A fail safe concealment mechanism for a radiation imaging capsule, including, a collimator having a first area that blocks radiation and an second area that releases radiation, a radiation source that is initially positioned inside the collimator in the area that blocks radiation, a linear mechanism that moves the radiation source inside the collimator to the area that releases radiation when power is provided to the mechanism and automatically returns the radiation source to the area that blocks radiation when power is not provided to the mechanism.