###### Abstract  
P preclinical PET animal studies require immobilization of the animal, typically accomplished through the administration of anesthesia, which may affect the radiotracer biodistribution. The use of \({}^{18}\)F point sources attached to the rat head is one of the most promising methods for motion compensation in awake rat PET studies. However, the presence of radioactive markers may degrade image quality. In this study, we aimed to investigate the most favorable conditions for preclinical PET studies using awake rats with attached point sources. Firstly, we investigate the optimal activity conditions for the markers and rat-injected tracer using Monte Carlo simulations to determine the parameters of maximum detectability without compromising image quality. Additionally, we scrutinize the impact of delayed window correction for random events on marker detectability and overall image quality within these studies. Secondly, we present a method designed to mitigate the influence of rapid rat movements, which resulted in a medium loss of events of around 30%, primarily observed during the initial phase of the data acquisition. We validated our study with PET acquisitions from an awake rat within the acceptable conditions of activity and motion compensation parameters. This acquisition revealed an 8% reduction in resolution compared to a sedated animal, along with a 6% decrease in signal-to-noise ratio (SNR). These outcomes affirm the viability of our method for conducting awake preclinical brain studies. political image quality; awake PET; Monte Carlo; delayed window; random coincidences; anaesthesia; motion correction +
Footnote †: journal: Medical Imaging  
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Footnote †: journal: Medical Imaging  
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Footnote 1: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
To overcome this limitation, the focus on conducting studies with awake animals has gained importance in recent years. Several approaches have been taken in this field, including the use of restraining devices [5; 6; 7; 8; 9], scanners attached to the animals [10; 11], and motion tracking and correction techniques. Restraining animals during PET scans can limit the animal's movement but may result in immobilization stress, leading to altered uptake of radiotracers [5; 6]. Scanners attached to animals, such as the RatCAP [12; 13], offer an alternative approach but may also induce stress in the animal. Motion tracking and correction techniques are currently the most-studied approach, as they allow free animal motion and ensure that the animal is not stressed during the scan. Within the field of motion tracking and correction, several methods have been proposed. Optical markers [14; 15; 16; 17], natural head features [18], point clouds [19], and point sources [20; 21; 22] are some of the most widely studied techniques. Optical markers require the rat's head to be facing the tracking camera, and there may be some limitations when the marker is occluded or the bore of the scanner is small. Using natural head features eliminates the need for attaching markers, but to obtain enough distinctive features, it may be necessary to paint a black pattern on the animal's head. Point clouds use a combination of stereo vision and structured light projection to represent the 3D surface of the animal head as point clouds, which can then be used to determine its 3D pose. Finally, point sources attached to the rat head have been widely studied by [PERSON] et al. [3; 20]. This method uses the spatial location of the point sources in the PET data to calculate the head's pose [3]. This approach has shown promising results, making viable the acquisition of awake animal data without requiring any external devices. Given the potential of using point source markers for motion estimation, our study aimed to optimize the parameters of point source markers strategy, a novel approach in motion tracking and correction.