Martin Hupfer

Learn More
PURPOSE At present, no established methods exist for dosimetry in micro computed tomography (micro-CT). The purpose of this study was therefore to investigate practical concepts for both dosimetric scanner quality assurance and tissue dose assessment for micro-CT. METHODS The computed tomography dose index (CTDI) was adapted to micro-CT and measurements(More)
PURPOSE To determine the dose-length product (DLP)-effective dose (ED) (DLP/ED) conversion coefficient (k) tables for the lower extremities that can be used for calculating ED. MATERIALS AND METHODS Dose calculations were performed on standard phantoms using a validated Monte Carlo calculation tool. Calculations were performed to obtain ED values for tube(More)
PURPOSE To investigate the dose saving potential of direct-converting CdTe photon-counting detector technology for dedicated breast CT. MATERIALS AND METHODS We analyzed the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) of two detector technologies, suitable for breast CT (BCT): a flat-panel(More)
PURPOSE Currently, only iodine- and barium-based contrast media (CM) are used in clinical contrast-enhanced computed tomography (CE-CT). High-Z metals would produce a higher contrast at equal mass density for the x-ray spectra used in clinical CT. Using such materials might allow for significant dose reductions in CE-CT. The purpose of this study was to(More)
OBJECTIVES Dynamic contrast-enhanced imaging allows assessing functional information in addition to morphology using various modalities. Several applications have been established in clinical practice; however, there is no standard with respect to injection protocols or postprocessing algorithms. The purpose of this study was to develop a phantom for(More)
To evaluate the potential of in vivo dynamic contrast-enhanced micro-computed tomography (DCE micro-CT) for the assessment of antiangiogenic drug therapy response of mice with mammary carcinoma. 20 female mice with implanted MCF7 tumours were split into control group and therapy group treated with a known effective antiangiogenic drug. All mice underwent(More)
The purpose of this study was to investigate the effect of shaped filters specifically designed for dedicated breast computed tomography (CT) scanners on dose and image quality. Optimization of filter shape and material in fan direction was performed using two different design methods, one aiming at homogeneous noise distributions in the CT images and the(More)
OBJECTIVES Spectral optimization of x-ray computed tomography (CT) has led to substantial radiation dose reduction in contrast-enhanced CT studies using standard iodinated contrast media. The purpose of this study was to analyze the potential for further dose reduction using high-atomic-number elements such as hafnium and tungsten. As in previous studies,(More)
One of the biggest challenges in dynamic contrast-enhanced CT is the optimal synchronization of scan start and duration with contrast medium administration in order to optimize image contrast and to reduce the amount of contrast medium. We present a new optically based approach, which was developed to investigate and optimize bolus timing and shape. The(More)
PURPOSE Modern computed tomography (CT) systems are supporting increasingly fast rotation speeds, which are a prerequisite for fast dynamic acquisition, e.g. in perfusion imaging, and for new modalities such as dedicated breast CT, where breathhold scanning is indicated. However, not all detector technologies are supporting the high frame rates that are(More)