ThO₂–PuO₂ mixed oxide (MOX) experimental fuel pins have been fabricated at Bhabha Atomic Research Centre, for irradiation experiments as a part of an advanced fuel development programme. During the quality control of fuel pellets,the homogeneous distribution of the :ssile plutonium in them has been ascertained using alpha autoradiography and gamma autoradiography techniques. The quantitative estimation of the plutonium-rich regions of the pellets has been carried out by optical microdensitometry and digital image analysis. This paper discusses the implementation of the techniques and presents a few typical results.