Design and Implementation of a Wireless Capsule Suitable for Autofluorescence Intensity Detection in Biological Tissues

作者：Al Rawhani Mohammed A^*; Chitnis Danial; Beeley James; Collins Steve; Cumming David R S

来源：IEEE Transactions on Biomedical Engineering, 2013, 60(1): 55-62.

DOI：10.1109/TBME.2012.2222641

• Autofluorescence (AF) endoscopy
• endoscopic capsule
• noninvasive diagnosis
• single-photon avalanche diode detector (SPAD)

We report on the design, fabrication, testing, and packaging of a miniaturized system capable of detecting autofluorescence (AF) from mammalian intestinal tissue. The system comprises an application-specific integrated circuit (ASIC), light-emitting diode, optical filters, control unit, and radio transmitter. The ASIC contains a high-voltage charge pump and single-photon avalanche diode detector (SPAD). The charge pump biases the SPAD above its breakdown voltage to operate in Geiger mode. The SPAD offers a photon detection efficiency of 37% at 520 nm, which corresponds to the AF emission peak of the principle human intestinal fluorophore, flavin adenine dinucleotide. The ASIC was fabricated using a commercial triple-well high-voltage CMOS process. The complete device operates at 3 V and draws an average of 7.1 mA, enabling up to 23 h of continuous operation from two 165-mAh SR44 batteries.

• 出版日期2013-1