RESUMEN
The RAYCAN Trans-PET/CT X5 is a preclinical positron emission tomography and computed tomography (PET/CT) system intended for in vivo imaging of rats and mice, featuring all-digital readout electronics for PET data acquisition. The National Electrical Manufacturers Association (NEMA) NU 4-2008 performance evaluation was conducted on the RAYCAN Trans-PET/CT X5 in addition to assessing in vivo imaging performance of the system on live animals. The performance characteristics of the system were evaluated, including system spatial resolution, count rate performance, sensitivity and image quality. The system imaging performance is assessed in dynamic in vivo PET imaging. The system resolution defined as full width half maximum (FWHM) was 2.07 mm, 2.11 mm and 1.31 mm for the tangential, radial and axial resolution, respectively, at the center of the field of view. The peak noise equivalent count rate (NECR) values measured were 61 kcps at 0.19 MBq ml-1 for the rat size phantom and 126 kcps at 1.53 MBq ml-1 for the mouse size phantom. Scatter fractions were 24% and 14% for the rat and mouse phantom. The measured peak sensitivity of the system was 1.70%. Image quality in static imaging was deemed sufficient based on the image quality phantom study, with average activity concentration of 155 ± 8.6 kBq ml-1 and image uniformity of 5.57% when using two-dimensional filtered backprojection algorithm (2D-FBP). Rods in the image quality phantom were visualized easily up to 2 mm in size. In dynamic in vivo PET imaging, time-activity-curves from several regions were successfully measured, characterizing the radioactivity distribution in myocardial blood pool, liver, left ventricle and the lung. In conclusion, the RAYCAN Trans-PET/CT X5 system can be considered a suitable option for basic imaging needs in preclinical imaging.
Asunto(s)
Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones/instrumentación , Tomografía Computarizada por Tomografía de Emisión de Positrones/normas , Animales , Ratones , RatasRESUMEN
Psoriasis (Ps), psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are common diseases dependent on environmental factors that activate the immune system in unknown ways. Mannan is a group of polysaccharides common in the environment; they are potentially pathogenic, because at least some of them induce Ps-, PsA- and RA-like inflammation in mice. Here, we used positron emission tomography/computed tomography to examine in-vivo transport and spread of mannan labelled with fluorine-18 [18 F]. The results showed that mannan was transported to joints (knee) and bone marrow (tibia) of mice within 6 h after intraperitoneal injection. The time it took to transport mannan, and its presence in blood, indicated cellular transport of mannan within the circulatory system. In addition, mannan was filtered mainly through the spleen and liver. [18 F]fluoromannan was excreted via kidneys, small intestine and, to some extent, the mouth. In conclusion, mannan reaches joints rapidly after injection, which may explain why mannan-induced inflammatory disease is targeted to these tissues.
Asunto(s)
Artritis Psoriásica/inmunología , Artritis Reumatoide/inmunología , Sistema Inmunológico/metabolismo , Articulaciones/metabolismo , Mananos/metabolismo , Psoriasis/inmunología , Animales , Transporte Biológico , Circulación Sanguínea , Modelos Animales de Enfermedad , Exposición a Riesgos Ambientales , Radioisótopos de Flúor/química , Humanos , Inyecciones Intraperitoneales , Articulaciones/patología , Mananos/química , Ratones , Ratones Mutantes , Tomografía Computarizada por Tomografía de Emisión de Positrones , Piel/patologíaRESUMEN
OBJECTIVE: Lyme borreliosis (LB) is a tick-borne infectious disease caused by Borrelia burgdorferi spirochaetes, which are able to disseminate from the tick-bite site to distant organs. Mouse models are widely used to study LB and especially Lyme arthritis (LA), but only a few whole-animal in vivo imaging studies on the pathogenesis of B. burgdorferi infection in mice have been published so far. The existing imaging techniques have their drawbacks and, therefore, novel tools to complement the array of available LB imaging methodologies are needed. METHOD: The applicability of positron emission tomography combined with computed tomography (PET/CT) imaging was evaluated as a method to monitor LB and especially LA in the C3H/HeN mouse model infected with wild-type B. burgdorferi N40 bacteria. The imaging results were compared with the traditional LA analysis methods, such as tibiotarsal joint swelling and histopathological assessment of joint inflammation. RESULTS: PET/CT imaging provided high-resolution images with quantitative information on the spatial and temporal distribution of the [18F]fluorodeoxyglucose ([18F]FDG) tracer in B. burgdorferi-infected mice. The [18F]FDG accumulated in the affected joints and activated lymph nodes of infected mice, while the tracer signal could not be visualized in these organs in uninfected control animals. Importantly, in vivo PET/CT imaging data were in agreement with the histopathological scoring of inflammation of mouse joints. CONCLUSION: PET/CT imaging with [18F]FDG is a reliable method to longitudinally monitor the development and progression of B. burgdorferi infection-induced inflammation in vivo in mouse joints.