<p>Many cancer diagnosis and treatment modalities have been developed over time among which radioisotopes have been widely used. Recently with the application of magnetic nanoparticles a wide range of non-invasive diagnosis and treatment methods using magnetic techniques have attracted attention.</p><p>This Special Issue introduces a lymph node biopsy method with a magnetic probe for the treatment of cancer rapid immunostaining using magnetic nanoparticles in pathological diagnosis cancer imaging with MRI (magnetic resonance imaging)/MPI (magnetic particle imaging) magnetic hyperthermia for cancer treatment and the development of magnetic nanoparticles.</p>