Detection limit of a lutetium based non-paralizable PET detector

TL;DR

This paper investigates the detection limits of a lutetium-based PET detector affected by intrinsic radioactivity, proposing a method to estimate the minimum detectable activity considering dead time effects, with implications for various detectors.

Contribution

It introduces a novel method to estimate the detection limit of lutetium-based PET detectors accounting for dead time and intrinsic radioactivity effects.

Findings

The method accurately estimates the minimum detectable activity for the PET prototype.

Intrinsic lutetium radioactivity degrades the detection of faint signals.

The dead time correction formalism is applicable to other non-paralizable detectors.

Abstract

The effect of the intrinsic lutetium radioactivity on the detection performances of a LYSO based in-beam PET prototype used for quality control of hadron therapy treatments is studied. This radioactivity leads to a background that degrades the measurement of the $\beta$ + signal. In particular, it prevents the measurement of faint signals originating from low activity $\beta$ + sources. This paper presents a method to estimate the minimum $\beta$ + activity that can be measured for any acquisition time taking into account the non-extensible dead time of the detector. This method is illustrated with experimental data collected with the in-beam PET prototype. The results presented in this paper are therefore specific to this detector. The method can however be applied in other contexts, either to other lutetium based PET detectors or even to non-PET detectors affected by lutetium radioactivity. The dead time correction formalism can also be used generally to scale signal and background yields in any non-paralizable detector, even those in which the background is not due to the presence of intrinsic radioactivity.