The median effective dose and number of examinations per quarter year in mSv for all examination between January 2010 and December 2012.

<p>With the introduction the IR system (between 1/11 and 2/11) a significant reduction in radiation exposure can be reported.</p

The median effective dose and number of examinations per quarter year in mSv for thorax-abdomen-pelvis CT examinations.

<p>With the introduction the IR system (between 1/11 and 2/11) a significant reduction in radiation exposure can be reported. The clinical value of a DMS is demonstrated with the increase in effective dose in 4/11 and the direct detection and correction. </p

The median effective dose and number of examinations per quarter year in mSv for low dose scans of the cranial (for example sinuses).

<p>Note it is important to point out that for unenhanced neurological CT scan the effect of IR in combination with a wide-detector configuration is naturally minor.</p

Filtered tomographic slices of a metastasis of a low-grade adenocarcinoma in a steatotic liver filtered with the 3D bilateral filter.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively. (F) shows the histogram of the filtered absorption image (top) and the filtered phase-contrast image (bottom) with red dashed lines marking the window level in the shown slices.</p

Filtered tomographic slices of a subcapsular hematoma.

<p>Conventional absorption- based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and the histogram (F) of the absorption (top) and the phase-contrast image (bottom) show the window level as red dashed lines. In the absorption images (A, D) the contrast between the liver tissue in the upper right part of the image (A, D) and the subcapsular hematoma in the lower left part is considerably lower compared to the phase-contrast image (B, E) where the hematoma shows a high signal.</p

Comparison of unfiltered and filtered tomographic slices of a metastasis of a low-grade adenocarcinoma in a steatotic liver.

<p>Axial slices of the conventional absorption-based (A, D) and the phase-contrast (B, E) tomography windowed using the same window level and window width. The histograms of both unfiltered (C) and filtered (F) tomographic datasets demonstrate the filtering result and the red dashed markers show the window level. The areas I (red, surrounding formalin) and II (blue, high-contrast tumor in (B) mark the regions of 30×30 pixels, which were averaged for CNR calculation.</p

Filtered tomographic slices of a liver metastasis of a mucinous adenocarcinoma of the colon.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and (F) shows the histograms of both signals with red dashed lines marking the window level. In the absorption images (A, C) only the mucinous parts of the metastasis are visible as areas with low density. The phase-contrast images (B, E) show a significantly higher soft-tissue contrast with low signal in the mucinous areas, intermediate signal in the liver tissue and higher signal for the tumor tissue and necrotic/hemorrhagic areas.</p

Tomographic slices of a cholangiocellular carcinoma in a liver with macrosteatosis and pilosis filtered with the 3D bilateral filter.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively. (F) shows the histogram of the filtered absorption image (top) and the filtered phase-contrast image (bottom) with red dashed lines marking the window level in the shown slices. The absorption images (A, D) profit strongly from the filtering, but the information is still complementary.</p

Filtered tomographic slices of a hepatocellular carcinoma in a cirrhotic liver.

<p>The patient had received transcatheter arterial chemoembolisation (TACE). Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and (F) shows the histogram of the absorption (top) and the phase-contrast image (bottom) with red dashed lines marking the window level. In the absorption images (A, D) the HCC nodules in the right center (marked with red arrows in A) are visible due to the high density of the retained Lipiodol. In the phase-contrast images (B, D) the fibrous septa are visible as high signal bands whereas the liver tissue and the HCC nodules show intermediate signal. Some areas with increased Lipiodol retention show low signal.</p

Ultra Low Dose CT Pulmonary Angiography with Iterative Reconstruction

<div><p>Objective</p><p>Evaluation of a new iterative reconstruction algorithm (IMR) for detection/rule-out of pulmonary embolism (PE) in ultra-low dose computed tomography pulmonary angiography (CTPA).</p><p>Methods</p><p>Lower dose CT data sets were simulated based on CTPA examinations of 16 patients with pulmonary embolism (PE) with dose levels (DL) of 50%, 25%, 12.5%, 6.3% or 3.1% of the original tube current setting. Original CT data sets and simulated low-dose data sets were reconstructed with three reconstruction algorithms: the standard reconstruction algorithm “filtered back projection” (FBP), the first generation iterative reconstruction algorithm iDose and the next generation iterative reconstruction algorithm “Iterative Model Reconstruction” (IMR). In total, 288 CTPA data sets (16 patients, 6 tube current levels, 3 different algorithms) were evaluated by two blinded radiologists regarding image quality, diagnostic confidence, detectability of PE and contrast-to-noise ratio (CNR).</p><p>Results</p><p>iDose and IMR showed better detectability of PE than FBP. With IMR, sensitivity for detection of PE was 100% down to a dose level of 12.5%. iDose and IMR showed superiority to FBP regarding all characteristics of subjective (diagnostic confidence in detection of PE, image quality, image noise, artefacts) and objective image quality. The minimum DL providing acceptable diagnostic performance was 12.5% (= 0.45 mSv) for IMR, 25% (= 0.89 mSv) for iDose and 100% (= 3.57 mSv) for FBP. CNR was significantly (p < 0.001) improved by IMR compared to FBP and iDose at all dose levels.</p><p>Conclusion</p><p>By using IMR for detection of PE, dose reduction for CTPA of up to 75% is possible while maintaining full diagnostic confidence. This would result in a mean effective dose of approximately 0.9 mSv for CTPA.</p></div