Abstract：
:The quantification of myocardial perfusion with contrast agent (CA) tracers requires the precise knowledge of the arterial input function (AIF). In this study a method for MR-guided vascular interventions is evaluated that determines the AIF via an active tracking catheter during targeted CA injection. A phantom experiment with a dialysis filter was conducted to measure the AIF using an active catheter and a dynamic image series as reference. To compensate for dilution and coil sensitivity effects, correction methods were developed for the catheter-based AIF determination. From the dynamic MR measurements in the perfusion phantom quantitative perfusion maps were calculated by a deconvolution of the measured CA concentration with the AIF, and additional flow measurements were used to normalize the perfusion map. The signal-time-curves of the measured AIF using the catheter-based and imaging-based methods agree while the absolute values differ by a scaling factor of about 9. After normalization to the surrounding flow, both perfusion techniques are in excellent agreement. Catheter-based AIF measurements are feasible but require an additional normalization which can be determined from a flow measurement. The technique might enable faster perfusion measurements during cardiovascular interventions.
journal_name
Z Med Physjournal_title
Zeitschrift fur medizinische Physikauthors
Stephan S,Reiss S,Lottner T,Özen AC,Bock Mdoi
10.1016/j.zemedi.2020.07.004subject
Has Abstractpub_date
2020-08-29 00:00:00eissn
0939-3889issn
1876-4436pii
S0939-3889(20)30090-8pub_type
杂志文章abstract：PURPOSE:Proton radiography and tomography was investigated since the early 1970s because of its low radiation dose, high density resolution and ability to image directly proton stopping power. However, spatial resolution is still a limiting factor and as a consequence experimental methods and image reconstruction shoul...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2011.06.001
更新日期：2012-06-01 00:00:00
abstract：:As the average corneal shape can effectively be approximated by a conic section, a determination of the corneal shape by biconic parameters is desired. The purpose of the paper is to introduce a straightforward mathematical approach for extracting clinically relevant parameters of corneal surface, such as radii of cur...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2014.02.005
更新日期：2015-03-01 00:00:00
abstract：:Targeted radionuclide therapy (TRT) is an increasingly used treatment modality for a range of cancers. To date, few treatments have involved the use of dosimetry either to plan treatment or to retrospectively ascertain the absorbed dose delivered during treatment. Also the correlation between absorbed dose and biologi...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章,评审
doi：10.1078/0939-3889-00291
更新日期：2006-01-01 00:00:00
abstract：PURPOSE:Multiplication of FLAIR and T2-weighted MRI scans results in images (called FLAIR2) with an improved contrast-to-noise ratio (CNR) for multiple sclerosis (MS) lesions but with a reduced signal-to-noise ratio (SNR). Denoising of these images may therefore further improve FLAIR2 image quality. The purpose of this...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2017.11.001
更新日期：2018-12-01 00:00:00
abstract：:This paper presents a review of the development of optical coherence tomography (OCT), its principles and important applications. Basic OCT systems are described and the physical foundations of OCT signal properties and signal recording systems are reviewed. Recent examples of OCT applications in ophthalmology, cardio...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章,评审
doi：10.1016/j.zemedi.2009.11.002
更新日期：2010-01-01 00:00:00
abstract：:The present study evaluated a hull-volume definition strategy for the planning organ at risk volume (PRV) for the rectum in the planning of radiotherapy of prostate cancer. The bounding volumes of rectum contours of 1 to 5 CT scans were compared on the basis of the rectum coverage probabilities for 5 patients. In addi...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00316
更新日期：2006-01-01 00:00:00
abstract：PURPOSE:To establish a fully automated kV-MV CBCT imaging method on a clinical linear accelerator that allows image acquisition of thoracic targets for patient positioning within one breath-hold (∼15s) under realistic clinical conditions. METHODS AND MATERIALS:Our previously developed FPGA-based hardware unit which al...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2018.01.002
更新日期：2018-04-01 00:00:00
abstract：:The visual evoked potential (VEP) can be used to objectively estimate sensory thresholds. Recently, we developed an adaptive procedure for this threshold estimation based on a Fourier analysis of steady-state responses during the recording. In this study we quantified the reduction in recording time of this adaptive p...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2006.11.006
