News Column

Research Data from University of Melbourne Update Understanding of Nanoparticles

February 7, 2014

By a News Reporter-Staff News Editor at Health & Medicine Week -- Current study results on Nanoparticles have been published. According to news reporting originating from Melbourne, Australia, by NewsRx correspondents, research stated, "CT ventilation imaging is a novel functional lung imaging modality based on deformable image registration. The authors present the first validation study of CT ventilation using positron emission tomography with Ga-68-labeled nanoparticles (PET-Galligas)."

Our news editors obtained a quote from the research from the University of Melbourne, "The authors quantify this agreement for different CT ventilation metrics and PET reconstruction parameters. PET-Galligas ventilation scans were acquired for 12 lung cancer patients using a fourdimensional (4D) PET/CT scanner. CT ventilation images were then produced by applying B-spline deformable image registration between the respiratory correlated phases of the 4D-CT. The authors test four ventilation metrics, two existing and two modified. The two existing metrics model mechanical ventilation (alveolar air-flow) based on Hounsfield unit (HU) change (V-HU) or Jacobian determinant of deformation (V-Jac). The two modified metrics incorporate a voxel-wise tissue-density scaling (rho V-HU and rho V-Jac) and were hypothesized to better model the physiological ventilation. In order to assess the impact of PET image quality, comparisons were performed using both standard and respiratory-gated PET images with the former exhibiting better signal. Different median filtering kernels (sm = 0 or 3 mm) were also applied to all images. As in previous studies, similarity metrics included the Spearman correlation coefficient r within the segmented lung volumes, and Dice coefficient d(20) for the (0 - 20)th functional percentile volumes. The best agreement between CT and PET ventilation was obtained comparing standard PET images to the density-scaled HU metric (rho V-HU) with sm = 3 mm. This leads to correlation values in the ranges 0.22

According to the news editors, the research concluded: "CT ventilation imaging has clear potential for imaging regional air volume change in the lung, and further development is warranted."

For more information on this research see: Validating and improving CT ventilation imaging by correlating with ventilation 4D-PET/CT using Ga-68-labeled nanoparticles. Medical Physics, 2014;41(1):298-309. Medical Physics can be contacted at: Amer Assoc Physicists Medicine Amer Inst Physics, Ste 1 No 1, 2 Huntington Quadrangle, Melville, NY 11747-4502, USA. (American Association of Physicists in Medicine -; Medical Physics -

The news editors report that additional information may be obtained by contacting J. Kipritidis, University of Melbourne, Dept. of Med, Melbourne, Vic 3002, Australia. Additional authors for this research include S. Siva, M.S. Hofman, J. Callahan, R.J. Hicks and P.J. Keall (see also Nanoparticles).

Keywords for this news article include: Melbourne, Nanotechnology, Emerging Technologies, Australia and New Zealand

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Source: Health & Medicine Week

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