Physica Medica: European Journal of Medical Physics - Volume 32 - Supplement 1 - February 2016

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CATPHAN using the tungsten bead and noise was evaluated as standard
deviation of CT number on the water phantom at each dose.
Results: Both ASIR and ASIR-V, in comparison to FBP, showed progressive
shift (15%–45%) on NPS towards low frequencies with increasing IR% while
greater shift was seen for VEO. MTF curves for ASIR and ASIR-V were similar
to FBP, whereas VEO significantly improved MTF. ASIR-V showed greater
noise reduction (30%–65%) than ASIR (25%–55%) both independent of dose,
where noise reduction with VEO was maximal (67%) at the lowest dose.
Conclusions: While VEO had the best physical performance for all inves-
tigated parameters, ASIRV represents a good solution to further reduce noise
while maintaining faster reconstruction time and image texture.
B.254
RADIOLOGIC IMAGING OF THE NEWBORN INSIDE THE INCUBATOR. PART
2: RADIATION DOSE AND IMAGE QUALITY
V. Del Rio L. Satta V. Fanti a Department of Physics, University of Cagliari,
Cagliari, Italy; b Medical Physics Unit, AOU, University of Cagliari, Cagliari, Italy
Introduction: Newborn babies in the Neonatal Intensive Care Unit (NICU),
especially those born before 37 weeks of gestation, often require many ra-
diological examinations during their first weeks of life. Since the risk of
cancer induction by exposure is higher for children than adults, it is crucial
to keep the exposure as low as reasonably achievable (ALARA), while main-
taining a satisfactory quality of the image.
Materials and Methods: In this work, conducted at the NICU of AOU in
Cagliari, an optimization study on radiation dose and image quality is per-
formed on three incubators using a test object TOR (CDR) and a neonatal
chest phantom (GAMMEX mod.610). In a previous study, attenuation values
of the components for the above-mentioned incubators were computed.
Using the TOR, low and high contrast sensitivity and spatial resolution are
calculated. Radiographs of the phantom are evaluated by a radiologist, on
the basis of anatomical features visibility, noise and contrast, using a five-
grade scale. Moreover, pathologies simulated with the phantom are
diagnosed by the radiologist. Indicators of diagnostic performance such as
sensitivity, specificity and odds ratio are evaluated.
Incident air Kerma on the phantom (Ka,i)ph and on the incubators plate
(Ka,i)p and Entrance Surface Dose (ESD) are calculated for different X-ray
exposure parameters and related to the corresponding image quality.
Results and Conclusions: Image quality, Ka,i and ESD are calculated and
compared for the three incubators under analyses. The different attenua-
tion features of the incubators have a significant influence on the above-
mentioned values. Finally, exposure values and incubators configurations
for optimizing the images quality and radiation dose are proposed.
B.255
RADIOLOGIC IMAGING OF THE NEWBORN INSIDE THE INCUBATOR. PART
3: RISK ESTIMATION
V. Del Rio L. Satta V. Fanti a Department of Physics, University of Cagliari,
Cagliari, Italy; b Medical Physics Unit, AOU, University of Cagliari, Cagliari, Italy
Introduction: Radiation risk strongly depends on the age at which expo-
sure occurs; therefore, newborn and especially prematurely born babies
are at highest risk for radiation-induced malignancies: risk of cancer in-
duction is believed to be 2–3 times higher than that of the average
population.
Materials and Methods: In this work, cancer risk resulting from an expo-
sure to ionising radiation is estimated using PCXMC 2.0, based on Monte
Carlo simulation. For each of three incubators used at the AOU of Cagliari,
organ doses and the effective dose received by the neonatal chest phantom
(GAMMEX mod.610) are computed, in order to calculate REID (Risk of
Exposure-Induced Death) and LLE (Loss of Life Expectancy) for female and
male newborn. A model for representing neonatal chest phantom is defined
in PCXMC; anatomic parameters, imaging geometry, beam conditions, ex-
posure field, and incident air Kerma on the phantom (Ka,i)ph values
(computed in a previous study) are configured as inputs.
