Proper lighting in rendering is essential for visualizing 3D objects, but most visualization software tools still employ simple lighting models. The advent of hardware-accelerated advanced lighting suggests that volume visualization can be truly usable for clinical work. Researchers studied how volume rendering incorporating global illumination impacted perception of bone surface features captured by x-ray computed-tomography scanners for clinical monitoring of rheumatoid arthritis patients. The results, evaluated by clinical researchers familiar with the disease and medical-image interpretation, indicate that interactive visualization with global illumination helped the researchers derive more accurate interpretations of the image data. With clinical needs and the recent advancement of volume visualization technology, this study is timely and points the way for further research.