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HIGH RESOLUTION, HIGH
MOLECULAR IMAGING
CODED APERTURE
F. Cusanno, E. Cisbani, S. Colilli, R. Fratoni,
F. Santavenere, R. Accorsi, R. C. Lanza,
THE DETECTOR
W mask
NaI(Tl) scintillator
1 mm2 x 6 mm
Hamamatsu
H8500 PS-PMT
SENSITIVITY DETECTORS FOR
WITH RADIONUCLIDES:
OPTION
F. Garibaldi, F. Giuliani, M. Gricia, S. Lo Meo, M. Lucentini
S. Majewski, M. N. Cinti, R. Pani, R. Pellegrini
MURA 14 masks
High FoV,
1.1 mm pitch
High Resolution,
0.7 mm pitch
The detector is mounted for a mask-scintillator distance of b=44
mm, different support are used to perform measurements with
different source-mask distance a. The minimum source-mask
distance depends on a
Modified Uniformly Redundant Array (MURA).
The name comes from the property that all
separations between holes in the pattern occur a
constant number of times. The arrays are
generated with the same algorithm (A) used for
the URAs.
(Uniformly Redundant Array) but with the different that, G (decoding
array), can not be equal to A because the autocorrelation is not a
delta function. Mask (A, G) and Anti-Mask (1-A, -G), have the same
ideal correlation properties. First and second order artifacts are
seen to depend only on G, so adding the two images, coming from
Mask and Anti-Mask the Near-Field artifacts are deleted.
Detector
pixel size
determines
the DoF
b

b
m  1 mp 1
ap d  1   p m
a
a

mpm
m
g  a
 pm
b
m 1
FoV  n g
b
a
pd
a
1
pm
g
CA Spatial Resolution
pm
Mask pixel size
pd
Pixel Dimension
n # of apertures
DoF
m Magnification factor
( a = 40.1 mm )
Source-Background
Uptake ratio 6:1
12 x 12 mm² Tumor
SNR =119  4
Source-Background
Uptake ratio 6:1
8 x 8 mm² Tumor
SNR = 90  3
Source-Background
Uptake ratio 6:1
5 x 5 mm² Tumor
SNR = 74  3
Source-Background
Uptake ratio 12:1
12 x 12 mm² Tumor
SNR =135  4
Source-Background
Uptake ratio 12:1
8 x 8 mm² Tumor
SNR =105  3
Source-Background
Uptake ratio 12:1
5 x 5 mm² Tumor
SNR = 89  3
Source-Background
Uptake ratio 6:1
Source-Background
Uptake ratio 12:1
3 x 3 mm² Tumor
3 x 3 mm² Tumor
SNR = 47  2
SNR = 63  2
( a = 40.1 mm )
Source-Background
Uptake ratio 6:1
12 x 12 mm² Tumor
Source-Background
Uptake ratio 12:1
12 x 12 mm² Tumor
SNR =135  4
Source-Background
Uptake ratio 6:1
8 x 8 mm² Tumor
Source-Background
Uptake ratio 12:1
8 x 8 mm² Tumor
SNR =105  3
Source-Background
Uptake ratio 6:1
5 x 5 mm² Tumor
Source-Background
Uptake ratio 12:1
5 x 5 mm² Tumor
SNR = 89  3
Source-Background
Uptake ratio 6:1
Source-Background
Uptake ratio 12:1
3 x 3 mm² Tumor
3 x 3 mm² Tumor
SNR = 63  2
Source-Background
Uptake ratio 6:1
12 x 12 mm² Tumor
Source-Background
Uptake ratio 6:1
8 x 8 mm² Tumor
Source-Background
Uptake ratio 6:1
5 x 5 mm² Tumor
( a = 40.1 mm )
57Co
point source
FWHM = 0.93 mm
Sensitivity=850 cps /MBq
40 cps/MBq with pinhole
12 x 12 mm² Tunor, 12:1 Uptake ratio (a = 54.7 mm)
Background thickness = expected DoF (36.4 mm)
a = 40.1 mm
SNR = 65  3
a = 54.7 mm
SNR = 100  4
ARTEFACTS DUE TO 3D SOURCE
a = 76.5 mm
SNR = 51  3
High-FoV Mask, 8 mm source at 38 mm distance
FoV=25 mm
FoV=35 mm
FoV=30 mm
FoV=40 mm
High-Resolution Mask, 8 mm source at 20 mm distance
FoV=14 mm
FoV=16 mm
FoV=18 mm
FoV=20 mm
CONCLUSION
Coded Apertures allows 3D object imaging like hot spot
Bigger detector, 100 x 100 mm2 ,2 x 2 array of H8500 or
up to 1024 channels
AND OUTLOOK
in a 3D background with lower uptake, 12:1 in our studies
H9500 PS-PMTs, ASICS electronics by IDEAS reading-out
The new detector could be equipped with
Hamamatsu H8500 PS-PMT as well as
with H9500 PS-PMTs, so a new
electronics will be used, based on FrontEnd-Card 5053 by IDEAS