IR sensor with high sensitivity

[acks]

i am using an IR sensor to measure the blood flow in the finger, by placing the finger between the sensor and IR LED(transmitter). I need an IR sensor sensitive enough to detect the change in intensity of IR radiation caused by blood flow.
Please suggest which sensor can i use?

 

[ckshivaram]

you dont use IR to do this work... in a simple way you use a LDR to do this.

---------- Post added at 16:14 ---------- Previous post was at 16:13 ----------

Schematics pic Microcontrollers

 

[acks]

This is the circuit we have built.. so could you suggest how to add LDR sensor to it ? this is our circuit -
We require the sensor to detect the light with IR wavelength, will LDR solve this purpose ?