Impact of Allura Clarity technology on radiation dose exposure during left atrial appendage closure

Background: To evaluate the impact of the Clarity IQ technology on reducing radiation risk in patients undergoing cardiac interventional radiology (IR) procedures. Material/Methods: Phantom studies were performed with two angiographic systems, FD10 Allura Xper and FD10 Allura Clarity. In the study, we performed left atrial appendage closure. Dosimetric measurements were performed with thermoluminescent dosimeters (TLD) placed inside a CIRS anthropomorphic phantom. Radiation risk was estimated based on the TLD readings and expressed as the dose absorbed by particular organs. The Mann-Whitney U test was carried out to test for significance of differences in the absorbed radiation doses between the techniques. Results: During left atrial appendage closure, the estimated dose absorbed by particular organs was lower in the case of the FD10 Allura Clarity system in comparison to the Allura Xper. In this procedure, dose reduction for particular organs ranged between 49-86%. Conclusions: Application of the FD10 Allura Clarity system resulted in a significant dose reduction, thereby leading to a significant decrease in radiation risk for patients undergoing IR procedures

Dose and noise in abdominal computed tomography examinations

Background: Dose reduction in computed tomography (CT) examinations was an idea of the Co-rdinated Research Project (CRP) "Dose Reduction in Computed Tomography (CT) while maintaining Diagnostic Confidence", supported by the International Agency of Atomic Energy (IAEA) in the years 2003-2005. Participation in the CRP inspired the authors' attempts to elaborate a method for optimization of CT abdominal procedures allowing reduce a dose to patient with saving diagnostically satisfying image quality. The paper presents the algorithm together with clinical verification of the results of the study. Material/Methods: Two types of single-slice CT scanners were used for the investigations. The images recorded for patients undergoing routine abdomen examinations and then these obtained with modified exposure parameters were analyzed. The influence of the changed tube outputs on image quality was checked using Catphan 424 phantom. Results: As the result no statistically significant difference between the measured noise in clinical images for patients examined at routine and modified settings (within the same weight category) was observed. Conclusions: The conclusion was that at routine (screening) abdomen examinations, the dose may be reduced up to 50% with saving diagnostically satisfying image quality

Stat3 is required to maintain the full differentiation potential of mammary stem cells and the proliferative potential of mammary luminal progenitors.

Stat3 has a defined role in mammary gland where it is a critical mediator of cell death during post-lactational regression. On the other hand, Stat3 is required for the self-renewal of embryonic stem cells and is sufficient for the induction of a naïve pluripotent state in epiblast stem cells. Mammary stem cells (MaSCs) have a high capacity for self-renewal and can grow robustly in transplantation experiments in vivo. However, a role for Stat3 in MaSCs has not been investigated. Here we show that depletion of Stat3 from basal cells results in reduced primary transplantation efficiency and diminishes the potential to generate ductal, but not alveolar, outgrowths. In addition, Stat3 is required for maximal proliferation of luminal progenitors

Zagrożenia zdrowotne wśród dzieci i młodzieży. T. 3

Praca recenzowana / Peer-reviewed pape

MSCT and C-arm units : doses to patients in the chest angiography procedures

Background: Since the late 1990's, computed tomography (CT) technique has become an alternative solution to "traditional" angiographies. Angio-CT (CTA) is most frequently used in cardiovascular procedures. Evaluation of patient doses in both CTA and "traditional" cardio-angiography was the aim of the presented study. Material/Methods: The measurements were performed using three multislice CT scanners (MSCT) for exposures covering the chest area and three C-arm units for conventional coronary angiographies. The patient was represented by a Rando Man phantom and organ doses were evaluated on the basis of readings from thermoluminscent dosimeters. Results: Doses absorbed during CT angiography (CTA) were evaluated for eight exposures at "chest-angio" protocols and two exposures at "coronary" protocols. Doses absorbed during conventional coronary angiography were also evaluated for eight exposures on the three C-arm units. Conclusions: 1. In coronary angiography carried out by C-arm units patient organ doses are distributed nonuniformly inside patient body (from up to 100 mGy in area of primary x-ray beam to about zero in quite near vicinity). Therefore, a low effective dose does not mean the low absorbed doses at all. 2. Doses to patients in CTA procedures covered the chest are distributed more uniformly and are dependent on exposure pattern (i.e. configuration of projections). 3. The lowest doses in CTA covered the chest are higher then those measured at conventional cardio-angiography

Phantom studies as useful method for optimization of CT procedures with single-slice scanners

Background: Optimization of X-ray diagnostic procedures requires a selection of exposure parameters adequately for the patient anatomical structure and clinical needs, meanwhile use of the ready software protocols is a daily routine. The paper presents the methods and the results based on phantom studies aimed to optimize the exposure parameters for the examined object in examinations performed using single-slice CT scanners. Material/Methods: The studies were concerned with the significance of particular exposure parameters for image quality and patient doses in routine head procedures. Image quality was evaluated using a Catphan 424 phantom. Dosimetric measures of exposure were evaluated by computed tomography dose index (CTDI), and dose-length-product (DLP) was measured using a Nomex dosimeter. Results/Conclusions: Two single-slice CT scanners were investigated in details: a fourth generation one (Picker PQ-2000) and a third generation one (Siemens Somatom Balance). The dependence of image quality factors on high voltage, anode current, scan time, slice thickness were described and CTDI was evaluated. For both the CT scanners tested, the combinations of exposure parameters were found for which low dose value was accompanied by good image quality. Moreover, the high-contrast resolution was not practically changed with dose reduction, in opposite to low-contrast resolution being related to exposure parameters and the type of CT scanner. Dose reduction possible for the fourth generation scanner is deeper