TY - JOUR AU - Nagy, Ferenc AU - Krizsán, Áron Krisztián AU - Kukuts, Kornel AU - Szolikova, Melinda AU - Hasesi, Zsolt AU - Barna, Sándor Kristóf AU - Acs, Antonietta AU - Szabo, Peter AU - Trón, Lajos AU - Balkay, László AU - Dahlbom, Magnus AU - Zentai, Mihaly AU - Forgács, Attila AU - Garai, Ildikó TI - Q-Bot: automatic DICOM metadata monitoring for the next level of quality management in nuclear medicine JF - EJNMMI PHYSICS J2 - EJNMMI PHYS VL - 8 PY - 2021 IS - 1 PG - 13 SN - 2197-7364 DO - 10.1186/s40658-021-00371-w UR - https://m2.mtmt.hu/api/publication/32599815 ID - 32599815 N1 - 325747 AB - Background Regular and precise inspection of the realization of the local nuclear medicine standard operation procedures (SOPs) is very complex and time-consuming, especially when large amount of patient data is obtained from a wide scale of different scan procedures on a daily basis. DICOM metadata comprise a complete set of data related to the patient and the imaging procedure, and consequently all information necessary to evaluate the compliance with the actual SOP. Methods Q-Bot, an automatic DICOM metadata monitoring tool which is capable to verify SOP conformities, was tested for 11 months at two nuclear medicine departments. Relevant parameters, such as patient ID, patient mass and height, injected activity, and uptake time, were investigated in the case of adult F-18-FDG whole-body PET/CT and Tc-99m-MDP gamma camera bone scans on a daily basis. Q-Bot automatically inspected the actual SOP compliance of these relevant DICOM parameters. Q-Bot graphical user interface (GUI) provided a summary of the outliers in a table format to be investigated by a dedicated technologist. In addition, information related to the error handling was also collected for retrospective analysis of long-term tendencies. Results In total, 6702 PET/CT and 2502 gamma camera scans were inspected, from which 8581 were confirmed as valid patient study without errors. Discrepancies related to the lack of a parameter, not appropriate format, or improper scan procedures were found in 623 cases, and 156 out of these were corrected before the medical reading and reporting. SOP non-conformities explored with Q-Bot were found to be non-correctable in 467 cases. Systematic errors to our practice turned out to be the manual radiopharmaceutical injection, the allowance to use both SI and non-SI units, and the clear definition of decimal point symbol to use. Conclusion The daily evaluation of Q-Bot results provided early detection of errors and consequently ensured the minimization of error propagation. Integration of a QM software that inspects protocol compliance at a nuclear medicine department provides significant support to detect non-conformities for technologists, and much higher confidence in image quality for physicians. LA - English DB - MTMT ER - TY - JOUR AU - Opposits, Gábor AU - Aranyi, Sándor Csaba AU - Glavák, Csaba AU - Cselik, Zsolt AU - Trón, Lajos AU - Sipos, Dávid AU - Hadjiev, Janaki AU - Berényi, Ervin László AU - Repa, Imre AU - Emri, Miklós AU - Kovács, Árpád TI - OAR sparing 3D radiotherapy planning supported by fMRI brain mapping investigations JF - MEDICAL DOSIMETRY J2 - MED DOSIM VL - 45 PY - 2020 IS - 4 SP - e1 EP - e8 SN - 0958-3947 DO - 10.1016/j.meddos.2020.04.003 UR - https://m2.mtmt.hu/api/publication/31336784 ID - 31336784 LA - English DB - MTMT ER - TY - JOUR AU - Forgács, Attila AU - Kallos-Balogh, Piroska AU - Nagy, Ferenc AU - Krizsán, Áron Krisztián AU - Garai, Ildikó AU - Trón, Lajos AU - Dahlbom, Magnus AU - Balkay, László TI - Activity Painting: PET images of freely defined activity distributions applying a novel phantom technique JF - PLOS ONE J2 - PLOS ONE VL - 14 PY - 2019 IS - 1 SP - 1 PG - 14 SN - 1932-6203 DO - 10.1371/journal.pone.0207658 UR - https://m2.mtmt.hu/api/publication/30418465 ID - 30418465 AB - The aim of this work was to develop a novel phantom that supports the construction of highly reproducible phantoms with arbitrary activity distributions for PET imaging. It could offer a methodology for answering questions related to texture measurements in PET imaging. The basic idea is to move a point source on a 3-D trajectory in the field of view, while continuously acquiring data. The reconstruction results in a 3-D activity concentration map according to the pathway of the point source. A Na-22 calibration point source was attached to a high precision robotic arm system, where the 3-D movement was software controlled. 