Performance evaluation of a newly developed high‐resolution, dual‐head animal SPECT system based on the NEMA NU1–2007 standard

Abstract

Small‐animal single‐photon emission computed tomography (SPECT) system plays an important role in the field of drug development and investigation of potential drugs in the preclinical phase. The small‐animal High‐Resolution SPECT (HiReSPECT) scanner has been recently designed and developed based on compact and high‐resolution detectors. The detectors are based on a high‐resolution parallel hole collimator, a cesium iodide (sodium‐activated) pixelated crystal array and two H8500 position‐sensitive photomultiplier tubes. In this system, a full set of data corrections such as energy, linearity, and uniformity, together with resolution recovery option in reconstruction algorithms, are available. In this study, we assessed the performance of the system based on NEMA‐NU1–2007 standards for pixelated detector cameras. Characterization of the HiReSPECT was performed by measurement of the physical parameters including planar and tomographic performance. The planar performance of the system was characterized with flood‐field phantom for energy resolution and uniformity. Spatial resolution and sensitivity were evaluated as functions of distance with capillary tube and cylindrical source, respectively. Tomographic spatial resolution was characterized as a function of radius of rotation (ROR). A dedicated hot rod phantom and image quality phantom was used for the evaluation of overall tomographic quality of the HiReSPECT. The results showed that the planar spatial resolution was ~1.6.15emmm and ~.15em2.3.15emmm in terms of full‐width at half‐maximum (FWHM) along short‐ and long‐axis dimensions, respectively, when the source was placed on the detector surface. The integral uniformity of the system after uniformity correction was 1.7% and 1.2% in useful field of view (UFOV) and central field of view (CFOV), respectively. System sensitivity on the collimator surface was 1.31.15emcps/μCi and didn't vary significantly with distance. Mean tomographic spatial resolution was measured ∼1.7 mm FWHM at the radius of rotation of 25 mm with dual‐head configuration.The measured performance demonstrated that the HiReSPECT scanner has acceptable image quality and, hence, is well suited for preclinical molecular imaging research.PACS number: 87.57.U

Design and development of a dedicated portable gamma camera system for intra-operative imaging

“…As expected for parallel-hole collimation, a small decrease is observed when distance is increased [30,31]. The sensitivity decreased sharply when the distance exceeds the size of detector FOV.…”

Pinhole X-ray fluorescence imaging of gadolinium and gold nanoparticles using polychromatic X-rays: a Monte Carlo study

“…69,70 Since our system was modeled by benchmarking the pinhole SPECT system, which detects much higher energy photons than K-shell XRF photons, [52][53][54][55][56] further investigation in optimizing the system design -such as collimator design, X-ray filter, and tube potential -is needed to reduce the dose level and improve the image quality. In addition, if the aforementioned 2D pixelated detectors with high-energy resolution are commercially available, discrete XRF peaks can be analytically separated from the background photons.…”

“…38 The model was benchmarked against the design and the dimension of the pinhole, as well as the type and the pixel size of the detector commonly used in preclinical pinhole SPECT. [52][53][54][55][56] A cylindrical water phantom in the middle, as shown in Figure 1A, had a diameter of 5 cm and a height of 5 cm each. Four cylindrical water columns, 1 cm in diameter and 3 cm in height, containing GdNPs or AuNPs of different concentrations (0.01 wt%, 0.03 wt%, 0.06 wt%, and 0.09 wt%) were placed in the water phantom, as shown in Figure 1B.…”

Implementation of absolute quantification in small‐animal SPECT imaging: Phantom and animal studies

“…The aim of this study is to develop and evaluate an approach to quantitative SPECT imaging using an iterative reconstruction method along with corrections. Specifically, we aim to improve the quantification accuracy in our dedicated animal SPECT system called HiReSPECT . We have developed a calibration method to determine the activity concentration in MBq/ml, via a system image matrix.…”