Superficial Skin Temperature Sensor System

Transcription

1 Superficial Skin Temperature Sensor System Date: 26/09/2018 Author: Stefano Perticaroli (CEO) Radio Analog Micro Electronics srl Location: EuroBioHighTech Trieste, Italy Unlocking capabilities in innovation

2 Who we are RAME srl is an Italian engineering company active in microelectronics and, more in general, in electronics design. The company has some specific expertises in RF & MW, in Power Management and in EM-based sensor development and integration. Website: ramesrl.it Architectural Level Design and development of RF systems in integrated technologies (CMOS, SiGe,...) TLC protocol development IC architecture planning and optimization Analysis and engineering Device of active devices for RF Level applications Solid state analysis based on TCAD EM-based design and optimization of structure for Passive Structures remote sensing EM Full Wave analysis 2/10

3 Introducing the application context Skin temperature is a fundamental indicator of skin vitality. Many papers documented the correlation between skin temperature variations and skin diseases as well as diseases related to deep vascular flow in legs or arms. In example temperature gradients in skin areas are observed in patients with vascular diseases, showing anomalous flow rate in affected regions. Some of the bibliographic references we found... [1] Winsor T., Skin temperatures in peripheral vascular disease: a description of the thermistor thermometer JAMA. 1954;154(17): [2] Bagavathiappan S., et al., Investigation of peripheral vascular disorders using thermal imaging, The British Journal of Diabetes & Vascular Diseases, Vol 8, Issue 2, pp First Published March 1, [3] Huang C.L., et al., The application of infrared thermography in evaluation of patients at high risk for lower extremity peripheral arterial disease, Journal of Vascular Surgery, Volume 54, Issue 4, 2011, Pages , ISSN , [4] Thiruvengadam, J., et al. B. (2014). Potential of thermal imaging as a tool for prediction of cardiovascular disease. Journal of Medical Physics / Association of Medical Physicists of India, 39(2), [5] Alfred Gatt, et al., Thermographic Patterns of the Upper and Lower Limbs: Baseline Data, International Journal of Vascular Medicine, vol. 2015, Article ID , 9 pages, and many other 3/10

4 The idea behind the a selective thermographic imager Descending from these considerations, an apparatus capable of detecting temperature in the form of an image closely related to surface would be a valid diagnosis instrument. Gradients in image and variations across subsequent images can be used to monitor temperature variations and vascular flows. Current methods for implementing thermographic imagers are based on 'irradiation' heat transfer, e.g. thermocameras. But they can only 'sense' heat sourced from a finite volume, averaging effective surface information with that one coming from deeper tissues. Vascular flow monitoring is instead mainly based on perfusion of fluids as Indocyanine and Fluorescein. These methods and techniques are very accurate even though they are invasive and cannot be applied in real-time operations. Selective sensing of temperature (and derived measurements) can be obtained through heat transfer via conduction. 4/10

5 Superficial Skin Temperature Sensor System Acquisition and Analog Processing Electronics Sensor Matrix Flexible support to be put in contact with skin Italian Patent application number filed on September Digital Post-processing and Visualization Interface Figure:SSTSS simplified block diagram. System is composed of a flexible two-dimensional matrix of sensors and a reading electronics board connected itself to a visualization front-end. The flexible matrix can be adapted to the human body in different areas. The sensing size is currently about 8cm X 16cm. 5/10

6 The proposed sensor capabilities Figure: sensor matrix on flexible support (back side). Sensor has a native resolution of 512 pixels with a density of 4 sensor per square cm. Temperature accuracy is around 1/100 of Celsius degree, after matrix calibration. The low thermal inertia of sensors allows measurement settling time in the range of a second. 6/10

7 The proposed system capabilities System is currently able to natively represent an image-like map of temperature with no post-processing. The acquisition time is lower than 40ms for all 512 sensors. The time needed for the temperature to settle depends on two parameters: - inertia due to heat capacity of sensor matrix (very low); - difference in temperature between sensor matrix and surface to be sensed (variable). In any case we tested the settling time by a thermodynamic point of view to be no longer than 1-2 seconds. The system needs to be calibrated against a temperature reference in order to provide accurate absolute measurements. The temperature reference has to be chosen in the neighborhood of the expected temperature range to be monitored. Due to the fast acquisition time a real-time sequence of images, composing a video, can be produced, adding the feature to detect flows direction and rates. Several post-processing are further available to calculate temperature gradients and to magnify the native 512 pixels resolution by means of adaptive graphic interpolations. 7/10

8 Preliminary results of testing Figure:SSTSS acquired thermographic image of right hand. Settling time: 0.87s; acquisition time 15ms. Statistical analysis on acquired data after 25 C deg calibration shows a consistent thermometric accuracy better than 1/100. 3σ deviation: ±0.01 C deg. Figure:SSTSS statistical analysis on acquired data for several sensor matrices (10 sensors matrices samples) 8/10

9 Clinical trials In order to develop models and define both operative procedure for applications in medical context as well as to assess a statistical analysis clinical trials are needed. Possibly in surgery trials we foresee: - evaluation of skin flap vitality used to reconstruct loss of substance (plastic surgery); - evaluation of lacerated and contused wounds (traumatology); - evaluation of deep burns on the skin vitality basis; - evaluation of vital tissue before of amputation (diabetic foot); - evaluation of vascularization in suture margins in pre, post and during surgery. Clinical trials will also give a feedback on how to adapt supporting material for sensor matrix or to adjust calibration procedure. 9/10

10 Development perspectives This project is looking for investors and/or partners who can support us in several activities: Additional development tailor sensor densities to specific applications; improve supporting materials and sensing elements; embed the sensor matrix into medicament and/or bandage. Medical Certification as medical equipment classification depending on applications and required class medical devices - 93/42/CE (MDD) medical devices in vitro - 98/79/CE (IVD) implantable medical devices - 90/385/CE The goal is a new medical instrument or diagnosis tool! 10/10