To celebrate the beginning of spring, this scan of the month features the one tool every gardener needs to have: a garden trowel! It is an essential tool for a variety of tasks such as breaking up the soil on the surface, incorporating fertilizers, digging small holes, transplanting, planting, repotting…
Recently a neuroscience researcher (Dr. Christopher Lowry) has demonstrated that the bacterium Mycobacterium vaccae, present in the soil, can have a positive effect on human mental states. It seems that this bacterium reduces anxiety and stimulates the production of serotonin (the happiness hormone) in the medial prefrontal cortex. It works like an antidepressant. All you have to do is some gardening…and enjoy the fresh air!
The scans and segmentation were performed by Onur Cildir and Xinyang Hao (Applications engineers X-ray & CT). X-ray CT enables us to visualize the internal structure of the trowel, non-destructively.
A CT reconstruction of a sample with two materials of significantly different density, causes artefacts. These artefacts are reduced by Dual.Material CT, a new reconstruction software product that reduces artefacts and improves the data quality from much shorter scan times.
This trowel is made from metal and plastic, therefore, the scans were corrected using Nikon’s Dual.Material CT reconstruction technique to compensate for beam hardening effects coming from the metal (as shown below).
These X-ray CT scans were acquired using Nikon’s Helical (X.Tend) and circular acquisition algorithm at a combined X-ray power between 60 and 210 W and voxel resolutions between 30 and 70 µm, using a Nikon XTH 225 ST 2x. This system comes equipped with up to three different Nikon microfocus X-ray sources: a 180 kV, 20 W transmission target, a 225 kV, 225 W reflection target and a 225 kV, 225 W rotating target. These scans were performed using the 225 kV reflection target and rotating target option coupled with a Varex XRD 4343CT flat panel detector. For these scans the detector acquired between 2000 and 5000 projections (individual radiographs) at an exposure time between 125 and 708 ms, resulting in a total scan time between 5 minutes and 1 hour.