Proof of Exact Computing Formula for Lambda Tomography

This paper re-proves the theorem for exact computing formula of lambda tomography in reference 6.The lambda tomography is a class of technology reconstructing from few scanning data,which can reduce the radiation dose of the scanned objects and improve the speed of image reconstruction.Reference 6 proved an exact reconstruction formula of lambda tomography in the case of fan beam scanning geometry.This paper provides an alternative simplified proof of the theorem in 6.