- Treatment of pigmented villonodular synovitis of the knee with yttrium-90 silicate: prospective evaluations by arthroscopy, histology, and 99mTc pertechnetate uptake measurements. Franssen, M.J., Boerbooms, A.M., Karthaus, R.P., Buijs, W.C., van de Putte, L.B. Ann. Rheum. Dis. (1989)