- Email: [email protected]
Retrospective analysis of angiographic procedures: Dosimetric evaluation
e80
Abstracts/Physica Medica 32 (2016) e71–e96
Introduction: Radiological equipment quality controls (QC) in presence of many modalities require an important amount of time for the medical physicist (MP), both for measurements and data analysis, and can obstruct clinical workflow. Therefore an automatic image analysis system has been developed to verify the correct operation of radiological systems with the desired periodicity. Materials and Methods: The diagnostic modalities of our institution are connected to the server of the Medical Physics department. For each modality radiology technicians (RTs) acquire and send QC test images to the server with prearranged periodicity. At the arrival of the image the homemade automatic system developed in Visual Studio environment reads the image DICOM file and analyses the image. The following parameters are calculated: effective number of bits per pixel, low quality edge areas, noise distribution and mean value, mean signal, signal to noise ratio, evaluation of a parameter correlated to system sensibility, signal uniformity, pixels out statistics, presence and importance of image artifacts. These parameters are filed in an Access relational database; if the procedure notices outof-tolerance parameters, an alert e-mail is automatically sent to the MP responsible for the QC. Results: In our institution the procedure has analyzed around 1000 images since 2010. Currently, mammography equipments are checked at least twice a month. Computed radiography (CR) detectors and direct digital radiography (DR) systems are checked annually or when the RTs consider it necessary. Frequent mammography QC has turned out to be effective in showing possible malfunctioning promptly. Conclusions: The described system has allowed to perform image detector and radiological system QC in a fast and reliable way, reducing the MP workload and moreover allowing frequent QC without obstructing clinical workflow. We are planning to increase QC periodicity also for the other modalities. http://dx.doi.org/10.1016/j.ejmp.2016.01.273
B.269 RETROSPECTIVE ANALYSIS OF ANGIOGRAPHIC PROCEDURES: DOSIMETRIC EVALUATION S. Guariglia *, G. Meliadò, S. Montemezzi, C. Cavedon. Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy Introduction: Angiographic procedures and CT scans are the examinations that give the highest doses to the patient in Radiology. The aim of this work is to introduce a system of follow-up and in vivo dosimetry for patients that undergo high-dose angiographic procedures. Material and Methods: In our hospital 7 X-ray systems are used for angiography. On four of them it was possible to install a system that sends the relevant parameters to a control node via e-mail once a procedure has been completed. The different machines are used by different physicians for specific tasks: electrophysiology, neuroradiology, hemodynamics and interventional radiology procedures, respectively. In this work, data of procedures performed in one year (2014) have been analyzed. First, we converted the structured e-mail information into text file. Secondly, we created a software that could extract the relevant data automatically. Finally, data analysis was performed. The following information were extracted: patient name and ID, date and duration of procedure, performing physician, cumulative air kerma and total DAP. Results: In 2014, 1366 angiographic procedures were performed on these angiographic systems. The majority of procedures were performed for interventional radiology (36.3%) and the highest mean values for DAP and air kerma were observed in neuroradiology procedures (206 Gycm2 and 1.65 Gy, respectively). We found that 31 procedures exceeded 500 Gycm2 for DAP and 12 exceeded 5 Gy for air kerma at the entrance reference point. Conclusions: For procedures performed in 2014, following the ICRP120 recommendations, 34 patients should have had a follow up for detection of potential injuries. Based on the results of this study, in the future we will follow up or perform in vivo dosimetry for patients that undergo procedures for spinal angiography (highest doses) and for four-vessel angiography (the most frequent high-doses procedure). http://dx.doi.org/10.1016/j.ejmp.2016.01.274
B.270 INTERVENTIONAL CARDIOLOGY: COMPARISON OF DATA FROM THREE CENTERS WITH SIMILAR TECHNOLOGY P. Isoardi * ,a , L. D’Ercole b , C. Giordano c , F. Gaita a , S. Marra a , M. Ferrario Ormezzano b, F. Passerini c. a A.O.U. Città della Salute e della Scienza di Torino, Torino, Italy; b Fondazione IRCCS Policlinico S. Matteo Pavia, Pavia, Italy; c AUSL Piacenza, Piacenza, Italy Introduction: Interventional cardiology is hardly affected from improvement of pharmacology and technology. Dosimetric data from Cardiac Catheterization Laboratory have been compared among centers with similar angiographic systems for verifying if technologic innovation and pharmacologic progress involve a real dose sparing to patient. Material and Methods: A total of 433 coronary angiography (CA) and 408 percutaneous transluminal coronary angioplasty (PTCA), were analyzed, from three Italian Hospitals and four angiographic systems FD10 Philips Allura, one of which with Clarity technology. We compared cumulative air kermaarea product (PKA), PKAGRAPHY, cumulative air kerma and fluoroscopy time. Results: For coronary angiography, median values for fluoroscopy time, PKAGRAPHY, PKA and cumulative air kerma are the following : 4.4, 4.4, 5.0 e 1.6 min; 10.5, 8.6, 15.5 and 21.9 Gycm2, 17.5, 14.5, 22.5 e 31.2 Gycm2 and 271.6, 223.5, 349.1 e 382.7 mGy; for PTCA respectively: 13, 17.5, 12 and 8.5 min, 23.3, 24.7, 30.9 and 24.6 Gycm2, 49.1, 52.5, 53.5 e 65.1 Gycm2 and 815.4, 900, 785.9 and 929.9 mGy. Conclusions: Employment of Clarity technology, in case of coronary angiography, permits of decrease patient exposure in terms of PKAGRAPHY and of cumulative air kerma; in procedures of angioplasty, median value of cumulative air kerma for the system with Clarity technology is either comparable with the system without Clarity technology or is higher of 10– 15%. The failure of dose reduction could be derived, in first analysis, from the fact that in that system, have been introduced the StentBoost (SB) and the StentBoost Subtract (SBSub) that improve the view of stent through overlapping of angiographic multiple images: SB acquires images at 30 fps for 30 frames, while SBSub acquires at 15 fps for up 30 seconds. http://dx.doi.org/10.1016/j.ejmp.2016.01.275
B.271 GUI SOFTWARE FOR AUTOMATIC DQE CALCULATION IN DIGITAL RADIOGRAPHY M. Longo *,a, L. Altabella b, M. Bettiol c, R. Donnarumma a,d, C. Orlandi e, M. Carni’ f, E. Di Castro d,f. a Post Graduate School of Medical Physics, Sapienza University of Rome, Rome, Italy; b Medical Physics Department, San Raffaele Scientific Institute, Milan, Italy; c Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy; d INFN Roma I Section, Rome, Italy; e Medical Physics Department, Enterprise Risk Management, Bambino Gesù Children’s Hospital, Rome, Italy; f Department of Radiological Sciences, Health Physic Unit, Sapienza University of Rome, Rome, Italy Introduction: In recent years, the increasing sophistication of digital imaging devices led to the necessity to develop specific quality control tests for the quantitative assessment of image quality. In this field, a series of parameters related to image quality, such as Detective Quantum Efficiency (DQE), Noise Power Spectrum (NPS) and Modulation Transfer Function (MTF) are considered the best metric for image quality evaluation in digital detectors. The aim of this work is to develop a software for assisting users in achieving DQE calculation in digital radiography (DR). Materials and Methods: To this aim, Graphical User Interface (GUI) was implemented in MATLAB environment. All parameters were evaluated following the indications provided by IEC standard 62220-1. Firstly, the system response function has to be determined by acquiring one image for each exposure level in a range compatible with clinical conditions. Secondly, MTF is evaluated using the edge technique, extracting and oversampling the Edge Spread Function (ESF) from image profiles. For DQE calculation, the NPS at the detector surface has to be known. Its value per air kerma is tabulated for a series of radiation qualities. NPS at the output of the digital x-ray imaging device is estimated by processing a set of flat-field images at the examined exposures. The program requires DICOM images as input: slightly angled edge images and flat-field images. The software was tested on a DR system (Trixel pixium RF 4343).
Abstracts/Physica Medica 32 (2016) e71–e96
Introduction: Radiological equipment quality controls (QC) in presence of many modalities require an important amount of time for the medical physicist (MP), both for measurements and data analysis, and can obstruct clinical workflow. Therefore an automatic image analysis system has been developed to verify the correct operation of radiological systems with the desired periodicity. Materials and Methods: The diagnostic modalities of our institution are connected to the server of the Medical Physics department. For each modality radiology technicians (RTs) acquire and send QC test images to the server with prearranged periodicity. At the arrival of the image the homemade automatic system developed in Visual Studio environment reads the image DICOM file and analyses the image. The following parameters are calculated: effective number of bits per pixel, low quality edge areas, noise distribution and mean value, mean signal, signal to noise ratio, evaluation of a parameter correlated to system sensibility, signal uniformity, pixels out statistics, presence and importance of image artifacts. These parameters are filed in an Access relational database; if the procedure notices outof-tolerance parameters, an alert e-mail is automatically sent to the MP responsible for the QC. Results: In our institution the procedure has analyzed around 1000 images since 2010. Currently, mammography equipments are checked at least twice a month. Computed radiography (CR) detectors and direct digital radiography (DR) systems are checked annually or when the RTs consider it necessary. Frequent mammography QC has turned out to be effective in showing possible malfunctioning promptly. Conclusions: The described system has allowed to perform image detector and radiological system QC in a fast and reliable way, reducing the MP workload and moreover allowing frequent QC without obstructing clinical workflow. We are planning to increase QC periodicity also for the other modalities. http://dx.doi.org/10.1016/j.ejmp.2016.01.273
B.269 RETROSPECTIVE ANALYSIS OF ANGIOGRAPHIC PROCEDURES: DOSIMETRIC EVALUATION S. Guariglia *, G. Meliadò, S. Montemezzi, C. Cavedon. Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy Introduction: Angiographic procedures and CT scans are the examinations that give the highest doses to the patient in Radiology. The aim of this work is to introduce a system of follow-up and in vivo dosimetry for patients that undergo high-dose angiographic procedures. Material and Methods: In our hospital 7 X-ray systems are used for angiography. On four of them it was possible to install a system that sends the relevant parameters to a control node via e-mail once a procedure has been completed. The different machines are used by different physicians for specific tasks: electrophysiology, neuroradiology, hemodynamics and interventional radiology procedures, respectively. In this work, data of procedures performed in one year (2014) have been analyzed. First, we converted the structured e-mail information into text file. Secondly, we created a software that could extract the relevant data automatically. Finally, data analysis was performed. The following information were extracted: patient name and ID, date and duration of procedure, performing physician, cumulative air kerma and total DAP. Results: In 2014, 1366 angiographic procedures were performed on these angiographic systems. The majority of procedures were performed for interventional radiology (36.3%) and the highest mean values for DAP and air kerma were observed in neuroradiology procedures (206 Gycm2 and 1.65 Gy, respectively). We found that 31 procedures exceeded 500 Gycm2 for DAP and 12 exceeded 5 Gy for air kerma at the entrance reference point. Conclusions: For procedures performed in 2014, following the ICRP120 recommendations, 34 patients should have had a follow up for detection of potential injuries. Based on the results of this study, in the future we will follow up or perform in vivo dosimetry for patients that undergo procedures for spinal angiography (highest doses) and for four-vessel angiography (the most frequent high-doses procedure). http://dx.doi.org/10.1016/j.ejmp.2016.01.274
