Abstract: A synthetic calcium phosphate-based biomedical material comprising gadolinium. The material may comprises a compound having the general chemical formula: Ca10?yGdy(PO4)6?x(SiO4)x(OH)2?x+y where 0<x<1.3 and 0<y<1.3.

Abstract: The present invention relates to drilling apparatus comprising a drill-bit (1) capable of rotary and high frequency oscillatory loading; and control means for controlling applied rotational and/or oscillatory loading of the drill-bit, the control means having adjustment means for varying the applied rotational and/or oscillatory loading, said adjustment means being responsive to conditions of the material through which the drill is passing. The control means is in use provided on the apparatus in a downhole location and includes sensors for taking downhole measurements of material characteristics, whereby the apparatus is operable downhole under closed loop real-time control. The apparatus can determine appropriate loading parameters for the drill-bit in order to achieve and maintain resonance between the drill-bit and the drilled material in contact therewith.