Investigation of optical detection strategies for transabdominal fetal heart rate detection using three-layered tissue model and Monte Carlo simulation

摘要

In this paper, the Monte Carlo technique is used to determine the optical detection strategies in three-layered (maternal, amniotic fluid and fetal) tissue model. This model is utilized to estimate the transabdominal optical power and optimum source—detector (S—D) separation. Results based on the launching of 2 million photons with 1 mW optical power showed that the expected optical 10~(-10) W/cm~2 power output is in the range of 10~(-6)-10~(-10)W/cm~2 depending on S—D separation. Considering the limit of the signal processing methods (such as adaptive noise cancelling) and the use of silicon photodetector, an S—D separation of 4 cm has been selected as a practical compromise between signal level and percentage of optical power (70%) coming from the fetal layer. Based on these findings,transabdominal fetal heart rate detection system using NIR and adaptive filtering can be designed and developed.