A nonparametric measure of contrast in x-ray images.

We propose a nonparametric figure of merit, the contrast equivalent distance CED, to measure contrast directly from clinical images.A relative brightness distanceis calculated by making use of the order statistic of the pixel values. By multiplyingwith the grey value range, the mean brightness distance MBD is obtained.

PAE planning: Radiation exposure and image quality of CT and CBCT.

Purpose: To determine accurate organ doses, effective doses, and image quality of computed tomography (CT) compared with cone beam CT (CBCT) for correct identification of prostatic arteries.

Method: A dual-energy CT scanner and a flat-panel angiography system were used. Dose measurements (gallbladder (g), intestine (i), bladder (b), prostate (p), testes (t), active bone marrow of pelvis (bmp) and femura (bmf)) were performed using an anthropomorphic phantom with 65 thermoluminescent dosimeters in the pelvis and abdomen region.

Radiology meets archaeology: digital restoration and 3D printing using CT data.

Aim: Archaeological objects are often recovered in blocks since highly porous materials and unstable and highly decayed objects cannot always be uncovered undamaged or time and resources for classic uncovering are lacking. Therefore, clinical computed tomography (CT) combined with freely available software solutions should be tested as a simple and fast method for visualizing and analyzing archaeological finds as an alternative to time-consuming restoration.

Materials And Methods: As an example, a block with a shield boss was selected from a block excavation and examined by means of CT.

Comparison of the radiation protection effect of different radiation protection aprons made of different materials.

Objective: The objective of this study is to examine the performance of new generation protection aprons as alternative to conventional lead aprons regarding their radiation protection effectiveness.

Method And Materials: Radiation protection aprons made of lead-containing and lead-free materials from a total of seven companies were compared. Furthermore, different lead equivalent values of 0.

[Use of patient radiation shielding in diagnostic and interventional radiology].

The use of patient contact shielding provides an opportunity to reduce patient radiation exposure. Recently, the use has been the subject of controversy. The Radiation Protection Committee has published a recommendation on the use of patient radiation shields by considering the recent findings on dose savings but also the risks of incorrect use.

In vitro measurements of radiation exposure with different modalities (computed tomography, cone beam computed tomography) for imaging the petrous bone with a pediatric anthropomorphic phantom.

Background: Various imaging modalities, such as multi-detector computed tomography (CT) and cone beam CT are commonly used in infants for the diagnosis of hearing loss and surgical planning of implantation hearing aid devices, with differing results.

Objective: We compared three different imaging modalities available in our institution, including a high-class CT scanner, a mid-class CT scanner and an angiography system with a cone beam CT option, for image quality and radiation exposure in a phantom study.

Materials And Methods: While scanning an anthropomorphic phantom imitating a 1-year-old child with vendor-provided routine protocols, organ doses, surface doses and effective doses were determined for these three modalities with thermoluminescent dosimeters.

CAN THE SIZE-SPECIFIC DOSE ESTIMATE BE DERIVED FROM THE BODY MASS INDEX? A FEASIBILITY STUDY.

Size-specific dose estimate ($\mathbf{SSDE}$) index appears to be more suitable than the commonly used volume computed tomography dose index ($\mathbf{C}{\mathbf{TDI}}_{\mathbf{vol}}$) to estimate the dose delivered to the patient during a computed tomography (CT) scan. We evaluated whether an ${\mathbf{SSDE}}_{\mathbf{BMI}}$ can be determined from the patient's body mass index ($\mathbf{BMI}$) with sufficient reliability in the case that a $\mathbf{SSDE}$ is not given by the CT scanner. For each of the three most used examination types, CT examinations of 50 female and 50 male patients were analyzed.

Joint replacement increases radiation exposure to the staff in angiography: A phantom study.

Introduction: The present study investigates the influence of joint prostheses on the amount of scattered radiation in a simulated angiography set-up.

Materials And Methods: A clinical angiography system (Artis Zee, Siemens Healthineers, Germany) with a water phantom as a scattering object was used. The scattered radiation of the water phantom was repeatedly measured without prosthesis, with a knee prosthesis and a hip prosthesis made from titanium, aluminum, vanadium, ceramics and polyethylene.

[Prenatal Radiation Exposure in Nuclear Medicine].

Radiation exposure from nuclear medicine procedures during pregnancy may cause uncertainty among patients and medical professionals. In 2019, the German Society of Medical Physics (DGMP) and the German Society of Radiology (DRG) published a fully revised version of the report "Prenatal Radiation Exposure Arising from Medical Indication, Dose Calculation, Conclusions for Physicians and Pregnant Women". This report offers a basis for dose calculation and determination of radiation exposure to the unborn.

Prenatal radiation exposure in diagnostic and interventional radiology.

Background:  The exposure of a pregnant woman to X-rays is an event that can cause uncertainty for all concerned. This review provides guidance on how to assess such a situation and how to determine the dose to the unborn child. In general, the use of X-rays in pregnant women in radiology should be avoided.

Scatter radiation reduction with a radiation-absorbing pad in interventional radiology examinations.

