Quality control protocol for in vitro micro‐computed tomography

Abstract

SummaryThe aim of this work was to present and discuss a quality control protocol for in vitro micro-computed tomography (microCT), based on the adaptation of the quality control protocols for medical computed tomography. The importance of establishing a quality control protocol is related to the opportunity to identify problems on time comparing the microCT images acquired in different time points, and in this way to verify the performance of the device. The proposed quality control protocol was applied for a long-time monitoring period to verify the stability of the micro-tomographic system over time. The protocol proposed in this study was applied to the histomorphometric characterization of bone tissue, but it can be used on a wide range of in vitro microCT applications. Noise and uniformity tests, taken and adapted to micro-tomographic system by medical standard guidelines of quality control, were performed by the use of a water phantom. An accuracy test was designed and performed by the use of a morphometric calibrated phantom. All these tests were performed during a long-time monitoring period to control the stability of the system. Specific control charts and monitoring parameters for each test were used to represent the monthly measures collected during 20 months and an out of control condition was defined. The reference values (baseline), calculated to control the stability of micro-tomographic system over time, were calculated during acceptance/status test. During the period, no out of control conditions in noise, uniformity and accuracy tests were recorded. However, a changing condition was found in noise test, as showed by using statistical C (P < 0.01) and Kruskal-Wallis (P < 0.05) tests. In particular, a Wilcoxon rank sum test with Bonferroni correction (P < 0.0125) was applied in noise test to investigate which of the comparisons among first five acquisitions of year 2004 (group B.L.) and each group was significant

The Importance of Routine Quality Control For Reproducible Pulmonary Measurements By in Vivo Micro-CT

“…The data reported in this study were collected on speci c control charts and compared to baseline (BL) values, each de ned by upper and lower tolerance limits, as suggested by literature 25,31 . BL values were initially established for our Quantum GX micro-CT (PerkinElmer, Inc. Waltham, MA), acquiring ve consecutive scans of the QC phantoms 31,32 . For each monitored parameter, the BL and tolerance width were calculated, respectively:…”

“…Additionally, in-house-developed devices and protocols 15,30,31 are not easily applicable to other imaging centres.…”

Traceable micro‐CT scaling accuracy phantom for applications requiring exact measurement of distances or volumes

“…Two quality assurance phantoms have been previously developed to directly measure the scaling accuracy of micro-CT images. 4,11,12 However, neither of these phantoms provided a traceable method to calibrate micro-CT image voxel sizes. In this paper, a quality assurance phantom qualified to a traceable standard is presented along with an automated image processing algorithm to characterize the scaling accuracy of micro-CT scanners.…”

MicroCT: An Essential Tool in Bone Metastasis Research

“…These resolutions down to 100 nm are called nanoCT and may allow for imaging on the cellular level including the canal network, osteocyte lacunae, and even single cells. In addition, these machines can be used in the visualization of microfractures (Muller, 2009;Stock, 2009). A recent study used nanoCT to examine osteocyte lacunae and the canalicular network (Dierolf et al, 2010).…”

“…When performing repeated microCT scanning, several factors must be optimized to minimize differences between scans. Repeated image acquisition requires special considerations including positioning, scanning medium (for ex vivo), image resolution, and uniform regions of interest (Stock, 2009). During processing, samples are filtered, segmented, registered, and uniform regions of interest are applied to create masks for differentiating between cortical and trabecular bone.…”