Dynamic heart-in-thorax phantom for functional SPECT

We have designed and built a dynamic heart-in-thorax as a primary tool during the verification of the performance of the quantitative dynamic functional imaging method we are developing for standard rotating single photon emission computed tomography (SPECT) cameras. The phantom consists of two independent parts (i) a dynamic heart model with the possibility of mounting "defects" inside it and (ii) a non-uniform thorax model with lungs and spinal cord, and uses 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 in planar scanning mode have confirmed the validity of these assumptions. Also the preliminary results obtained 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. We consider that the phantom is ready for extensive use in studies into development of the dynamic SPECT method.