Low-dose radiation protocol using 3D mode in a BGO PET/CT.

BACKGROUND

The use of positron emission tomography combined with computed tomography (PET/CT) has brought about significant technological advancement in diagnostic imaging, and a number of PET/CT scanners with bismuth germanate detectors can perform imaging in both 2D and 3D acquisition modes. Nevertheless, certain image acquisition parameters and physical features of patients have to be considered when designing low-dose protocols in the 3D mode.

PURPOSE

The aim of this study was to compare images acquired in 2D and 3D modes and establish a low-dose protocol for use in PET/CT imaging, decreasing patient exposure to radiation without compromising results.

METHODS

A total of 30 patients, aged 4-72 years, participated in this prospective study, which was conducted at Albert Einstein Hospital, São Paulo, Brazil. Images were evaluated for picture quality, presence/absence of lesions and the number of lesions that were detectable in both acquisition modes.

RESULTS

The results consistently showed that the loss in image quality in the 3D mode did not affect exam interpretation and lesion detection when compared with 2D at higher dose and for a longer time.

CONCLUSIONS

We therefore conclude that administration of 3.7 MBq [(18)F]-fluorodeoxyglucose (FDG)/kg for an acquisition time of 3 min per FOV (field of view) is optimal for image acquisition in the 3D mode. This protocol, which reduces the acquisition time and radiation dose, is quite beneficial, especially for children.