title: Monte Carlo simulation of PET images for injection dose optimization.
abstract: When a patient is examined by positron emission tomography (PET), radiotracer dose amount (activity) has to be determined. However, the rules for activity correction according to patients' weight used nowadays do not correspond with practical experience. Very high image quality is achieved for slim patients, whereas noisy images are produced for obese patients. There is opportunity to modify the correction rule with the aim to equalize image quality within the broad spectrum of patients and to diminish radiation risk to slim patients, with special importance for children. We have built a model of a particular PET scanner and approximated human trunk, which is our region of interest, by a cylindrical model with segments of liver, outer adipose tissue, and the rest. We have performed Monte Carlo simulations of PET imaging using the GATE simulation package. Under reasonably simplifying assumptions and for special parameters, we have developed curves that recommend amount of injected activity based on body parameters to give PET images of constant quality, the quality being expressed in terms of noise equivalent counts. The dependence qualitatively differs from the rules used in clinical practice nowadays, and the results indicate potential for improvement.
authors.affiliation: Institute of Information Theory and Automation, Academy of Sciences of the Czech Republic, Pod Vodárenskou věží 4, 182 08 Praha 8, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Boldyš
authors.forename: Jiří
authors.initials: J
authors.lastname: Dvořák
authors.forename: Magdaléna
authors.initials: M
authors.lastname: Skopalová
authors.forename: Otakar
authors.initials: O
authors.lastname: Bělohlávek
mesh_terms: D015992:Body Mass Index; D049628:Body Size / Q000502:physiology*; D003198:Computer Simulation; D054796:Drug Dosage Calculations; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008954:Models, Biological; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011829:Radiation Dosage; D011849:Radioactive Tracers; D014057:Tomography, X-Ray Computed; D060726:Torso / Q000000981:diagnostic imaging / Q000502:physiology
chemical_list: D011849:Radioactive Tracers
keywords: Monte Carlo simulation; biological system modeling; image quality; positron emission tomography