Due to their numerous advantages, Slurry Bubble Column Reactors (SBCR) are gaining wide importance in the petroleum, petrochemical, chemical, and biochemical industries. Most previous literature studies on the fluid dynamics and the phase holdup distribution in SBCR are limited to low superficial gas velocity, low solids loading, and the atmospheric pressure. Moreover, the presence of a solids phase poses difficulties in probe measurement techniques such as pitot tube and optical probe and see through measurement techniques such as particle image velocimetry (PIV), Laser Doppler Velocimetry (LDV). Single source-γ-ray Computed Tomography (CT) has been used to measure cross-sectional phase holdup distribution in two-phase systems. In the present study, a new methodology has been developed that combines a single source CT with overall gas holdup measurement, along with valid assumptions, to measure the cross-sectional holdup distribution of the three phases in a slurry bubble column. The implementation of developed methodology has been demonstrated using air-water-glass beads (150 μ m) at selected conditions of superficial gas velocity and operating pressure.