 SPECT is often skipped if the patient has pulmonary hypertension.It is also possible to perform the scan with positron emission tomography (PET) rather than conventional gamma camera scintigraphy.This has been performed with Gallium-68 labelled carbon nanoparticles (Galligas) using a conventional Technegas machine for ventilation images, and with Gallium-68 labelled MAA (Ga68-MAA) for perfusion images.