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Sci—Thur AM: YIS ‐ 08: Constructing an Attenuation map for a PET/MR Breast coil
Author(s) -
Patrick John C.,
So Aaron,
Butler John,
Faul David,
Yartsev Slav,
Thompson Terry,
Prato Frank S.,
Gaede Stewart
Publication year - 2014
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4894949
Subject(s) - attenuation , electromagnetic coil , correction for attenuation , signal (programming language) , breast imaging , radiofrequency coil , scanner , nuclear medicine , iterative reconstruction , magnetic resonance imaging , imaging phantom , materials science , breast cancer , physics , computer science , optics , medicine , artificial intelligence , radiology , cancer , mammography , quantum mechanics , programming language
In 2013, around 23000 Canadian women and 200 Canadian men were diagnosed with breast cancer. An estimated 5100 women and 55 men died from the disease. Using the sensitivity of MRI with the selectivity of PET, PET/MRI combines anatomical and functional information within the same scan and could help with early detection in high‐risk patients. MRI requires radiofrequency coils for transmitting energy and receiving signal but the breast coil attenuates PET signal. To correct for this PET attenuation, a 3‐dimensional map of linear attenuation coefficients (μ‐map) of the breast coil must be created and incorporated into the PET reconstruction process. Several approaches have been proposed for building hardware μ‐maps, some of which include the use of conventional kVCT and Dual energy CT. These methods can produce high resolution images based on the electron densities of materials that can be converted into μ‐maps. However, imaging hardware containing metal components with photons in the kV range is susceptible to metal artifacts. These artifacts can compromise the accuracy of the resulting μ‐map and PET reconstruction; therefore high‐Z components should be removed. We propose a method for calculating μ‐maps without removing coil components, based on megavoltage (MV) imaging with a linear accelerator that has been detuned for imaging at 1.0MeV. Containers of known geometry with F18 were placed in the breast coil for imaging. A comparison between reconstructions based on the different μ‐map construction methods was made. PET reconstructions with our method show a maximum of 6% difference over the existing kVCT‐based reconstructions.