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Quantitative and qualitative assessment of Yttrium-90 PET/CT imaging.

Attarwala AA, Molina-Duran F, Büsing KA, Schönberg SO, Bailey DL, Willowson K, Glatting G - PLoS ONE (2014)

Bottom Line: For the smaller diameter spheres, the PSF algorithm with TOF and single bed acquisition provided a comparatively better activity recovery.Quantification of Y-90 using Biograph mCT PET/CT is possible with a reasonable accuracy, the limitations being the size of the lesion and the activity concentration present.At this stage, based on our study, it seems advantageous to use different protocols depending on the size of the lesion.

View Article: PubMed Central - PubMed

Affiliation: Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.

ABSTRACT
Yttrium-90 is known to have a low positron emission decay of 32 ppm that may allow for personalized dosimetry of liver cancer therapy with (90)Y labeled microspheres. The aim of this work was to image and quantify (90)Y so that accurate predictions of the absorbed dose can be made. The measurements were performed within the QUEST study (University of Sydney, and Sirtex Medical, Australia). A NEMA IEC body phantom containing 6 fillable spheres (10-37 mm ∅) was used to measure the 90Y distribution with a Biograph mCT PET/CT (Siemens, Erlangen, Germany) with time-of-flight (TOF) acquisition. A sphere to background ratio of 8:1, with a total (90)Y activity of 3 GBq was used. Measurements were performed for one week (0, 3, 5 and 7 d). he acquisition protocol consisted of 30 min-2 bed positions and 120 min-single bed position. Images were reconstructed with 3D ordered subset expectation maximization (OSEM) and point spread function (PSF) for iteration numbers of 1-12 with 21 (TOF) and 24 (non-TOF) subsets and CT based attenuation and scatter correction. Convergence of algorithms and activity recovery was assessed based on regions-of-interest (ROI) analysis of the background (100 voxels), spheres (4 voxels) and the central low density insert (25 voxels). For the largest sphere, the recovery coefficient (RC) values for the 30 min -2-bed position, 30 min-single bed and 120 min-single bed were 1.12 ± 0.20, 1.14 ± 0.13, 0.97 ± 0.07 respectively. For the smaller diameter spheres, the PSF algorithm with TOF and single bed acquisition provided a comparatively better activity recovery. Quantification of Y-90 using Biograph mCT PET/CT is possible with a reasonable accuracy, the limitations being the size of the lesion and the activity concentration present. At this stage, based on our study, it seems advantageous to use different protocols depending on the size of the lesion.

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Related in: MedlinePlus

Transverse sections of the phantom reconstructed with 30 min-2 bed position, 30 min and 120 min single bed acquisitions and a matrix size of 400 and Gaussian filtering with FWHM of 5 mm for 21 subsets and 1–3 iterations of PSF TOF algorithms.Note that the smallest sphere is an empty sphere [40].
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pone-0110401-g002: Transverse sections of the phantom reconstructed with 30 min-2 bed position, 30 min and 120 min single bed acquisitions and a matrix size of 400 and Gaussian filtering with FWHM of 5 mm for 21 subsets and 1–3 iterations of PSF TOF algorithms.Note that the smallest sphere is an empty sphere [40].

Mentions: Figure 2 shows the effect of increasing iterations and different acquisition times on the reconstructed images. The visual quality of the images has a higher image contrast for the reconstructions made with a longer acquisition time. The 13 mm sphere (second smallest sphere) is easier to discern for the single bed 30 min and 120 min acquisitions in list mode as compared to 30 min static acquisition mode with 2 bed positions. Also the lung insert (cold region) is more clearly visible with the longer acquisition.


Quantitative and qualitative assessment of Yttrium-90 PET/CT imaging.

Attarwala AA, Molina-Duran F, Büsing KA, Schönberg SO, Bailey DL, Willowson K, Glatting G - PLoS ONE (2014)

Transverse sections of the phantom reconstructed with 30 min-2 bed position, 30 min and 120 min single bed acquisitions and a matrix size of 400 and Gaussian filtering with FWHM of 5 mm for 21 subsets and 1–3 iterations of PSF TOF algorithms.Note that the smallest sphere is an empty sphere [40].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219690&req=5

pone-0110401-g002: Transverse sections of the phantom reconstructed with 30 min-2 bed position, 30 min and 120 min single bed acquisitions and a matrix size of 400 and Gaussian filtering with FWHM of 5 mm for 21 subsets and 1–3 iterations of PSF TOF algorithms.Note that the smallest sphere is an empty sphere [40].
Mentions: Figure 2 shows the effect of increasing iterations and different acquisition times on the reconstructed images. The visual quality of the images has a higher image contrast for the reconstructions made with a longer acquisition time. The 13 mm sphere (second smallest sphere) is easier to discern for the single bed 30 min and 120 min acquisitions in list mode as compared to 30 min static acquisition mode with 2 bed positions. Also the lung insert (cold region) is more clearly visible with the longer acquisition.

Bottom Line: For the smaller diameter spheres, the PSF algorithm with TOF and single bed acquisition provided a comparatively better activity recovery.Quantification of Y-90 using Biograph mCT PET/CT is possible with a reasonable accuracy, the limitations being the size of the lesion and the activity concentration present.At this stage, based on our study, it seems advantageous to use different protocols depending on the size of the lesion.

View Article: PubMed Central - PubMed

Affiliation: Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.

ABSTRACT
Yttrium-90 is known to have a low positron emission decay of 32 ppm that may allow for personalized dosimetry of liver cancer therapy with (90)Y labeled microspheres. The aim of this work was to image and quantify (90)Y so that accurate predictions of the absorbed dose can be made. The measurements were performed within the QUEST study (University of Sydney, and Sirtex Medical, Australia). A NEMA IEC body phantom containing 6 fillable spheres (10-37 mm ∅) was used to measure the 90Y distribution with a Biograph mCT PET/CT (Siemens, Erlangen, Germany) with time-of-flight (TOF) acquisition. A sphere to background ratio of 8:1, with a total (90)Y activity of 3 GBq was used. Measurements were performed for one week (0, 3, 5 and 7 d). he acquisition protocol consisted of 30 min-2 bed positions and 120 min-single bed position. Images were reconstructed with 3D ordered subset expectation maximization (OSEM) and point spread function (PSF) for iteration numbers of 1-12 with 21 (TOF) and 24 (non-TOF) subsets and CT based attenuation and scatter correction. Convergence of algorithms and activity recovery was assessed based on regions-of-interest (ROI) analysis of the background (100 voxels), spheres (4 voxels) and the central low density insert (25 voxels). For the largest sphere, the recovery coefficient (RC) values for the 30 min -2-bed position, 30 min-single bed and 120 min-single bed were 1.12 ± 0.20, 1.14 ± 0.13, 0.97 ± 0.07 respectively. For the smaller diameter spheres, the PSF algorithm with TOF and single bed acquisition provided a comparatively better activity recovery. Quantification of Y-90 using Biograph mCT PET/CT is possible with a reasonable accuracy, the limitations being the size of the lesion and the activity concentration present. At this stage, based on our study, it seems advantageous to use different protocols depending on the size of the lesion.

Show MeSH
Related in: MedlinePlus