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Skin Res Technol. 2009 Feb;15(1):6-13. doi: 10.1111/j.1600-0846.2008.00330.x.

Cutaneous bioengineering instrumentation standardization: the Tissue Viability Imager.

Author information

1
Department of Biomedical Engineering, Linköping University, Linköping, Sweden. gerni@glocalnet.net

Abstract

BACKGROUND:

Tissue Viability Imaging (TiVi) is a new bioengineering technology intended for remote two-dimensional mapping of skin red blood cell concentration (RBC(conc)). Before use in the laboratory, work-site and dermatology clinic, critical performance parameters of this emerging technology require careful evaluation.

OBJECTIVE:

To assess short- and long-term stability, image uniformity, distance and image size dependence, ambient light and curvature influence in a production batch of Tissue Viability Imagers.

METHODS:

Four Tissue Viability Imagers from the same production batch were evaluated at two laboratories (one industrial and one dermatological) with respect to critical parameter performance.

RESULTS:

The average systematic drift in sensitivity over time was 0.27% and <1.02% for all four units tested. Difference in sensitivity between units was limited to 4.1% and was due to offset rather than gain deviation. Spatial variation in image uniformity was below 3.08% and 1.93% in the corners and centre of an individual image, respectively. This spatial variation could be further reduced to 0.25% and 0.13%, respectively by image normalization. Ambient light from a 40 W bulb or a 11 W fluorescent light source at a distance of 50-60 cm above the object, reduced the recorded values by about 10%, while the camera to object distance and image size had no detectable influence on sensitivity. Curved objects, such as human forearm, demonstrated an edge effect limited to below 10%.

CONCLUSION:

The critical TiVi performance parameters evaluated proved stable in relation to expected variations in skin RBC(conc) over time. Calibration by way of a two-point method may reduce differences in sensitivity between instruments to further facilitate inter-laboratory comparison of results.

[Indexed for MEDLINE]

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