The popular article by Carmine Granata, titled “Applications of Quantum Physics in Medicine,” has been published in the special issue of the journal SAPERE (Dedalo) dedicated to the International Year of Quantum Science and Technology. A major leap forward in the progress of medicine and surgery has undoubtedly been possible thanks to both diagnostic imaging, which has enabled reliable and precise diagnoses, and certain therapeutic techniques based on the use of radiation and radiopharmaceuticals. The article focuses primarily on diagnostic imaging (anatomical, morphological, and functional) that uses quantum physics principles. In particular, diagnostic techniques will be considered such as: nuclear magnetic resonance imaging (NMR), based on a quantum phenomenon first observed in 1946 by physicists Felix Bloch and Edward Purcell; positron-electron tomography (PET), based on the annihilation of electrons and positrons emitted following the decay of certain radioactive elements; Single-photon emission computed tomography (SPECT) and scintigraphy based on the emission of gamma rays from radiopharmaceuticals; and magnetoencephalography, based on the measurement of the very weak magnetic fields produced by neuronal activity in the brain using ultrasensitive quantum sensors. In addition to the operating principles, the diagnostic uses and recent developments are highlighted. Finally, the potential biomedical applications of quantum imaging based on photon entanglement are also mentioned, as well as some recent therapeutic techniques such as hadrontherapy based on the use of collimated beams of protons or carbon-11.