Monte Carlo simulation of a silicon
strip detector response for
angiographic applications.
First approach.
C. Ceballosa, G. Baldazzib, D. Bollinib, A.E.Cabal Rodrígueza, W. Dabrowskic,
A.Días Garcíaa, M. Gambaccinid, P. Giubellinoe, M. Gombiab, P. Grybosc,
M.Idzikc,e, A. Marzari-Chiesaf, L.M. Montañog, F. Prinoh, L. Ramelloh, M.
Sittah, K. Swientekc, A. Taibid, A. Tuffanellid, R. Wheadone, P. Wiacekc
a
b
c
d
e
f
g
h
CEADEN, Havana, Cuba;
Dipartimento di Fisica dell’ Università di Bologna and INFN, Bologna, Italy;
Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Cracow, Poland;
Dipartamneto di Fisica dell’ Università di Ferrara and INFN, Ferrara, Italy;
INFN, Torino, Italy;
Dipartimento di Fisica dell’ Università di Torino and INFN, Torino, Italy;
CINVESTAV, Mexico City, Mexico,
Dipartimento di Scienze e Tecnologie Avanzate dell’ Università
del Piemonte Orientale and INFN, Alessandria, Italy
ABSTRACT
First results of Monte Carlo simulation by MCNP transport code of an experimental facility at
Bologna S. Orsola hospital for studying the possible application of a X-Ray detection system
based on a silicon strip detector on a dual energy angiography.
The quasi-monochromatic X-ray beam with the detector in the edge-on configuration has been
used to acquire images of a test object at two different energies (namely 31 and 35 keV) suitable for
the K-edge subtraction angiography application.
As a test object a Plexiglas step wedge phantom was used. It was 40 mm high and 50 mm wide
and with a thickness ranging from 10 mm to 40 mm with three 2mm Aluminum layers on it . Four
cylindrical cavities, having a 1 mm diameter, have been drilled and filled, with iodated contrast
medium, whose concentration varied from 370 mg/ml to 92 mg/ml.
Both the profiles obtained from measurements and the images generated with them where
reproduced by computer simulation on a first approach to use this technique as an evaluation tool
for future developments on the experimental setup
EXPERIMENTAL SETUP
MCNP
Simulated
Geometry
DEAD
ZONE
STRIPS
Aluminium Layer
PMMA
1 mm Iodine Filled Tube
Detector characteristics
Strip length
10 mm
Thickness
300 m
Dead region (edge – on config.)
765 m
Strip pitch
100 m
Strip width
80 m
400
Photo of the upper-left detector’s corner Channels
Conc(I) = 370 mg/ml
E = 31.5 KeV
Counts / Max.Counts
1,0
Conc(I) = 370 mg/ml
0,8
0,6
E=31.5 KeV
0,4
0,2
Measurement
Simulation
0,0
0
50
100
150
200
250
300
350
Strip Number
Image obtained from measurements
Image obtained from simulation
Counts / Max.Counts
1,0
Conc(I) = 370 mg/ml
E = 35.5 KeV
Conc(I) = 370 mg/ml
0,8
0,6
E=35.5 KeV
0,4
0,2
Measurement
Simulation
0,0
0
50
100
150
200
250
300
350
Strip Number
Image obtained from measurements
Image obtained from simulation
ln[count(E=35.5Kev)] - ln[count(E=31.5Kev)]
Measurement
Simulation
Conc(I) = 370 mg/ml
0,2
Conc(I) = 370 mg/ml
0,0
-0,2
K-edge subtraction image:
-0,4
-0,6
ln(image35.5) - ln(image31.5)
-0,8
-1,0
0
50
100
150
200
250
300
350
Strip Number
Image obtained from measurements
Image obtained from simulation
ln[count(E=35.5Kev)] - ln[count(E=31.5Kev)]
Conc(I) = 185 mg/ml
0,2
Measurement
Simulation
0,1
Conc(I) = 185 mg/ml
0,0
-0,1
K-edge subtraction image:
-0,2
-0,3
ln(image35.5) - ln(image31.5)
-0,4
-0,5
-0,6
0
50
100
150
200
250
300
350
Strip Number
Image obtained from measurements
Image obtained from simulation
ln[count(E=35.5Kev)] - ln[count(E=31.5Kev)]
Conc(I) = 92 mg/ml
0,2
Measurement
Simulation
Conc(I) = 92 mg/ml
0,1
0,0
K-edge subtraction image:
-0,1
ln(image35.5) - ln(image31.5)
-0,2
-0,3
-0,4
0
50
100
150
200
250
300
350
Strip Number
Image obtained from measurements
Image obtained from simulation