Presents the results of an investigation into the feasibility of producing models of human anatomy by linking MRI and stereolithography. Begins by describing the requirements for developing a link between the two technologies together with the major problems that this involves. Describes the processes undertaken to enable the creation of a model of a human brain. The model showed excellent anatomical details and demonstrated that the technique of linking MRI and stereolithography is entirely feasible. However, the preparatory work required prior to building the model showed that there are many difficulties associated with transferring and processing the imaging data. Recommendations are made as to how this technique needs to evolve.

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The paper is an extension of a previous one and discusses the distribution of current in a conductor which has a cross-section in the form of a symmetrical trapezium and is placed in a slot with a narrow opening. An approximate solution is obtained by assuming that the upper and lower surfaces of the conductor are defined by concentric cylinders. It is found that the current density at any point may be expressed as an infinite series of Bessel functions, each term involving an arbitrary constant which is determinable by reference to the assumed boundary conditions. From this result, the complex impedance per unit length of the conductor is determined and hence also the effective resistance and the internal reactance.List of principal symbols / = total current in conductor, A J -current density, A/m 2 a = conductivity of conductor, i Q -' m " 1 /A = permeability H = magnetic field strength, A/m R d = d.c. resistance per unit length of conductor, D R e = a.c. resistance per unit length of conductor, Q. X e = internal reactance per unit length of conductor, Q. OJ = 2?r x frequency r, 6 = polar co-ordinates R { , R 2 , 0\, 0 2 -slot parameters a =(uaco) l l 2 , m -1 2i X = 0 2 l0 l n -harmonic number y = v o> w v> v v = parameters defined by eqns. 32, 33, 38 and 39 ber, bei, ker, kei = real and imaginary parts of Bessel functions of a complex argument (defined in Reference 4) v is, in general, nonintegral