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Scatter effects of MR components in PET-MR inserts

Vincent Keereman, Stefaan Vandenberghe UGent, Jan De Beenhouwer UGent, Roel Van Holen UGent, Steven Staelens UGent, Volkmar Schulz and Torsten Solf (2009) IEEE Nuclear Science Symposium Conference Record. p.3804-3807
abstract
System design research for upcoming PET-MR scanners has mainly focussed on the effect of the high magnetic field on PET performance and on the influence of the PET scanner inside the MR bore on MR image quality. However, the presence of MR components close to the PET detectors could also have an influence on PET performance. We have investigated these effects in a simulation study of the preclinical PET-MR insert and of the proposed integrated whole-body system of the HYPERimage project. Simulations were performed with the ProcessGATE extension of the GATE simulation framework, which makes it possible to determine the fractions of total scatter caused by different components. The preclinical insert was simulated inside a clinical MR scanner. All components of the clinical system and the preclinical insert were modeled in realistic dimensions and materials. The PET detector consisted of 10 detector blocks on a 100 mm radius cylinder, each containing a 44 (tangential) by 72 (axial) array of LYSO crystals. The crystal dimensions were 1.3 * 1.3 * 10 mm. The energy window was set to 250 - 750 keV. The integrated whole-body system was modeled as the same clinical MR system with a split gradient coil and PET detector blocks between both parts of the split gradient coil. The PET detector blocks in the whole-body system consisted of 22 detector blocks on a 35 cm radius cylinder containing 22 (tangential) by 43 (axial) LYSO crystals. The crystal dimensions were 4 * 4 * 22 mm. The energy window in this configuration was 410 - 700 keV. A uniform cylinder (radius 5 mm, length 100 mm) filled with 1 MBq of 18F was simulated in both the preclinical insert and the whole-body system. The simulated time was 1s yielding one million simulated decays. In the preclinical insert only 47 % of detected singles were unscattered. The clinical system and precinical insert accounted for respectively 38 % and 15 % of scattered photons. On the coincidences level the influence of the clinical system was much smaller (17 %), while the scatter effect of the insert increased (20%). In the clinical system the gradient coils scatter the largest fraction of photons (58 %). In the insert over 65 % of scatter is caused by the table and the RF screen. In the integrated whole-body system 44 % of detected singles were scattered. At coincidence level this fraction was reduced to 34 %. The largest amount of scattered coincidences is caused by the RF screen. In conclusion, it is clear that putting MR components within or close to the FOV of a PET scanner can cause significant scatter. The scattering effect of the MR components should be taken into account in the design phase.
Please use this url to cite or link to this publication:
author
organization
year
type
conference (proceedingsPaper)
publication status
published
subject
keyword
magnetic fields, Compton effect, nuclear electronics, position sensitive particle detectors, positron emission tomography, MR components scatter effects, PET-MR scanners, magnetic field effect, MR image quality, PET detectors, GATE simulation framework, HYPERimage project, image scanners, LYSO crystals array, split gradient coil, RF screen
in
IEEE Nuclear Science Symposium Conference Record
editor
Bo Yu
issue title
2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5
pages
3804 - 3807
publisher
IEEE
place of publication
Piscataway, NJ, USA
conference name
2009 IEEE Nuclear Science Symposium Conference
conference location
Orlando, FL, USA
conference start
2009-10-25
conference end
2009-10-31
Web of Science type
Proceedings Paper
Web of Science id
000280505102093
ISSN
1082-3654
ISBN
9781424439614
DOI
10.1109/NSSMIC.2009.5401898
language
English
UGent publication?
