- The PLACORHEN study: a double-blind, placebo-controlled, randomized radionuclide study with (186)Re-etidronate in hormone-resistant prostate cancer patients with painful bone metastases. Placebo Controlled Rhenium Study. Han, S.H., de Klerk, J.M., Tan, S., van het Schip, A.D., Derksen, B.H., van Dijk, A., Kruitwagen, C.L., Blijham, G.H., van Rijk, P.P., Zonnenberg, B.A. J. Nucl. Med. (2002)