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Báo cáo toán học: " Yttrium-90-labeled microsphere tracking during liver selective internal radiotherapy by bremsstrahlung pinhole SPECT: feasibility study and evaluation in an abdominal phantom"

Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học được đăng trên tạp chí toán học quốc tế đề tài: Yttrium-90-labeled microsphere tracking during liver selective internal radiotherapy by bremsstrahlung pinhole SPECT: feasibility study and evaluation in an abdominal phantom | Walrand et al. EJNMMI Research 2011 1 32 http www.ejnmmires.eom content 1 1 32 9 EJNMMI Research a SpringerOpen Journal ORIGINAL RESEARCH Open Access Yttrium-90-labeled microsphere tracking during liver selective internal radiotherapy by bremsstrahlung pinhole SPECT feasibility study and evaluation in an abdominal phantom Stephan Walrand1 Michel Hesse2 Georges Demonceau2 Stanislas Pauwels1 and Frangois Jamar1 Abstract Background The purpose of the study is to evaluate whether a pinhole collimator is better adapted to bremsstrahlung single photon emission computed tomography SPECT than parallel-hole collimators and in the affirmative to evaluate whether pinhole bremsstrahlung SPECT including a simple model of the scatter inside the patient could provide a fast dosimetry assessment in liver selective internal radiotherapy SIRT . Materials and methods Bremsstrahlung SPECT of an abdominal-shaped phantom including one cold and five hot spheres was performed using two long-bore parallel-hole collimators a medium-energy general-purpose MEGP and a high-energy general-purpose HEGP and also using a medium-energy pinhole MEPH collimator. In addition ten helical MEPH SPECTs acquisition time 3.6 min of a realistic liver-SIRT phantom were also acquired. Results Without scatter correction for SPECT MEPH SPECT provided a significantly better contrast recovery coefficient CRC than MEGP and HEGP SPECTs. The CRCs obtained with MEPH SPECT were still improved with the scatter correction and became comparable to those obtained with positron-emission tomography PET for the 36- 30- cold 28- and 24-mm-diameter spheres CRC 1.09 0.59 0.91 and 0.69 respectively for SPECT and CRC 1.07 0.56 0.84 and 0.63 respectively for PET. However MEPH SPECT gave the best CRC for the 19-mm-diameter sphere CRC 0.56 for SPECT and CRC 0.01 for PET. The 3.6-min helical MEPH SPECT provided accurate and reproducible activity estimation for the liver-SIRT phantom relative deviation 10 1 . Conclusion Bremsstrahlung