Purpose: Radiation-absorbing pads are an additional possibility to reduce scattered radiation at its source. The goal of this study is to investigate the efficacy of a new reusable radiation-absorbing pad at its origin in an experimental setup.

Material And Methods: All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol, different C-arm angulations and an anthropomorphic torso phantom as a scattering body.

Watershed phenomena during extracorporeal life support and their clinical impact: a systematic in vitro investigation.

Aims: Extracorporeal life support (ECLS) during acute cardiac failure restores haemodynamic stability and provides life-saving cardiopulmonary support. Unfortunately, all common cannulation strategies and remaining pulmonary blood flow increase left-ventricular afterload and may favour pulmonary congestion. The resulting disturbed pulmonary gas exchange and a residual left-ventricular action can contribute to an inhomogeneous distribution of oxygenated blood into end organs.

Modification of chest radiography exposure parameters using a neonatal chest phantom.

Background: The acquisition of chest radiographs in neonates is of critical importance in diagnostics because of the risk of respiratory distress syndrome and pneumothorax in preterm infants.

Objective: To achieve a dose reduction while preserving a diagnostic image quality for chest radiographs of neonates.

Materials And Methods: All radiographs, generated on a fully digital X-ray unit by using a neonatal chest phantom, were evaluated under variation of the tube voltage (40-70 kV) and mAs levels (1-10.

Protective Efficacy of Different Ocular Radiation Protection Devices: A Phantom Study.

Purpose: The aim of this study was to investigate the efficacy of different designs and types of ocular radiation protection devices depending on simulated varied body heights in a phantom-simulated thoracic intervention.

Materials And Methods: A clinical angiography system with a standardized fluoroscopy protocol with an anthropomorphic chest phantom as a scattering object and optically stimulated luminescence dosimeters for measuring radiation dose were used. The dosimeters were placed at the position of eyes of an anthropomorphic head phantom simulating the examiner.

Breast phantoms for 2D digital mammography with realistic anatomical structures and attenuation characteristics based on clinical images using 3D printing.

The aim of this work was to develop a production process for breast phantoms for 2D digital mammography (DM) with realistic anatomical structures and attenuation characteristics based on clinical images using 3D printing. The presented production process is based on PolyJet 3D printing technology using a polypropylene like printing material. First, an attenuation calibration function for this material and the achievable lateral resolution of the printing process of about 200 µm was determined.

[Evaluation of intratherapeutic 177Lu-HA-DOTATATE treatment in neuroendocrine tumors: dosimetry with SPECT, whole-body imaging and gamma probe].

Aim:  Peptide receptor radionuclide therapy (PRRT) with Lu-HA-DOTATATE has evolved as a new path in the treatment of somatostatin-receptor-expressing neuroendocrine tumors. The kidneys are proven as organs at risk and should be evaluated dosimetrically. Overlap with other organs will make dosimetry based on planar scintigraphy inaccurate.

Development and Validation of a Life-Sized Mock Circulatory Loop of the Human Circulation for Fluid-Mechanical Studies.

Mock circulatory loops (MCLs) are usually developed for assessment of ventricular assist devices and consist of abstracted anatomical structures represented by connecting tubing pipes and controllable actuators which could mimic oscillating flow processes. However, with increasing use of short-term peripheral mechanical support (extracorporeal life support [ECLS]) and the upcoming evidence of even counteracting flow processes between the failing native circulation and ECLS, MCLs incorporating the peripheral vascular system and preserved anatomical structures are becoming more important for systematic assessment of these processes. For reproducible and standardized fluid-mechanical studies using magnetic resonance imaging, Doppler ultrasound, and computational fluid dynamics measurements, we developed a MCL of the human circulation.

Effectiveness of a new radiation protection system in the interventional radiology setting.

Objectives: The goal of this study was to examine a new weightless-like radiation protection garment regarding its radiation protection efficacy and to compare it to a conventional two-piece apron suit plus thyroid collar and standard ancillary shields.

Material And Methods: All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol for different C-arm angulations. An anthropomorphic torso phantom served as a scattering body.

[Digital volume tomography : Dedicated scanner and cone beam CT with C‑arm systems].

Clinical/methodical Issue: Digital volume tomography (DVT) and cone-beam computed tomography (CT) with C‑arm systems have become established three-dimensional imaging systems as an alternative to CT in some application areas.

Standard Radiological Methods: The technology of the systems is well developed so that they have become a competing method to CT imaging in terms of image quality and radiation exposure.

Performance: An advantage is the better spatial resolution, preferably with dedicated scanner systems, especially in the z direction.

[Practical radiation protection of the patient in radiological diagnostics].

Background: The use of radiation protection equipment can reduce the radiation exposure of patients.

Objectives: The aim was to show which patient shields should be used for the different types of examination.

Methods: The results of multiple studies were compiled and analyzed and recommendations made for the use of patient shields.

Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists.

Purpose: To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures.

Methods: As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting.

Optimizing radiation exposure for CT localizer radiographs.

Introduction: The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer.