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Introduction:
Radiological equipment quality controls (QC) in presence of many
modalities require an important amount of time for themedical 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 mo-
dality radiology technicians (RTs) acquire and send QC test images to the
server with prearranged periodicity. At the arrival of the image the home-
made 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, evalua-
tion of a parameter correlated to system sensibility, signal uniformity, pixels
out statistics, presence and importance of image artifacts. These param-
eters are filed in an Access relational database; if the procedure notices out-
of-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 radiog-
raphy (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 systemhas allowed to perform image detector and
radiological system QC in a fast and reliable way, reducing the MP workload
andmoreover 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.2016.01.273B.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 examina-
tions 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 an-
giography. 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 ra-
diology 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. Sec-
ondly, 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 Gycm
2
and
1.65 Gy, respectively). We found that 31 procedures exceeded 500 Gycm
2
for DAP and 12 exceeded 5 Gy for air kerma at the entrance reference point.
Conclusions:
For procedures performed in 2014, following the ICRP120 rec-
ommendations, 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 proce-
dures for spinal angiography (highest doses) and for four-vessel angiography
(the most frequent high-doses procedure).
http://dx.doi.org/10.1016/j.ejmp.2016.01.274B.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 Ormezzan
o 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 improve-
ment 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 pharma-
cologic 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 kerma-
area 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 Gycm
2
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 Gycm
2
, 49.1, 52.5, 53.5 e 65.1 Gycm
2
and 815.4, 900, 785.9 and 929.9 mGy.
Conclusions:
Employment of Clarity technology, in case of coronary an-
giography, 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 over-
lapping 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.2016.01.275B.271
GUI SOFTWARE FOR AUTOMATIC DQE CALCULATION IN DIGITAL
RADIOGRAPHY
M. Longo
*
, a ,L. Altabella
b ,M. Bettio
l 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 evalua-
tion 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 fol-
lowing 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 tabu-
lated 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).
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Abstracts/Physica Medica 32 (2016) e71–e96