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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. The image quality was evaluated using the signal difference to noise ratio (SDNR) and the spatial resolution of a line-pair insert in the phantom head. The dose efficiency, defined as the ratio of SDNR and effective dose, was also compared. Results The organ and surface doses were lowest with the high-class CT protocol, but the image quality was the worst. Image quality was best with the cone beam CT protocol, which, however, had the highest radiation exposure in this study, whereas the mid-class CT was in between. Conclusion Based on our results, high-end CT should be used for surgical planning because it has the lowest dose, while the image quality is still sufficient for this purpose. However, if highest image quality is needed and required, e.g., by ENT surgeons, the other modalities should be considered.

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. The $\mathbf{SSDE}$ values automatically provided by the scanner were compared with ${\mathbf{SSDE}}_{\mathbf{BMI}}$ determined from $\mathbf{C}{\mathbf{TDI}}_{\mathbf{vol}}$ and $\mathbf{BMI}$. A good accordance of ${\mathbf{SSDE}}_{\mathbf{BMI}}$ and $\mathbf{SSDE}$ was found for the chest and abdominal regions. A low correlation was observed for the head region. The presented method is a simple and practically useful surrogate approach for the chest and abdominal regions but not for the head.

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. If possible, alternatives should be used, or examinations postponed to a time after the pregnancy. This review gives a summary of the procedure for determining the radiation exposure of a pregnant woman. Based on the previous report of 2002 and the literature on prenatal radiation exposure published thereafter, the DGMP/DRG report on the procedure for the assessment of prenatal radiation exposure was adapted to the current state of science and technology. Typically, only relatively low radiation exposures of less than 20 mSv occur for the unborn child in X-ray diagnostics in the vast majority of cases. At these dose level the additional risk of damage to the embryo or fetus caused by the radiation is low and therefore only a rough conservative estimate using tabulated values are made. Only in a few types of examination (CT and interventional radiology) higher doses values might occur in the uterus. Instead of dose estimates (step 1 in the two-step model) in these cases the calculation of dose (step 2) are required and further action by the physician may be necessary. During the assessment, it is useful to initially use simple conservative estimation procedures to quickly determine whether a case falls into this large group less than 20 mSv, where there is a very low risk to the unborn child. If this is the case, the pregnant woman should be informed immediately by the doctor who performed the examination/treatment. This avoids a psychological burden on the patient. The DGMP/DRG report suggests a relatively simple, clearly structured procedure with advantages for all parties involved (physician, medical physics experts, MTRA and patient). · The DGMP/DRG report on prenatal radiation exposure describes the procedure for calculating radiation exposures and the associated risks for the unborn child.. · Using the two-step model, only a simple assessment based on the first step is necessary for most prenatal radiation exposures.. · With the given tables it is possible to estimate individual risks for the unborn child taking into account the radiation exposure.. · Only in the rare case that the first estimate results in a uterine dose larger 20 mSv a more accurate calculation is necessary..· Fiebich M, Block A, Borowski M et al. Prenatal radiation exposure in diagnostic and interventional radiology. Fortschr Röntgenstr 2021; 193: 778 - 786. Die Exposition einer Schwangeren mit Röntgenstrahlung ist ein Ereignis, das bei allen Beteiligten Unsicherheit hervorrufen kann. Diese Übersichtsarbeit gibt Hinweise, wie eine derartige Situation zu bewerten ist und wie die Dosis für das ungeborene Kind ermittelt werden kann. Generell gilt, dass die Anwendung von Röntgenstrahlung bei Schwangeren in der Radiologie möglichst vermieden, Alternativen genutzt oder die Anwendung auf einen Zeitpunkt nach der Schwangerschaft verschoben werden sollen. Diese Übersichtsarbeit gibt eine Zusammenfassung der Vorgehensweise zur Bestimmung der Strahlenexposition einer Schwangeren. Auf Basis des Vorgängerberichts von 2002 und der danach publizierten Literatur zur pränatalen Strahlenexposition wurde der DGMP/DRG-Bericht zur Vorgehensweise bei der Bewertung der pränatalen Strahlenexposition dem Stand von Wissenschaft und Technik angepasst. Typischerweise treten in der Röntgendiagnostik in den überwiegend meisten Fällen nur relativ geringe Strahlenexpositionen kleiner als 20 mSv für das Ungeborene auf. Bei diesen Dosen ist das durch die Strahlung erzeugte zusätzliche Risiko für eine Schädigung des Embryos bzw. des Fötus gering und daher erfolgt hier nur eine grobe konservative Abschätzung nach Tabellenwerten. Nur bei wenigen Untersuchungsarten (CT oder interventionelle Radiologie) können höhere Werte der Uterusdosis erreicht werden. Statt der Dosisabschätzungen (Stufe 1 im 2-Stufen-Modell) sind in diesen Fällen Berechnungen (Stufe 2) zur Bestimmung der Dosis erforderlich und ggf. auch weitergehende Handlungen der Ärztin/des Arztes notwendig. Es ist sinnvoll, bei der Bewertung zunächst mit einfachen konservativen Abschätzverfahren schnell festzustellen, ob ein Fall in diese große Gruppe kleiner als 20 mSv fällt, bei der eine sehr geringe Gefährdung des Embryos oder Fötus vorliegt. Ist dies der Fall, so soll die Schwangere von der Ärztin/dem Arzt, die/der die Untersuchung/Behandlung durchgeführt hat, sogleich davon unterrichtet werden. Dies vermeidet eine psychologische Belastung der Patientin. Der DGMP/DRG-Bericht schlägt ein relativ einfaches, klar strukturiertes Vorgehen vor, mit entsprechenden Vorteilen für alle Beteiligten (Arzt, Medizinphysik-Experten, MTRA und Patient). · Der DGMP/DRG-Bericht zur pränatalen Strahlenexposition beschreibt die Vorgehensweise bei der Berechnung der Strahlenexpositionen und der damit verbundenen Risiken für das Ungeborene.. · Dem 2-Stufen-Modell folgend ist für die meisten pränatalen Strahlenexpositionen nur eine einfache Abschätzung nach der ersten Stufe notwendig.. · Anhand von Tabellenwerten ist eine Abschätzung einzelner Risiken für das Ungeborene unter Berücksichtigung der Strahlenexposition möglich.. · Nur im seltenen Fall, dass die erste Abschätzung eine Uterusdosis größer als 20 mSv ergibt, ist eine genauere Berechnung notwendig..· Fiebich M, Block A, Borowski M et al. Prenatal radiation exposure in diagnostic and interventional radiology. Fortschr Röntgenstr 2021; 193: 778 – 786.

