RADIOACTIVE CEMENT OF PMMA an‎d HAP-Sm-153, Ho-166, o‎r RE-188 FOR BONE METASTASIS TREATMENT

Polymethylmetacrylte (PMMA) is used in the fields of den- tistry and biomedicine as a constituent of bone cements. Hydroxyapatite (HAp) is a bioceramic produced naturally in the bones. PMMA and HAp are fundamental constituents in the preparation of bone cements. Bisphosphonates have also been used as radiopharmaceutical in dental implants and nuclear medicine, or as palliative systemic treatment for pain reduction in bone metastasis. Vertebroplasty and kyphoplasty are bone cement-based techniques used in orthopedics, being minimally invasive procedures with low risks of infections, applied in osteoporosis and high-impact fractures. Recently, Núcleo de Radiações Ionizantes da Universidade Federal de Minas Gerais proposed a synthetic composite of M-HAp with a metallic nuclide M. After irradiation, M-HAp was added to PMMA, compounding a radioactive bone cement that can recover bone body stabilization, pasting microfractures and recomposing the anatomy and functionality of the affected parts by the compression of bone metastases, with possible pain reduction through quick radiation-induced decompres- sion. Computational dosimetric models, and the synthesis and characterization of bioceramics that incorporate Re-188, Ho-166, or Sm-153 have demonstrated the benefits of these biometrics as promising alternative therapies, mainly from their ability to maintain the ionization in the bone structure, thereby sparing the spinal cord. This article presents a review on this topic. Level of Evidence V, Expert Opinion