更新日期：2007-01-01 00:00:00
abstract：:Quantitative Susceptibility Mapping (QSM) is a novel MRI based technique that relies on estimates of the magnetic field distribution in the tissue under examination. Several sophisticated data processing steps are required to extract the magnetic field distribution from raw MRI phase measurements. The objective of thi...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章,评审
doi：10.1016/j.zemedi.2015.10.002
更新日期：2016-03-01 00:00:00
abstract：:The target group of the German mammography screening program, conducted according to the European guidelines, is clearly defined: all women aged 50 to 69 years without evidence of breast cancer are invited to screening mammography every two years. In the present study the question was raised whether breast cancer scre...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2007.12.004
更新日期：2008-01-01 00:00:00
abstract：:The potential benefit of the simultaneous integrated boost (SIB) concept in proton therapy was investigated in a planning study. The proposed fractionation strategy consisted of a SIB treatment following a first phase of conventional fractionation to the elective volume (named SEQ/SIB). The novel method was compared t...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00218
更新日期：2004-01-01 00:00:00
abstract：PURPOSE:To approximate dose-volume histogram (DVH) based quality indicators in volumetric modulated arc therapy (VMAT) planning using multi-criteria optimization (MCO) with a low number of composite optimization parameters. METHODS:The solution space for VMAT optimization with a low number of composite optimization pa...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2020.05.002
更新日期：2020-11-01 00:00:00
abstract：:Today, DICOM is one of the most successful standards in medicine. The standard was developed based on the increasing need for the transfer of digital images between systems of different vendors. Furthermore these images needed to be archived in a system independent format. DICOM has been continuously evolving since th...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/s0939-3889(15)70464-2
更新日期：2002-01-01 00:00:00
abstract：:The present study focused on the reconstruction of the bremsstrahlung spectrum of a clinical linear accelerator from the measured transmission curve, with the aim of improving the accuracy of this method. The essence of the method was the analytic inverse Laplace transform of a parameter function fitted to the measure...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00131
更新日期：2003-01-01 00:00:00
abstract：:Clearance monitor systems are used for gross gamma measurements of waste potentially contaminated with radioactivity. These measurements are to make sure that legal requirements, e.g. clearance criteria according to the german radiation protection ordinance, are met. This means that measurement results may overestimat...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2014.01.001
更新日期：2014-09-01 00:00:00
abstract：:It is known that ionizing radiation is used in medicine for Roentgen diagnostics and for radiation therapy. The radiation interacts with matter, in particular with biological one, essentially by scattering, photoelectric effect, Compton effect and pair production. To what extent the biological material is changed ther...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2008.10.009
更新日期：2009-01-01 00:00:00
abstract：PURPOSE:Respiratory motion is a non-negligible source of uncertainty in radiotherapy. A common approach is to delineate the target volume in all respiratory phases (ITV) and to calculate a treatment plan using the average reconstruction of the four-dimensional computed tomography (4DCT) scans. In this study the extent ...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2015.06.010
更新日期：2016-03-01 00:00:00
abstract：UNLABELLED:Due to the creation of intense local magnetic fields, iron oxide nanoparticles are used as a contrast agent to produce signal loss in Magnetic Resonance Imaging (MRI) in regions where labelled cells have migrated. OBJECTIVE:To study effects of the intracellular distribution of magnetic moments on the extrac...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00323
更新日期：2006-01-01 00:00:00
abstract：INTRODUCTION:The quantitative blood oxygenation level-dependent (qBOLD) method has not become clinically established yet because long acquisition times are necessary to achieve an acceptable certainty of the parameter estimates. In this work, a non-invasive multiparametric (nimp) qBOLD approach based on a simple analyt...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2014.03.009
