TY  - JOUR
A1  - Weckesser, Martin
A1  - Grießmeier, Martin
A1  - Schmidt, Daniela
A1  - Sonnenberg, Frank
A1  - Ziemons, Karl
A1  - Kemna, Lars
A1  - Holschbach, Marcus
A1  - Langen, Karl-J.
A1  - Müller-Gärtner, Hans-W.
T1  - Iodine-123 α-methyl tyrosine single-photon emission tomography of cerebral gliomas: standardised evaluation of tumour uptake and extent
JF  - European Journal of Nuclear Medicine
N2  - Single-photon emission tomography (SPET) with the amino acid analogue l-3-[123I]iodo-α-methyl tyrosine (IMT) is helpful in the diagnosis and monitoring of cerebral gliomas. Radiolabelled amino acids seem to reflect tumour infiltration more specifically than conventional methods like magnetic resonance imaging and computed tomography. Automatic tumour delineation based on maximal tumour uptake may cause an overestimation of mean tumour uptake and an underestimation of tumour extension in tumours with circumscribed peaks. The aim of this study was to develop a program for tumour delineation and calculation of mean tumour uptake which takes into account the mean background activity and is thus optimised to the problem of tumour definition in IMT SPET. Using the frequency distribution of pixel intensities of the tomograms a program was developed which automatically detects a reference brain region and draws an isocontour region around the tumour taking into account mean brain radioactivity. Tumour area and tumour/brain ratios were calculated. A three-compartment phantom was simulated to test the program. The program was applied to IMT SPET studies of 20 patients with cerebral gliomas and was compared to the results of manual analysis by three different investigators. Activity ratios and chamber extension of the phantom were correctly calculated by the automatic analysis. A method based on image maxima alone failed to determine chamber extension correctly. Manual region of interest analysis in patient studies resulted in a mean inter-observer standard deviation of 8.7%±6.1% (range 2.7%–25.0%). The mean value of the results of the manual analysis showed a significant correlation to the results of the automatic analysis (r = 0.91, P<0.0001 for the uptake ratio; r = 0.87, P<0.0001 for the tumour area). We conclude that the algorithm proposed simplifies the calculation of uptake ratios and may be used for observer-independent evaluation of IMT SPET studies. Three-dimensional tumour recognition and transfer to co-registered morphological images based on this program may be useful for the planning of surgical and radiation treatment.
Y1  - 1998
SN  - 1619-7089
VL  - 25
IS  - 2
SP  - 150
EP  - 156
ER  - 
TY  - JOUR
A1  - Kleines, H.
A1  - Ziemons, Karl
A1  - Zwoll, K.
T1  - Experiences with ATM in a multivendor pilot system at Forschungszentrum Jülich
JF  - IEEE Transactions on Nuclear Science
N2  - The ATM technology for high speed serial transmission provides a new quality of communication by introducing novel features in a LAN environment, especially support of real time communication, of both LAN and WAN communication and of multimedia streams. In order to evaluate ATM for future DAQ systems and remote control systems as well as for a high speed picture archiving and communications system for medical images, Forschungszentrum Julich has build up a pilot system for the evaluation of ATM and standard low cost multimedia systems. It is a heterogeneous multivendor system containing a variety of switches and desktop solutions, employing different protocol options of ATM. The tests conducted in the pilot system revealed major difficulties regarding stability, interoperability and performance. The paper presents motivations, layout and results of the pilot system. Discussion of results concentrates on performance issues relevant for realistic applications, e.g., connection to a RAID system via NFS over ATM
Y1  - 1998
SN  - 0018-9499
VL  - 45
IS  - 4
SP  - 1867
EP  - 1871
ER  -