3-D activity distributions of a homogeneous cube, a sphere, a spherical shell and a heart shape were simulated. These distributions were used to measure uniformity and to characterize reproducibility. Two potential applications using the lesion simulation method are presented: evaluation in changes of textural properties related to the position in the PET field of view; scanner comparison based on visual and quantitative evaluation of texture features. A lesion with volume of 50x50x50 mm(3) can be simulated during approximately 1 hour. The reproducibility of the movement was found to be >99%. The coefficients of variation of the voxels within a simulated homogeneous cube was 2.34%. Based on 5 consecutive and independent measurements of a 36 mm diameter hot sphere, the coefficient of variation of the mean activity concentration was 0.68%. We obtained up to 18% differences within the values of investigated textural indexes, when measuring a lesion in different radial positions of the PET field of view. In comparison of two different human PET scanners the percentage differences between heterogeneity parameters were in the range of 5-55%. After harmonizing the voxel sizes this range reduced to 2-16%. The general activity distributions provided by the two different vendor show high similarity visually. For the demonstration of the flexibility of this method, the same pattern was also simulated on a small animal PET scanner giving similar results, both quantitatively and visually. 3-D motion of a point source in the PET field of view is capable to create an irregular shaped activity distribution with high reproducibility. LA - English DB - MTMT ER - TY - JOUR AU - Forgács, Attila AU - Jonsson, H P AU - Dahlbom, M AU - Daver, F AU - DiFranco, M D AU - Opposits, Gábor AU - Krizsán, Áron Krisztián AU - Garai, Ildikó AU - Czernin, J AU - Varga, József AU - Trón, Lajos AU - Balkay, László TI - A Study on the Basic Criteria for Selecting Heterogeneity Parameters of F18-FDG PET Images. JF - PLOS ONE J2 - PLOS ONE VL - 11 PY - 2016 IS - 10 PG - 14 SN - 1932-6203 DO - 10.1371/journal.pone.0164113 UR - https://m2.mtmt.hu/api/publication/3125467 ID - 3125467 N1 - WoS:hiba:000385505800040 2020-09-02 12:00 kötet nem egyezik AB - Textural analysis might give new insights into the quantitative characterization of metabolically active tumors. More than thirty textural parameters have been investigated in former F18-FDG studies already. The purpose of the paper is to declare basic requirements as a selection strategy to identify the most appropriate heterogeneity parameters to measure textural features. Our predefined requirements were: a reliable heterogeneity parameter has to be volume independent, reproducible, and suitable for expressing quantitatively the degree of heterogeneity. Based on this criteria, we compared various suggested measures of homogeneity. A homogeneous cylindrical phantom was measured on three different PET/CT scanners using the commonly used protocol. In addition, a custom-made inhomogeneous tumor insert placed into the NEMA image quality phantom was imaged with a set of acquisition times and several different reconstruction protocols. PET data of 65 patients with proven lung lesions were retrospectively analyzed as well. Four heterogeneity parameters out of 27 were found as the most attractive ones to characterize the textural properties of metabolically active tumors in FDG PET images. These four parameters included Entropy, Contrast, Correlation, and Coefficient of Variation. These parameters were independent of delineated tumor volume (bigger than 25-30 ml), provided reproducible values (relative standard deviation<10%), and showed high sensitivity to changes in heterogeneity. Phantom measurements are a viable way to test the reliability of heterogeneity parameters