title: Multispectral Cerenkov luminescence tomography for small animal optical imaging.
abstract: Quite recently Cerenkov luminescence imaging (CLI) has been introduced as a novel pre-clinical imaging for the in vivo imaging of small animals such as mice. The CLI method is based on the detection of Cerenkov radiation (CR) generated by beta particles as they travel into the animal tissues with an energy such that Cerenkov emission condition is satisfied. This paper describes an image reconstruction method called multi spectral diffuse Cerenkov luminescence tomography (msCLT) in order to obtain 3D images from the detection of CR. The multispectral approach is based on a set of 2D planar images acquired using a number of narrow bandpass filters, and the distinctive information content at each wavelength is used in the 3D image reconstruction process. The proposed msCLT method was tested both in vitro and in vivo using 32P-ATP and all the images were acquired by using the IVIS 200 small animal optical imager (Caliper Life Sciences, Alameda USA). Source depth estimation and spatial resolution measurements were performed using a small capillary source placed between several slices of chicken breast. The theoretical Cerenkov emission spectrum and optical properties of chicken breast were used in the modelling of photon propagation. In vivo imaging was performed by injecting control nude mice with 10 MBq of 32P-ATP and the 3D tracer bio-distribution was reconstructed. Whole body MRI was acquired to provide an anatomical localization of the Cerenkov emission. The spatial resolution obtained from the msCLT reconstructed images of the capillary source showed that the FWHM is about 1.5 mm for a 6 mm depth. Co-registered MRI images showed that the Cerenkov emission regions matches fairly well with anatomical regions, such as the brain, heart and abdomen. Ex vivo imaging of the different organs such as intestine, brain, heart and ribs further confirms these findings. We conclude that in vivo 3D bio-distribution of a pure beta-minus emitting radiopharmaceutical such as 32P-ATP can be obtained using the msCLT reconstruction approach.
authors.affiliation: Medical Physics Department, San Raffaele Scientific Institute, Via Olgettina N. 60, Milan, Italy. spinelli.antonello@hsr.it
authors.forename: Antonello E
authors.initials: AE
authors.lastname: Spinelli
authors.forename: Chaincy
authors.initials: C
authors.lastname: Kuo
authors.forename: Brad W
authors.initials: BW
authors.lastname: Rice
authors.forename: Riccardo
authors.initials: R
authors.lastname: Calandrino
authors.forename: Pasquina
authors.initials: P
authors.lastname: Marzola
authors.forename: Andrea
authors.initials: A
authors.lastname: Sbarbati
authors.forename: Federico
authors.initials: F
authors.lastname: Boschi
mesh_terms: D000255:Adenosine Triphosphate / Q000493:pharmacokinetics; D000465:Algorithms; D000818:Animals; D001610:Beta Particles; D002196:Capillaries; D002645:Chickens; D003198:Computer Simulation; D004583:Electrons; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D049449:Luminescence; D008279:Magnetic Resonance Imaging; D051379:Mice; D008819:Mice, Nude; D008962:Models, Theoretical; D018482:Muscle, Skeletal / Q000098:blood supply / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D010761:Phosphorus Radioisotopes; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D014018:Tissue Distribution
chemical_list: D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate