Use of Control Charts to Define Diagnostic and Activities Reference Levels for PET/CT Studies in adults: a local study

Purpose – This article proposes a methodology, based on Statistical Process Control (SPC), to define reference values of levels and activities (DRL and ARL18FDG, respectively) used in PET/CT (Positron Emission Tomography with Computed Tomography) studies, as well as to build a monitoring tool to control the patients’ radiological activity at the Nuclear Medicine Department of Hospital Garcia de Orta (HGO).
Design/methodology/approach – In the first phase, the aim is to obtain the reference values for CTDIvol and DLP (for CT component) and administered activities (for PET component) (respectively DRL and ARL18FDG) for the standard patient (70 ± 10kg) and to estimate the parameters needed to construct the control chart later. In the second phase, the control chart for monitoring shall be implemented, using the ratio administered activity of 2-[18F]fluoro-2-desoxi-D-glucose (2-[18F]FDG) per patient weight.
Findings – Determining the values of DRL and ARL18FDG for auditing purposes, which shall be used as guides at the HGO Nuclear Medicine Department.
Social implications – In Portugal, the regulator has not yet defined diagnostic reference levels for nuclear medicine procedures. As such, SPC, through Control Charts, can be a useful tool for achieving this at the institutional level, since they make it possible to detect situations in which the administered activity is lower, or higher than that proposed for the standard patient. It may also be used to establish internal reference dose levels and to compare them with those reported in international scientific articles, leading to greater control of the institution, patient protection and, ultimately, functioning as an internal auditing tool.
Originality/value – With this study, it will be possible to establish reference values for for PET/CT scans in adults, both in terms of radiopharmaceutical administration of 2-[18F]FDG and use of ionizing radiation, respectively ARL18FDG and DRL,, at the HGO Nuclear Medicine Department in Portugal.

Positron Emission Tomography, Computed Tomography, Nuclear Medicine, Statistical Process Control and Control Charts