Dynamic heart-in-thorax phantom for functional SPECT

The authors have designed and built a dynamic heart-in-thorax phantom to be used as the primary tool for experimental verification of a quantitative dynamic functional imaging method they are developing for standard rotating single photon emission computed tomography (SPECT) cameras. The phantom consists of two independent parts (i) a dynamic heart model which allows up to two "defects" to be mounted inside it and, (ii) a non-uniform thorax model with lungs and spinal cord. The principle behind the design of the phantom is the fact that the washout of a tracer by dilution is governed by a linear first order equation, the same type of equation as is used to model time-activity distribution in myocardial viability studies. Tests of the dynamic performance of the phantom using the planar scanning mode have confirmed the validity of these assumptions. Also the preliminary results obtained from dynamic data acquired using a simplified version of the phantom in SPECT mode show that the values of characteristic times could be experimentally determined and that these values agreed well with the values preset on the phantom. The authors consider that the phantom is ready for use in the development of the dynamic SPECT method.