更新日期：2014-09-01 00:00:00
abstract：:The use of polymer gel makes it possible to measure three-dimensional dose distributions of ionizing radiation. Phantoms with BANG-1 and BANG-3 gel were irradiated using a 68 MeV proton beam at the eye tumour therapy beam line of the Hahn Meitner Institute in Berlin. Up to twelve treatment fields could be applied to o...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00189
更新日期：2004-01-01 00:00:00
abstract：:Low-kV IORT is an increasing modality for breast cancer treatment. Soft X-rays from INTRABEAM (Carl Zeiss Meditec AG, Oberkochen, Germany), a dedicated IORT device along with special spherical applicators are employed for this purpose. A Monte Carlo model of INTRAMBEAM and spherical applicators are introduced in the c...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2019.08.002
更新日期：2020-02-01 00:00:00
abstract：:For selective internal radiation therapy (SIRT) the calculation of the 3D distribution of spheres based on individual blood flow properties is still an open and relevant research question. The purpose of this work is to develop and analyze a new treatment planning method for SIRT to calculate the absorbed dose distrib...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2018.05.006
更新日期：2019-02-01 00:00:00
abstract：:Magnetic resonance imaging (MRI) is ideally suited to monitor minimally invasive operations with catheters or needles, since it offers both a superior soft-tissue contrast and the possibility to perform functional tests. In the present study, small radio-frequency coils were attached to the instruments in order to loc...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00165
更新日期：2003-01-01 00:00:00
abstract：PURPOSE:To review the current limits on the efficacy of radiotherapy (RT) due to technical factors and to assess the potential for major improvements in technology. METHODS AND MATERIALS:The method of this review was to assess the efficacy of current RT in general terms; strategies for improving RT; historical record ...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章,评审
doi：10.1078/0939-3889-00281
更新日期：2005-01-01 00:00:00
abstract：PURPOSE:To determine typical doses from common CT examinations of standard sized adult patients and their variability between CT operators for common CT indications. MATERIALS AND METHODS:In a nationwide Austrian CT dose survey doses from approx. 10,000 common CT examinations of adults during 2009 and 2010 were collec...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2013.12.005
更新日期：2014-09-01 00:00:00
abstract：:A radiotherapy table top was to be designed and manufactured, suitable for computer tomography in the same room. The aim was a distortion of the dose distribution by the table top of not more than 4% in small subunits of the target volume (TV) and less than 2% for the mean dose in the TV. Only negligible artifacts in ...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1078/0939-3889-00212
更新日期：2004-01-01 00:00:00
abstract：:In this work we present a new method to reduce artifacts, produced by high-density objects, especially metal implants, in X-ray cone beam computed tomography (CBCT). These artifacts influence clinical diagnostics and treatments using CT data, if metal objects are located in the field of view (FOV). Our novel method re...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2011.03.002
更新日期：2011-09-01 00:00:00
abstract：BACKGROUND:To increase tumour control probability (TCP) in prostate cancer a method was developed integrating multi-parametric functional and biological information into a dose painting treatment plan aiming focal dose-escalation to tumour sub-volumes. A dose-escalation map was derived considering individual, multi-par...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2016.02.002
更新日期：2017-03-01 00:00:00
abstract：PURPOSE:Online verification and 3D dose reconstruction on daily patient anatomy have the potential to improve treatment delivery, accuracy and safety. One possible implementation is to recalculate dose based on online fluence measurements with a transmission detector (TD) attached to the linac. This study provides a de...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/j.zemedi.2015.08.001
更新日期：2016-09-01 00:00:00
abstract：:Optoacoustic methods are based on the thermoelastic effect, according to which a short laser pulse is absorbed in a medium and generates an acoustic wave following rapid heating and thermal expansion. This study it sought to demonstrate how the optical properties and structure of the sample can be obtained from acoust...
journal_title：Zeitschrift fur medizinische Physik
pub_type： 杂志文章
doi：10.1016/s0939-3889(15)70542-8
更新日期：2002-01-01 00:00:00
