To rapidly determine the efficacy of genetic and pharmaceutical therapies for CF we have developed MCT monitoring methods in live anaesthetised normal and CFTR-null mice to measure the transport rate and behaviour of individual deposited 10-30 μm diameter high refractive index (HRI) glass bead marker particles using propagation-based synchrotron phase contrast X-ray imaging (PCXI) [4]. The gene discussed is CFTR; the disease is cystic fibrosis.