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Patient radiation dose in interventional cardiology procedures performed in Modena Local Health Unit
Abstracts/Physica Medica 32 (2016) e71–e96
B.322 A NEW METHOD FOR THE ANATOMICAL DISTRICT RECOGNITION (ADR) IN CT IMAGES A. Vassena *,a, G. Pozzi b, A. Ostinelli a. a A.O. Sant’Anna, Como, Italy; b DEIB Politecnico di Milano, Milano, Italy Introduction: Use of bio-medical images in clinical practice is becoming more and more frequent and relevant. Despite standard image formats including alpha-numerical tags, the anatomical district description may be incomplete, missing, or even erroneous. We propose a novel approach based on CT scout images (ADR), to identify the anatomical districts in CT examinations. Materials and Methods: ADR exploits the Histogram of Oriented Gradients (HOG) method implemented by Matlab 2010b. The method, based on feature detection, normalizes the image, and then splits it into cells. For every cell, the method computes the gradient [0–179 deg.] of its pixels and builds up the HOG for the image, obtaining a Feature Vector (FV). For every image, we then compare that FV with the FVs of references images we previously manually classified. By looking for the minimal difference between FVs (identified by Least Squares) we classify any image. Results: For head, chest and abdomen districts the sensitivity results are 99.5%, 91.5%, 95.0% and 100%, 80.5%, 81.0 % for front and side scout, respectively. In the same way, the accuracy results were 98%, 97%, 96% and 98%, 100%, 99% respectively. Methods from the literature resulted in a poor sensitivity (<80% in most cases). Computing time was also considered: for our workload of 73 CT images/day, a 2 h 1 min overall processing time is needed. Conclusions: ADR defines a novel approach in anatomical district classification featuring an improved accuracy and sensitivity with respect to methods from the literature. Future implementations are related to: optimized repository, integrating dose assessment system and automatically running the classifier on the images stored by the PACS system. http://dx.doi.org/10.1016/j.ejmp.2016.01.327
B.323 PATIENT RADIATION DOSE IN INTERVENTIONAL CARDIOLOGY PROCEDURES PERFORMED IN MODENA LOCAL HEALTH UNIT G. Venturi *, F. Goldoni, D. Acchiappati. S.C Fisica Medica, AUSL Modena, Italy Introduction: The aim of this work, which was carried on in collaboration with the Medical Imaging Department and Cardiology Department of the Nuovo Ospedale Sant’Agostino in Modena, and became part of a larger Survey, is the dosimetric characterization of interventional cardiology procedures performed by the hemodynamic laboratory. We examined diagnostic coronary angiography and percutaneous transluminal coronary angioplasty procedures with the standard dosimetry indicators (DAP and fluoroscopy time), and then evaluated the dose to the organs by using Monte Carlo simulations and anthropomorphic phantom with thermoluminescent dosimeters. Materials and Methods: These dosimetric evaluations were part of a project that included an educational component addressed to the x-ray technicians, and were conducted by examining the activity of the hemodynamic laboratory over the course of a year and on a sample of about 1800 patients. Information were collected about the type of procedure performed, the composition of the team executing the procedure, the type of patient (height and weight) and the dosimetric indicators (DAP and fluoroscopy time). The coronary angiography procedure was evaluated by studying the dosimetric contribution of every projection. Results and Conclusions: The final results confirm the good level of optimization of the various operative protocols of the hospital and the full respect of the Diagnostic Reference Levels, and provide a good estimation of the dose that the patient’s organs received, even in relation to the type or projections utilized during the procedures. http://dx.doi.org/10.1016/j.ejmp.2016.01.328
B.324 DIAGNOSTIC RADIATION DOSE IN ADULT TRAUMA PATIENTS: A SURVEY PERFORMED AT MODENA LOCAL HEALTH UNIT G. Venturi *,a, C. Malagoli a, D. Acchiappati a, G. Bandiera b, L. Vallisneri a. a S.C Fisica Medica, AUSL Modena, Italy; b Dipartimento Di Emergenza, AUSL Modena, Italy
e95
Introduction: Diagnostic Imaging is essential to evaluate the conditions of those patients who are transported to the Emergency Department following multiple traumas. Often combined with conventional radiology, CT scan is certainly one of the most utilized procedures for the diagnosis. Depending on the type of trauma and the patient’s developing conditions, radiological examinations must often be repeated, resulting in high radiation dose for the ER patients. The objective of this study is to identify diagnostic paths for the various types of polytrauma and estimate for each of them the dose to the organs for the patient. Materials and Methods: The survey was performed on a sample of 355 patients. All of them suffered major trauma (Injury Severity Score > 15) and where brought to the Emergency Department of Sant’Agostino Estense Hospital in 2012. A Regional database with data pertaining to the activation of the trauma team provided the patients’ anagraphical information and gave some useful information about the type of injury suffered by the patient. Many different typologies of trauma were identified (the principal ones are cranial, thoracic, abdominal, arms and legs) alongside with related diagnostic path. It was identified for each type of trauma object of study a patient who has been subjected to a median number of RX and TC examinations. The dosimetric evaluations were performed using the Monte Carlo software PCXMC and ImPACT. Results and Conclusions: Notwithstanding the possibly high exposure to ionizing radiations, diagnostic imaging is certainly justifiable given the life threatening nature of polytraumas. However, an accurate dosimetric evaluation for each diagnostic path is an important piece of information for the doctors of Emergency Department, as well as for the communication of the dosimetric data to patients and them caregivers. http://dx.doi.org/10.1016/j.ejmp.2016.01.329
B.325 EFFECT OF DIFFERENT FRAME RATES ON LOW CONTRAST DETECTABILITY IN DIGITAL ANGIOGRAPHY R. Villa *,a,b, C. Spadavecchia a,b, A. Radice b, C. Pasquali b, N. Paruccini b, A. Crespi b. a Scuola di Specializzazione in Fisica Medica, UNIMI, Milano, Italy; b A.O. San Gerardo, S.C. Fisica Sanitaria, Monza, Italy Introduction: digital angiography systems produce different kinds of images: fluoroscopic images obtained with low mA values, coronary angiography images acquired with very high mA values besides very short times and DSA images obtained through image subtraction. All these images are dynamic ones and have to be analysed in motion. The analysis of low contrast detail characteristics of the above-mentioned images achieved with standard phantom is difficult and time-consuming. Materials and Methods: LCD was estimated applying Chao’s statistical method and using a dedicated phantom. LCD values were calculated frame by frame. Therefore we arranged a 4AFC experiment adding low contrast details to a uniform region of fluoroscopy and fluorography runs acquired. Results: details detectability depended on the viewing frame rate: higher rates showed better details detectability. Contrast detail curves derived from perception experiment were compared with LCD curve calculated on a single frame and on images obtained as a mean of different numbers of frames. Our results agreed with the assumption that the time of integration of noise in human retina is 200 ms. For example contrast detail values obtained with a viewing frame rate of 15 fps were in agreement with LCD calculated on an image which was a mean of three different frames. Conclusions: the statistical approach proved to be less time-consuming, independent on inter- and intra-observers variability and repeatable, thus being a valid method for image quality (or LCD) assessment and is currently adopted in image quality assurance protocols. http://dx.doi.org/10.1016/j.ejmp.2016.01.330
B.322 A NEW METHOD FOR THE ANATOMICAL DISTRICT RECOGNITION (ADR) IN CT IMAGES A. Vassena *,a, G. Pozzi b, A. Ostinelli a. a A.O. Sant’Anna, Como, Italy; b DEIB Politecnico di Milano, Milano, Italy Introduction: Use of bio-medical images in clinical practice is becoming more and more frequent and relevant. Despite standard image formats including alpha-numerical tags, the anatomical district description may be incomplete, missing, or even erroneous. We propose a novel approach based on CT scout images (ADR), to identify the anatomical districts in CT examinations. Materials and Methods: ADR exploits the Histogram of Oriented Gradients (HOG) method implemented by Matlab 2010b. The method, based on feature detection, normalizes the image, and then splits it into cells. For every cell, the method computes the gradient [0–179 deg.] of its pixels and builds up the HOG for the image, obtaining a Feature Vector (FV). For every image, we then compare that FV with the FVs of references images we previously manually classified. By looking for the minimal difference between FVs (identified by Least Squares) we classify any image. Results: For head, chest and abdomen districts the sensitivity results are 99.5%, 91.5%, 95.0% and 100%, 80.5%, 81.0 % for front and side scout, respectively. In the same way, the accuracy results were 98%, 97%, 96% and 98%, 100%, 99% respectively. Methods from the literature resulted in a poor sensitivity (<80% in most cases). Computing time was also considered: for our workload of 73 CT images/day, a 2 h 1 min overall processing time is needed. Conclusions: ADR defines a novel approach in anatomical district classification featuring an improved accuracy and sensitivity with respect to methods from the literature. Future implementations are related to: optimized repository, integrating dose assessment system and automatically running the classifier on the images stored by the PACS system. http://dx.doi.org/10.1016/j.ejmp.2016.01.327
B.323 PATIENT RADIATION DOSE IN INTERVENTIONAL CARDIOLOGY PROCEDURES PERFORMED IN MODENA LOCAL HEALTH UNIT G. Venturi *, F. Goldoni, D. Acchiappati. S.C Fisica Medica, AUSL Modena, Italy Introduction: The aim of this work, which was carried on in collaboration with the Medical Imaging Department and Cardiology Department of the Nuovo Ospedale Sant’Agostino in Modena, and became part of a larger Survey, is the dosimetric characterization of interventional cardiology procedures performed by the hemodynamic laboratory. We examined diagnostic coronary angiography and percutaneous transluminal coronary angioplasty procedures with the standard dosimetry indicators (DAP and fluoroscopy time), and then evaluated the dose to the organs by using Monte Carlo simulations and anthropomorphic phantom with thermoluminescent dosimeters. Materials and Methods: These dosimetric evaluations were part of a project that included an educational component addressed to the x-ray technicians, and were conducted by examining the activity of the hemodynamic laboratory over the course of a year and on a sample of about 1800 patients. Information were collected about the type of procedure performed, the composition of the team executing the procedure, the type of patient (height and weight) and the dosimetric indicators (DAP and fluoroscopy time). The coronary angiography procedure was evaluated by studying the dosimetric contribution of every projection. Results and Conclusions: The final results confirm the good level of optimization of the various operative protocols of the hospital and the full respect of the Diagnostic Reference Levels, and provide a good estimation of the dose that the patient’s organs received, even in relation to the type or projections utilized during the procedures. http://dx.doi.org/10.1016/j.ejmp.2016.01.328
B.324 DIAGNOSTIC RADIATION DOSE IN ADULT TRAUMA PATIENTS: A SURVEY PERFORMED AT MODENA LOCAL HEALTH UNIT G. Venturi *,a, C. Malagoli a, D. Acchiappati a, G. Bandiera b, L. Vallisneri a. a S.C Fisica Medica, AUSL Modena, Italy; b Dipartimento Di Emergenza, AUSL Modena, Italy
e95
Introduction: Diagnostic Imaging is essential to evaluate the conditions of those patients who are transported to the Emergency Department following multiple traumas. Often combined with conventional radiology, CT scan is certainly one of the most utilized procedures for the diagnosis. Depending on the type of trauma and the patient’s developing conditions, radiological examinations must often be repeated, resulting in high radiation dose for the ER patients. The objective of this study is to identify diagnostic paths for the various types of polytrauma and estimate for each of them the dose to the organs for the patient. Materials and Methods: The survey was performed on a sample of 355 patients. All of them suffered major trauma (Injury Severity Score > 15) and where brought to the Emergency Department of Sant’Agostino Estense Hospital in 2012. A Regional database with data pertaining to the activation of the trauma team provided the patients’ anagraphical information and gave some useful information about the type of injury suffered by the patient. Many different typologies of trauma were identified (the principal ones are cranial, thoracic, abdominal, arms and legs) alongside with related diagnostic path. It was identified for each type of trauma object of study a patient who has been subjected to a median number of RX and TC examinations. The dosimetric evaluations were performed using the Monte Carlo software PCXMC and ImPACT. Results and Conclusions: Notwithstanding the possibly high exposure to ionizing radiations, diagnostic imaging is certainly justifiable given the life threatening nature of polytraumas. However, an accurate dosimetric evaluation for each diagnostic path is an important piece of information for the doctors of Emergency Department, as well as for the communication of the dosimetric data to patients and them caregivers. http://dx.doi.org/10.1016/j.ejmp.2016.01.329
B.325 EFFECT OF DIFFERENT FRAME RATES ON LOW CONTRAST DETECTABILITY IN DIGITAL ANGIOGRAPHY R. Villa *,a,b, C. Spadavecchia a,b, A. Radice b, C. Pasquali b, N. Paruccini b, A. Crespi b. a Scuola di Specializzazione in Fisica Medica, UNIMI, Milano, Italy; b A.O. San Gerardo, S.C. Fisica Sanitaria, Monza, Italy Introduction: digital angiography systems produce different kinds of images: fluoroscopic images obtained with low mA values, coronary angiography images acquired with very high mA values besides very short times and DSA images obtained through image subtraction. All these images are dynamic ones and have to be analysed in motion. The analysis of low contrast detail characteristics of the above-mentioned images achieved with standard phantom is difficult and time-consuming. Materials and Methods: LCD was estimated applying Chao’s statistical method and using a dedicated phantom. LCD values were calculated frame by frame. Therefore we arranged a 4AFC experiment adding low contrast details to a uniform region of fluoroscopy and fluorography runs acquired. Results: details detectability depended on the viewing frame rate: higher rates showed better details detectability. Contrast detail curves derived from perception experiment were compared with LCD curve calculated on a single frame and on images obtained as a mean of different numbers of frames. Our results agreed with the assumption that the time of integration of noise in human retina is 200 ms. For example contrast detail values obtained with a viewing frame rate of 15 fps were in agreement with LCD calculated on an image which was a mean of three different frames. Conclusions: the statistical approach proved to be less time-consuming, independent on inter- and intra-observers variability and repeatable, thus being a valid method for image quality (or LCD) assessment and is currently adopted in image quality assurance protocols. http://dx.doi.org/10.1016/j.ejmp.2016.01.330