Feasibility study of multi Laue lens based SPECT with a dedicated 3D reconstruction algorithm using Monte Carlo simulations

The development of in-vivo imaging techniques has significantly advanced biomedical science and cancer diagnosis, yet their limited spatial resolution constrains their utility in small-animal studies and early-stage tumour detection. This study introduces a novel SPECT system employing X-rays and gamma-rays focusing optics-traditionally used in astronomy-to enhance spatial resolution in small object imaging at sub-millimetre scales without compromising sensitivity. Current SPECT imaging techniques rely on absorptive collimation, which creates a trade-off between sensitivity and resolution, often limiting spatial resolution and hindering the examination of various biomedical research areas, thereby restricting the accurate identification of small lesions. Our innovative design utilizes an array of Laue lenses, which can focus gamma rays without the drawbacks of traditional collimators, thereby achieving ultra-high spatial resolution. This approach is motivated by the need for improved imaging capabilities that allow for the detection of subtle physiological changes and tumour evolution in transgenic models, which are critical for advancing personalized medicine and significantly impacting early-stage tumour detection. A custom Monte Carlo simulation models the system's spatial resolution and sensitivity, supported by a tailored 3D reconstruction algorithm that complements the system's geometry. Findings reveal that our proposed system can achieve a spatial resolution of 0.1 mm full width at half maximum (FWHM) and a sensitivity of 1,670 cps/µCi. This setup allows the discrimination of adjacent volumes as small as 0.113 nL, far surpassing the capabilities of existing SPECT systems, including the SIEMENS parallel LEHR and multi-pinhole (5-MWB-1.0) Inveon SPECT, which are limited to a 2 mm resolution due to inherent resolution-sensitivity trade-offs. The proposed design could revolutionize SPECT imaging, significantly impacting transgenic animal research and early-stage tumour detection with its sub-millimetre resolution, ultimately enabling more precise and effective diagnostic capabilities in preclinical studies.