Devices and methods for optically scanning an in-vivo lumen, and for determining contact between an in-vivo device and an in-vivo lumen wall. The device may include an elongated housing having a cylindrical portion. At least one illuminating body may provide illumination at the circumference of the cylindrical portion, and at least one light sensor may sense light that penetrated and was scattered from the tissue of the in vivo lumen. The device may include a barrier for preventing direct illumination from the illuminating body from reaching the light sensor and for decreasing the amount of direct light reflection from the outer surface of the in vivo lumen onto the light sensor.