yes
classification
P1
id
806681
handle
http://hdl.handle.net/1854/LU-806681
date created
2009-12-10 15:26:53
date last changed
2017-01-02 09:52:55
@inproceedings{806681,
  abstract     = {System design research for upcoming PET-MR scanners has mainly focussed on the effect of the high magnetic field on PET performance and on the influence of the PET scanner inside the MR bore on MR image quality. However, the presence of MR components close to the PET detectors could also have an influence on PET performance. We have investigated these effects in a simulation study of the preclinical PET-MR insert and of the proposed integrated whole-body system of the HYPERimage project. Simulations were performed with the ProcessGATE extension of the GATE simulation framework, which makes it possible to determine the fractions of total scatter caused by different components. The preclinical insert was simulated inside a clinical MR scanner. All components of the clinical system and the preclinical insert were modeled in realistic dimensions and materials. The PET detector consisted of 10 detector blocks on a 100 mm radius cylinder, each containing a 44 (tangential) by 72 (axial) array of LYSO crystals. The crystal dimensions were 1.3 * 1.3 * 10 mm. The energy window was set to 250 - 750 keV. The integrated whole-body system was modeled as the same clinical MR system with a split gradient coil and PET detector blocks between both parts of the split gradient coil. The PET detector blocks in the whole-body system consisted of 22 detector blocks on a 35 cm radius cylinder containing 22 (tangential) by 43 (axial) LYSO crystals. The crystal dimensions were 4 * 4 * 22 mm. The energy window in this configuration was 410 - 700 keV. A uniform cylinder (radius 5 mm, length 100 mm) filled with 1 MBq of 18F was simulated in both the preclinical insert and the whole-body system. The simulated time was 1s yielding one million simulated decays. In the preclinical insert only 47 \% of detected singles were unscattered. The clinical system and precinical insert accounted for respectively 38 \% and 15 \% of scattered photons. On the coincidences level the influence of the clinical system was much smaller (17 \%), while the scatter effect of the insert increased (20\%). In the clinical system the gradient coils scatter the largest fraction of photons (58 \%). In the insert over 65 \% of scatter is caused by the table and the RF screen. In the integrated whole-body system 44 \% of detected singles were scattered. At coincidence level this fraction was reduced to 34 \%. The largest amount of scattered coincidences is caused by the RF screen. In conclusion, it is clear that putting MR components within or close to the FOV of a PET scanner can cause significant scatter. The scattering effect of the MR components should be taken into account in the design phase.},
  author       = {Keereman, Vincent and Vandenberghe, Stefaan and De Beenhouwer, Jan and Van Holen, Roel and Staelens, Steven and Schulz, Volkmar and Solf, Torsten},
  booktitle    = {IEEE Nuclear Science Symposium Conference Record},
  editor       = {Yu, Bo},
  isbn         = {9781424439614},
  issn         = {1082-3654},
  keyword      = {magnetic fields,Compton effect,nuclear electronics,position sensitive particle detectors,positron emission tomography,MR components scatter effects,PET-MR scanners,magnetic field effect,MR image quality,PET detectors,GATE simulation framework,HYPERimage project,image scanners,LYSO crystals array,split gradient coil,RF screen},
  language     = {eng},
  location     = {Orlando, FL, USA},
  pages        = {3804--3807},
  publisher    = {IEEE},
  title        = {Scatter effects of MR components in PET-MR inserts},
  url          = {http://dx.doi.org/10.1109/NSSMIC.2009.5401898},
  year         = {2009},
}

Chicago
Keereman, Vincent, Stefaan Vandenberghe, Jan De Beenhouwer, Roel Van Holen, Steven Staelens, Volkmar Schulz, and Torsten Solf. 2009. “Scatter Effects of MR Components in PET-MR Inserts.” In IEEE Nuclear Science Symposium Conference Record, ed. Bo Yu, 3804–3807. Piscataway, NJ, USA: IEEE.
APA
Keereman, V., Vandenberghe, S., De Beenhouwer, J., Van Holen, R., Staelens, S., Schulz, V., & Solf, T. (2009). Scatter effects of MR components in PET-MR inserts. In Bo Yu (Ed.), IEEE Nuclear Science Symposium Conference Record (pp. 3804–3807). Presented at the 2009 IEEE Nuclear Science Symposium Conference, Piscataway, NJ, USA: IEEE.
Vancouver
1.
Keereman V, Vandenberghe S, De Beenhouwer J, Van Holen R, Staelens S, Schulz V, et al. Scatter effects of MR components in PET-MR inserts. In: Yu B, editor. IEEE Nuclear Science Symposium Conference Record. Piscataway, NJ, USA: IEEE; 2009. p. 3804–7.
MLA
Keereman, Vincent, Stefaan Vandenberghe, Jan De Beenhouwer, et al. “Scatter Effects of MR Components in PET-MR Inserts.” IEEE Nuclear Science Symposium Conference Record. Ed. Bo Yu. Piscataway, NJ, USA: IEEE, 2009. 3804–3807. Print.