Moreover, diagnostic and exposure data (projection, source-to-image re-
ceptor distance, kV, mAs) of radiographs on 113 newborn (64 males and
49 females) have been collected for 8 months. Radiation risk (REID and
LLE) for 4 newborn hospitalised is evaluated, relative to one or more
exams.
Results and Conclusions: As expected, for all the incubators REID in-
creases with Ka,i; the values for the female newborn resulted much higher
than the one for the male newborn. Moreover, REID increases with the
number of radiographs performed. The same behaviour and results are ob-
served for LLE.
Exposure values and incubators configurations, proposed in a previous work
for optimising images quality and radiation dose, also allow to minimise
the radiation risk.
Incubator features, such as attenuation and Focus to Skin Distance, have
an impact not only on the image quality and the radiation dose but even
on the cancer risk.
B.256
PRELIMINARY EVALUATION OF THE ABSORBED FETAL DOSE ASSOCIATED
WITH PRE-DELIVERY UTERINE ARTERIES EMBOLIZATION
M. Di Pasquale *. A.O.R.N. A. Cardarelli, Napoli, Italy
Introduction: In patients with diagnosed placental anomalies at high risk
for peri-post-partum hemorrhage, the pre-delivery embolization of uterine
arteries immediately before cesarean were performed in order to reduce
the blood loss and the subsequent blood units transfusions, and to avoid
hysterectomies. In this study, preliminary optimization of this radiologi-
cal procedure to achieve successful intervention with a fetus dose as low
as reasonably achievable is described.
Methods and Materials: From November 2012 to October 2015 a sample
of 65 pregnant patients were registered and underwent the treatment. All
the procedures have been performed in the gynecological operating room
with the use of a mobile C-arm angiograph (OEC 9800 Plus GE) and the
exposure parameters was recorded. The key points for optimize the pro-
cedural setting on this angiograph system are the following: use of
continuous fluoroscopy, no enlargement of the field of view, use of half-
dose filter, postero-anterior projection without tube tilting. In order to
evaluate the radiation absorbed of the fetus during the procedure, we cal-
culated the dose received by the uterus with the use of the PCXMC 2.0
program, adopting a Back Scattering Factor of 1.35 and measuring the En-
trance Surface Dose (ESD) by means of five thermo luminescent dosimeter
(TLD) positioned on the back of the patient in correspondence to the area
of X-ray beam incidence. As precaution, the highest ESD in each patient
was considered.
Results and Conclusions: The radiation doses received by the 65 uterus/
fetus range from 7,72–72,27 mGy, with an average of 30,43 mGy,
corresponding to an ESD ranges from 27,8–300,0 mGy with an average of
105,5 mGy. These values are in agreement with a negligible risk of causing
radiation induced hereditary effect and not result in any deterministic effects.
The study is going on and additional work is needed in order to under-
stand the impact of pulsed fluoroscopy use on different angiograph
systems.
B.257
ANALYSIS OF DOSIMETRIC DATA FROM CT EXAMINATION COLLECTED
WITH RDIM SYSTEM, TERRITORIAL AREA OF RAVENNA, AUSL DELLA
ROMAGNA
S. Farnedi N. Scrittori F. Ansaloni a Medical Physics, Ravenna, Italy;
b Diagnostic Imaging Department, Ravenna, Italy
Introduction: This study analyzes dosimetric data extracted over a period
of one year from 4 MSCT scanners in use in the Diagnostic Department of
AUSL della Romagna, area of Ravenna. Dosimetric data were evaluated for
all the exams and compared to recently published values
Materials and Methods: Data were retrieved through MPPS connection
using a Radiation Dose Index Monitoring (RDIM) system (Gray Detector soft-
ware, ELCO) directly integrated in the RIS and used for a web-based
registration of dosimetric data in the Radiology Department.
e76 Abstracts/Physica Medica 32 (2016) e71–e96