Print Email Facebook Twitter Experimental Validation of an Efficient Fan-Beam Calibration Procedure for k -Nearest Neighbor Position Estimation in Monolithic Scintillator Detectors Title Experimental Validation of an Efficient Fan-Beam Calibration Procedure for k -Nearest Neighbor Position Estimation in Monolithic Scintillator Detectors Author Borghi, G. Tabacchini, V. Seifert, S. Schaart, D.R. Faculty Applied Sciences Department RST/Radiation, Science and Technology Date 2015-02-06 Abstract Monolithic scintillator detectors can achieve excellent spatial resolution and coincidence resolving time. However, their practical use for positron emission tomography (PET) and other applications in the medical imaging field is still limited due to drawbacks of the different methods used to estimate the position of interaction. Common statistical methods for example require the collection of an extensive dataset of reference events with a narrow pencil beam aimed at a fine grid of reference positions. Such procedures are time consuming and not straightforwardly implemented in systems composed of many detectors. Here, we experimentally demonstrate for the first time a new calibration procedure for k-nearest neighbor ( k-NN) position estimation that utilizes reference data acquired with a fan beam. The procedure is tested on two detectors consisting of 16 mm ×16 mm ×10 mm and 16 mm ×16 mm ×20 mm monolithic, Ca-codoped LSO:Ce crystals and digital photon counter (DPC) arrays. For both detectors, the spatial resolution and the bias obtained with the new method are found to be practically the same as those obtained with the previously used method based on pencil-beam irradiation, while the calibration time is reduced by a factor of ~ 20. Specifically, a FWHM of ~ 1.1 mm and a FWTM of ~ 2.7 mm were obtained using the fan-beam method with the 10 mm crystal, whereas a FWHM of ~ 1.5 mm and a FWTM of ~ 6 mm were achieved with the 20 mm crystal. Using a fan beam made with a ~ 4.5 MBq 22Na point-source and a tungsten slit collimator with 0.5 mm aperture, the total measurement time needed to acquire the reference dataset was ~ 3 hours for the thinner crystal and ~ 2 hours for the thicker one. To reference this document use: http://resolver.tudelft.nl/uuid:fe04a942-6fc9-46c1-9c9a-b9e94dab1de3 DOI https://doi.org/10.1109/TNS.2014.2375557 Publisher IEEE ISSN 0018-9499 Source IEEE Transactions on Nuclear Science, 62 (1), 2015 Part of collection Institutional Repository Document type journal article Rights © 2015 IEEE Files PDF Borghi_2015.pdf 1.5 MB Close viewer /islandora/object/uuid:fe04a942-6fc9-46c1-9c9a-b9e94dab1de3/datastream/OBJ/view