Objective: The degeneration of articular cartilage is part of the clinical syndrome of osteoarthritis (OA) and one of the most common causes of pain and disability in middle-aged and older people(1). However, the objective detection of an initial state of OA is still challenging. In order to categorize cartilage into states of OA, an algorithm is presented which offers objective categorization on the basis of two-photon laser-scanning microscopy (TPLSM) images. Methods: The algorithm is based on morphological characteristics of the images and results in a topographical visualization. This paper describes the algorithm and shows the result of a categorization of human cartilage samples. Results: The resulting map of the analysis of TPLSM images can be divided into areas which correspond to the grades of the Outerbridge-Categorization. The algorithm is able to differentiate the samples in coincidence with the macroscopic impression. Conclusion: The method is promising for early OA detection and categorization. In order to achieve a higher benefit for the physician the method must be transferred to an endoscopic setup for an application in surgery. (C) 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand.Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose.The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT.Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization.• Low dose examinations of the hand are feasible in CBCT and MDCT.• In default settings CBCT has a lower dose than MDCT.• MDCT enables a good image quality at a lower dose than CBCT. Citation Format: • Neubauer J, Neubauer C, Gerstmair A et al. Comparison of the Radiation Dose from Cone Beam Computed Tomography and Multidetector Computed Tomography in Examinations of the Hand. Fortschr Röntgenstr 2016; 188: 488 - 493.

Purpose: In 2 institutions exposure values were evaluated and compared with the 2010 updated diagnostic reference levels (DRL) and possibilities for decreasing the dose assessed. Materials and Methods: Mean exposure values obtained during a 3-month period were calculated for all modalities (X-ray: imaging plate system and digital detector; dual-source 64- and 16- slice spiral CT) as well as examination types were compared to old diagnostic reference levels in addition to DRLs introduced in 2010. Then 10 examinations of all modalities and types were accompanied by a medical physicist and optimized stepwise if necessary. Results: The mean values of X-ray examinations were above DRL. All accompanied examinations were beyond DRL except lateral lumbar spine (LSP) and lateral thoracic X-ray, which were elevated due to statistical outliers from morbidly obese patients or patients with metallic implants. For a-p LSP tube voltage was increased. While image quality was maintained, dose area product (DAP) was reduced by 50 % to123 ± 61 cGy · cm² for LSP a-p and 30 % for lateral LSP to 229 ± 116 cGy · cm². For CT examinations, dose was below DRL. Accompanied examinations of the lumbar spine performed on a 16-slice spiral CT demonstrated a result 68 % above DRL with dose length product (DLP) of 840 ± 252 cGy · cm. For optimization, pitch and tube voltage were stepwise increased and DLP reduced below DRL. Conclusion: Systematic analysis of our internal exposure values on the occasion of adaptation of DRL is crucial for prompt detection of exceeded values independently from assessment by the responsible authority and initiation of proper measures for decreasing exposure dose. Hereby active dose management is attained. Key Points: • Analysis of exposure values for high data volumes obtained from the Radiology Information System (RIS) is possible independent of weight. • Summation of small groups of patients with different weights might result in high exposure values (DRL 70 kg). • If high exposure values are observed in small groups of patients, individual analysis of examinations is mandatory. • Active dose management can be obtained by an analysis of average exposure of all examinations obtained during a specific observation period. • Potential for optimization of exposure values might be possible even they fall below DRL. Citation Format: • Schafer S, Alejandre-Lafont E, Schmidt T et al. Dose Management for X-Ray and CT: Systematic Comparison of Exposition Values from two Institutes to Diagnostic Reference Levels and Use of Results for Optimisation of Exposition. Fortschr Rontgenstr 2014; 186: 785 – 794

Purpose Evaluation of 15,000 computed tomography (CT) examinations to investigate if iterative reconstruction (IR) reduces sustainably radiation exposure. Method and Materials Information from 15,000 CT examinations was collected, including all aspects of the exams such as scan parameter, patient information, and reconstruction instructions. The examinations were acquired between January 2010 and December 2012, while after 15 months a first generation IR algorithm was installed. To collect the necessary information from PACS, RIS, MPPS and structured reports a Dose Monitoring System was developed. To harvest all possible information an optical character recognition system was integrated, for example to collect information from the screenshot CT-dose report. The tool transfers all data to a database for further processing such as the calculation of effective dose and organ doses. To evaluate if IR provides a sustainable dose reduction, the effective dose values were statistically analyzed with respect to protocol type, diagnostic indication, and patient population. Results IR has the potential to reduce radiation dose significantly. Before clinical introduction of IR the average effective dose was 10.1±7.8mSv and with IR 8.9±7.1mSv (p*=0.01). Especially in CTA, with the possibility to use kV reduction protocols, such as in aortic CTAs (before IR: average14.2±7.8mSv; median11.4mSv /with IR:average9.9±7.4mSv; median7.4mSv), or pulmonary CTAs (before IR: average9.7±6.2mSV; median7.7mSv /with IR: average6.4±4.7mSv; median4.8mSv) the dose reduction effect is significant(p*=0.01). On the contrary for unenhanced low-dose scans of the cranial (for example sinuses) the reduction is not significant (before IR:average6.6±5.8mSv; median3.9mSv/with IR:average6.0±3.1mSV; median3.2mSv). Conclusion The dose aspect remains a priority in CT research. Iterative reconstruction algorithms reduce sustainably and significantly radiation dose in the clinical routine. Our results illustrate that not only in studies with a limited number of patients but also in the clinical routine, IRs provide long-term dose saving.

Rationale and Objectives. This article presents an evaluation of an automated technique for determining the colon centerline with computed tomographic (CT) data sets. Materials and Methods. The technique proceeds as follows. After indication of a voxel in the rectum, voxels corresponding to air were segmented. Points along the colon centerline were estimated on the basis of centers of mass of grown voxels. A second segmentation and centerline calculation was initiated at the cecum. These two centerlines were then averaged. The resulting average was refined by using lumen data obtained perpendicular to the average centerline. The accuracy of the technique was investigated with simulation phantoms. The technique was also evaluated for 40 clinical colon cases. Calculated centerline points were compared with those indicated by radiologists for a randomly selected clinical case. Results. In the simulation studies, the calculated centerline points were, on average, within 2.5 mm of the true centerlines but differed by up to 4 mm in regions of deep folds or sharp turns. In the clinical colon study, 40% of the centerlines were computed with a single seed point and 25% with two seed points. Average centerlines were computed in 1 minute. The root mean square difference between the computed centerline points and those indicated by the radiologists was 4–5 mm (comparable to interobserver variations). Conclusion. Accurate centerlines can be determined from colon CT data with this automated technique.

A confocal imaging and image processing scheme is introduced to visualize and evaluate the spatial distribution of spectral information in tissue. The image data are recorded using a confocal laser-scanning microscope equipped with a detection unit that provides high spectral resolution. The processing scheme is based on spectral data, is less error-prone than intensity-based visualization and evaluation methods, and provides quantitative information on the composition of the sample. The method is tested and validated in the context of the development of dermal drug delivery systems, introducing a quantitative uptake indicator to compare the performances of different delivery systems is introduced. A drug penetration study was performed in vitro. The results show that the method is able to detect, visualize and measure spectral information in tissue. In the penetration study, uptake efficiencies of different experiment setups could be discriminated and quantitatively described. The developed uptake indicator is a step towards a quantitative assessment and, in a more general view apart from pharmaceutical research, provides valuable information on tissue composition. It can potentially be used for clinical in vitro and in vivo applications.