that would be of interest to nuclear imaging clinicians. LA - English DB - MTMT ER - TY - JOUR AU - Opposits, Gábor AU - Kis, Sándor Attila AU - Trón, Lajos AU - Berényi, Ervin László AU - Takács, Endre AU - Dobai, JG AU - Bognár, László AU - Szucs, B AU - Emri, Miklós TI - Population based ranking of frameless CT-MRI registration methods [Quantifizierung der Qualität von Methoden zur Registrierung von CT- und MRT-Bildern unter Verwendung von Bilddaten eines großen Patientenkollektivs] JF - ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK J2 - Z MED PHYS VL - 25 PY - 2015 IS - 4 SP - 353 EP - 367 PG - 15 SN - 0939-3889 DO - 10.1016/j.zemedi.2015.07.001 UR - https://m2.mtmt.hu/api/publication/2948571 ID - 2948571 AB - BACKGROUND: Clinical practice often requires simultaneous information obtained by two different imaging modalities. Registration algorithms are commonly used for this purpose. Automated procedures are very helpful in cases when the same kind of registration has to be performed on images of a high number of subjects. Radiotherapists would prefer to use the best automated method to assist therapy planning, however there are not accepted procedures for ranking the different registration algorithms. PURPOSE: We were interested in developing a method to measure the population level performance of CT-MRI registration algorithms by a parameter of values in the [0,1] interval. MATERIALS AND METHODS: Pairs of CT and MRI images were collected from 1051 subjects. Results of an automated registration were corrected manually until a radiologist and a neurosurgeon expert both accepted the result as good. This way 1051 registered MRI images were produced by the same pair of experts to be used as gold standards for the evaluation of the performance of other registration algorithms. Pearson correlation coefficient, mutual information, normalized mutual information, Kullback-Leibler divergence, L1 norm and square L2 norm (dis)similarity measures were tested for sensitivity to indicate the extent of (dis)similarity of a pair of individual mismatched images. RESULTS: The square Hellinger distance proved suitable to grade the performance of registration algorithms at population level providing the developers with a valuable tool to rank algorithms. CONCLUSIONS: The developed procedure provides an objective method to find the registration algorithm performing the best on the population level out of newly constructed or available preselected ones. LA - English DB - MTMT ER - TY - JOUR AU - Forgács, Attila AU - Balkay, László AU - Trón, Lajos AU - Raics, Péter TI - Excel2Genie: A Microsoft Excel application to improve the flexibility of the Genie-2000 Spectroscopic software. JF - APPLIED RADIATION AND ISOTOPES J2 - APPL RADIAT ISOTOPES VL - 94 PY - 2014 SP - 77 EP - 81 PG - 5 SN - 0969-8043 DO - 10.1016/j.apradiso.2014.07.005 UR - https://m2.mtmt.hu/api/publication/2721452 ID - 2721452 AB - Excel2Genie, a simple and user-friendly Microsoft Excel interface, has been developed to the Genie-2000 Spectroscopic Software of Canberra Industries. This Excel application can directly control Canberra Multichannel Analyzer (MCA), process the acquired data and visualize them. Combination of Genie-2000 with Excel2Genie results in remarkably increased flexibility and a possibility to carry out repetitive data acquisitions even with changing parameters and more sophisticated analysis. The developed software package comprises three worksheets: display parameters and results of data acquisition, data analysis and mathematical operations carried out on the measured gamma spectra. At the same time it also allows control of these processes. Excel2Genie is freely available to assist gamma spectrum measurements and data evaluation by the interested Canberra users. With access to the Visual Basic Application (VBA) source code of this application users are enabled to modify the developed interface according to their intentions. LA - English DB - MTMT ER - TY - JOUR AU - Lajtos, Imre AU - Czernin, J AU - Dahlbom, M AU - Daver, F AU - Emri, Miklós AU - Farshchi-Heydari, S AU - Forgács, Attila AU - Hoh, CK AU - Jószai, István AU - Krizsán, Áron Krisztián AU - Lantos, J AU - Major, Péter AU - Molnár, József AU - Opposits, Gábor AU - Trón, Lajos AU - Vera, DR AU - Balkay, László TI - Cold wall effect eliminating method to determine the contrast recovery coefficient for small animal PET scanners using the NEMA NU-4 image quality phantom. JF - PHYSICS IN MEDICINE AND BIOLOGY J2 - PHYS MED BIOL VL - 59 PY - 2014 IS - 11 SP - 2727 EP - 2746 PG - 20 SN - 0031-9155 DO - 10.1088/0031-9155/59/11/2727 UR - https://m2.mtmt.hu/api/publication/2586190 ID - 2586190 AB - The contrast recovery coefficients (CRC) were evaluated for five different small animal PET scanners: GE Explore Vista, Genisys4, MiniPET-2, nanoScan PC and Siemens Inveon. The NEMA NU-4 2008 performance test with the suggested image quality phantom (NU4IQ) does not allow the determination of the CRC values for the hot regions in the phantom. This drawback of NU4IQ phantom motivated us to develop a new method for this purpose. The method includes special acquisition and reconstruction protocols using the original phantom, and results in an artificially merged image enabling the evaluation of CRC values. An advantageous feature of this method is that it stops the cold wall effect from distorting the CRC calculation. Our suggested protocol results in a set of CRC values contributing to the characterization of small animal PET scanners. GATE simulations were also performed to validate the new method and verify the evaluated CRC values. We also demonstrated that the numerical values of this parameter depend on the actual object contrast of the hot region(s) and this mainly comes from the spillover effect. This effect was also studied while analysing the background activity level around the hot rods. We revealed that the calculated background mean values depended on the target contrast in a scanner specific manner. Performing the artificially merged imaging procedure and additional simulations using the micro hollow sphere (MHS) phantom geometry, we also proved that the inactive wall around the hot spheres can have a remarkable impact on the calculated CRC. In conclusion, we have shown that the proposed artificial merging procedure and the commonly used NU4IQ phantom prescribed by the NEMA NU-4 can easily deliver reliable CRC data otherwise unavailable for the NU4IQ phantom in the conventional protocol or the MHS phantom. LA - English DB - MTMT ER - TY - JOUR AU - Lajtos, Imre AU - Emri, Miklós AU - Trón, Lajos AU - Kis, Sándor Attila AU - Opposits, Gábor AU - Márián, Teréz AU - Trencsényi, György AU - Mikecz, Pál AU - Spisák, Tamás AU - Krizsán, Áron Krisztián AU - Molnár, József AU - Hegyesi, Gyula AU - Kalinka, Gábor AU - Valastyán, Iván AU - Király, Beáta AU - Balkay, L TI - A debreceni kisállat PET program eredményei: A MiniPET-1, MiniPET-2 és a MiniPET-3 kamerák leképezési tulajdonságai. (in Hung.) IME - Az egészségügyi vezetôk szaklapja. Képalkotó különszám 12 (2013)33-38 JF - IME J2 - IME VL - 12 PY - 2013 IS - Képalkotó különszám SP - 33 EP - 38 PG - 6 SN - 1588-6387 UR - https://m2.mtmt.hu/api/publication/2522941 ID - 2522941 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Lajtos, Imre AU - Emri, Miklós AU - Kis, Sándor Attila AU - Opposits, Gábor AU - Pótári, Norbert AU - Király, Beáta AU - Nagy, Ferenc AU - Trón, Lajos AU - Balkay, László TI - Performance evaluation and optimization of the MiniPET-II scanner JF - NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT J2 - NUCL INSTRUM METH A VL - 707 PY - 2013 IS - 0 SP - 26 EP - 34 PG - 9 SN - 0168-9002 DO - 10.1016/j.nima.2012.12.079 UR - https://m2.mtmt.hu/api/publication/2185221 ID - 2185221 LA - English DB - MTMT ER - TY - JOUR AU - Kis, Sándor Attila AU - Opposits, Gábor AU - Lajtos, Imre AU - Spisák, Tamás AU - Balkay, László AU - Kovács, György AU - Trón, Lajos AU - Emri, Miklós TI - Comparative analysis of image processing algorithms on quadratic and hexagonal grids JF - EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING J2 - EUR J NUCL MED MOL I VL - 38 PY - 2011 IS - 2 SP - S275 EP - S275 PG - 1 SN - 1619-7070 UR - https://m2.mtmt.hu/api/publication/2326019 ID - 2326019 LA - English DB - MTMT ER -