B.270 INTERVENTIONAL CARDIOLOGY: COMPARISON OF DATA FROM THREE CENTERS WITH SIMILAR TECHNOLOGY P. Isoardi * ,a , L. D’Ercole b , C. Giordano c , F. Gaita a , S. Marra a , M. Ferrario Ormezzano b, F. Passerini c. a A.O.U. Città della Salute e della Scienza di Torino, Torino, Italy; b Fondazione IRCCS Policlinico S. Matteo Pavia, Pavia, Italy; c AUSL Piacenza, Piacenza, Italy Introduction: Interventional cardiology is hardly affected from improvement of pharmacology and technology. Dosimetric data from Cardiac Catheterization Laboratory have been compared among centers with similar angiographic systems for verifying if technologic innovation and pharmacologic progress involve a real dose sparing to patient. Material and Methods: A total of 433 coronary angiography (CA) and 408 percutaneous transluminal coronary angioplasty (PTCA), were analyzed, from three Italian Hospitals and four angiographic systems FD10 Philips Allura, one of which with Clarity technology. We compared cumulative air kermaarea product (PKA), PKAGRAPHY, cumulative air kerma and fluoroscopy time. Results: For coronary angiography, median values for fluoroscopy time, PKAGRAPHY, PKA and cumulative air kerma are the following : 4.4, 4.4, 5.0 e 1.6 min; 10.5, 8.6, 15.5 and 21.9 Gycm2, 17.5, 14.5, 22.5 e 31.2 Gycm2 and 271.6, 223.5, 349.1 e 382.7 mGy; for PTCA respectively: 13, 17.5, 12 and 8.5 min, 23.3, 24.7, 30.9 and 24.6 Gycm2, 49.1, 52.5, 53.5 e 65.1 Gycm2 and 815.4, 900, 785.9 and 929.9 mGy. Conclusions: Employment of Clarity technology, in case of coronary angiography, permits of decrease patient exposure in terms of PKAGRAPHY and of cumulative air kerma; in procedures of angioplasty, median value of cumulative air kerma for the system with Clarity technology is either comparable with the system without Clarity technology or is higher of 10– 15%. The failure of dose reduction could be derived, in first analysis, from the fact that in that system, have been introduced the StentBoost (SB) and the StentBoost Subtract (SBSub) that improve the view of stent through overlapping of angiographic multiple images: SB acquires images at 30 fps for 30 frames, while SBSub acquires at 15 fps for up 30 seconds. http://dx.doi.org/10.1016/j.ejmp.2016.01.275
B.271 GUI SOFTWARE FOR AUTOMATIC DQE CALCULATION IN DIGITAL RADIOGRAPHY M. Longo *,a, L. Altabella b, M. Bettiol c, R. Donnarumma a,d, C. Orlandi e, M. Carni’ f, E. Di Castro d,f. a Post Graduate School of Medical Physics, Sapienza University of Rome, Rome, Italy; b Medical Physics Department, San Raffaele Scientific Institute, Milan, Italy; c Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy; d INFN Roma I Section, Rome, Italy; e Medical Physics Department, Enterprise Risk Management, Bambino Gesù Children’s Hospital, Rome, Italy; f Department of Radiological Sciences, Health Physic Unit, Sapienza University of Rome, Rome, Italy Introduction: In recent years, the increasing sophistication of digital imaging devices led to the necessity to develop specific quality control tests for the quantitative assessment of image quality. In this field, a series of parameters related to image quality, such as Detective Quantum Efficiency (DQE), Noise Power Spectrum (NPS) and Modulation Transfer Function (MTF) are considered the best metric for image quality evaluation in digital detectors. The aim of this work is to develop a software for assisting users in achieving DQE calculation in digital radiography (DR). Materials and Methods: To this aim, Graphical User Interface (GUI) was implemented in MATLAB environment. All parameters were evaluated following the indications provided by IEC standard 62220-1. Firstly, the system response function has to be determined by acquiring one image for each exposure level in a range compatible with clinical conditions. Secondly, MTF is evaluated using the edge technique, extracting and oversampling the Edge Spread Function (ESF) from image profiles. For DQE calculation, the NPS at the detector surface has to be known. Its value per air kerma is tabulated for a series of radiation qualities. NPS at the output of the digital x-ray imaging device is estimated by processing a set of flat-field images at the examined exposures. The program requires DICOM images as input: slightly angled edge images and flat-field images. The software was tested on a DR system (Trixel pixium RF 4343).