Abstract
Background: the need for simultaneous
high-sensitivity and high-resolution breast SPECT imaging mandates
to design and optimize dedicated scanners. Therefore, this work aims
to design and optimize a novel breast-dedicated SPECT system with
multi-lofthole collimator.
Materials and Methods: in this research, a novel
breast-dedicated scanner is designed and then optimized. The scanner
is equipped with a single full-ring multi-lofthole collimation long
with modular NaI(Tl) detectors. The step-and-shoot data acquisition
was considered with two steps. Then, an analytic optimization was
conducted to balance the existing sensitivity-resolution
tradeoff. To do so, several scanner geometries were
investigated. The optimal configuration maximized the system
sensitivity at a given system resolution. Furthermore, the scanner
was also modeled within the GATE simulator. Then, detector energy
resolution, septal penetration and scattering, and system
sensitivity were calculated. Analytic findings were also compared
with the simulated ones.
Results: the results showed that high sensitivity of about
2 cps/kBq can be obtained for a diameter of lofthole 3.05 mm with
a 75° opening angle. Results of GATE simulations showed
clinically acceptable performance of the system offering 9% energy
resolution for a point source. The septal penetration and scattering
were approximately 0.5% and 0.2%, respectively, for cylindrical
water phantom and tungsten as collimator material.
Conclusion: the designed SPECT scanner provides promising
results in terms of sensitivity and spatial resolution and therefore
outperforms the traditional multi-pinhole collimation by a much
higher sensitivity at a given system resolution.
Colloquium
: Quantum limits to the energy resolution of magnetic field sensors
