to incorporate a smoothness assumption for likelihood-prior-volume relations.

Causal, Bayesian, & non-parametric modeling of the SARS-CoV-2 viral load distribution vs. patient's age.

The viral load of patients infected with SARS-CoV-2 varies on logarithmic scales and possibly with age. Controversial claims have been made in the literature regarding whether the viral load distribution actually depends on the age of the patients. Such a dependence would have implications for the COVID-19 spreading mechanism, the age-dependent immune system reaction, and thus for policymaking.

Machine intelligence decrypts β-lapachone as an allosteric 5-lipoxygenase inhibitor.

Using machine learning, targets were identified for β-lapachone. Resorting to biochemical assays, β-lapachone was validated as a potent, ligand efficient, allosteric and reversible modulator of 5-lipoxygenase (5-LO). Moreover, we provide a rationale for 5-LO modulation and show that inhibition of 5-LO is relevant for the anticancer activity of β-lapachone.

Exposure of treating physician to radiation during prostate brachytherapy using iodine-125 seeds: dose measurements on both hands with thermoluminescence dosimeters.

Background And Purpose: Only sparse reports have been made about radiation exposure of the treating physician during prostate seed implantation. Therefore, thermoluminescence dosimeter (TLD) measurements on the index fingers and the backs of both hands were conducted.

Material And Methods: Stranded iodine-125 seeds with a mean apparent activity of 27.

[Results of quality controls for individual doses to patients in radiation oncology].

Background: Along with the treatment equipment and the planning system the individual doses to the patient also have to be part of quality assurance. To make sure that the dose application to the patient is correct, a two-step concept is used: the check of the planned dose and the in vivo dosimetry.

Methods: In contrast to the treatment planning where the necessary parameters for a desirable dose distribution and dose are determined in the target volume, the dose in the ICRU point is calculated from the individual setup parameters.

[MLC positioning checks and calibration with a portal imaging system].

For checking the leaf positions of a MLC (Multi Leaf Collimator) images are acquired with an EPID (Electronic Portal Imaging Device) and then evaluated with a programme (MLC check) developed in-house. During image acquisition a Perspex tray with two metal markers of known position (in the radiation field) is inserted in the satellite tray holder. After determination of the marker positions within the image coordinate system, the image can be transformed to the radiation field coordinate system.

Long-term outcomes after intracoronary Beta-irradiation for in-stent restenosis in bare-metal stents.

Objective: We sought to characterize the long-term outcomes of patients undergoing intracoronary brachytherapy using Beta- irradiation (Beta-BT).

Background: Beta-BT is effective in reducing angiographic restenosis as well as target vessel revascularization (TVR) in patients with in-stent restenosis (ISR) after bare-metal stenting (BMS).

Methods: 81 consecutive patients undergoing Beta-BT for ISR (irradiated length 32 [32-54] mm) after BMS in native vessels (n = 79) or saphenous vein grafts (n = 2) between 2001 and 2003 were followed.

[Determination of organ doses and effective doses in radiooncology].

Background And Purpose: With an increasing chance of success in radiooncology, it is necessary to estimate the risk from radiation scatter to areas outside the target volume. The cancer risk from a radiation treatment can be estimated from the organ doses, allowing a somewhat limited effective dose to be estimated and compared.

Material And Methods: The doses of the radiation-sensitive organs outside the target volume can be estimated with the aid of the PC program PERIDOSE developed by van der Giessen.

[Shielding during dental X-ray examinations. Effectiveness of radiation protection measures for patients during X-ray examinations].

During dental X-ray examinations, lead rubber shields such as neck protections or half aprons are commonly used to protect the patient against unnecessary radiation. However, they are practically of no use to the patient as it has been shown by the present measurements. The scatter radiation produced in the body of the patient creates organ doses outside of the collimated radiation field.

Image quality from high-resolution CT of the lung: comparison of axial scans and of sections reconstructed from volumetric data acquired using MDCT.

Objective: Our objective was to compare the image quality of reconstructed thin sections obtained from a 16-MDCT scanner with that of axial high-resolution CT scans of the same patient.

Subjects And Methods: Fifty consecutive patients referred for CT of the chest underwent 16-MDCT and, subsequently, axial high-resolution CT. The volumetric raw data from the MDCT scans were reconstructed into slices 2-mm thick using a high-spatial-frequency reconstruction algorithm.

[Dose exposure from analog and digital full mouth radiography and panoramic radiography].

The present study investigated the dose exposition in the head and neck region by use of analog and digital radiographic dental systems. Four radiographic devices were tested: panoramic radiography (analog and digital) and 14-image full-mouth-survey (FMS, analog and digital). Organ doses were measured on a Rando-phantom by use of CaF2-dosimeters according to the IRCP-guidelines and the effective doses calculated.

[State of measures of quality assurance for radiotherapy units in Switzerland].

In Switzerland 57 X-ray therapy units are in operation at present. According to the Swiss Ordinance on Radiation Protection, a quality-assurance program must regularly be applied in to these units. However, as the Swiss X-ray Ordinance gives explicit control parameters only for diagnostic units, the present article issues proposals for the realization of a quality-assurance program for the therapy units.