Abstract
Position-sensitive avalanche photodiodes (PSAPDs) are gaining widespread acceptance in modern PET scanner designs, and owing to their relative insensitivity to magnetic fields, especially in those that are MRI-compatible. Flood histograms in PET scanners are used to determine the crystal of annihilation photon interaction and hence, for detector characterization and routine quality control. For PET detectors that use PSAPDs, flood histograms show a characteristic pincushion distortion when Anger logic is used for event positioning. A small rotation in the flood histogram is also observed when the detectors are placed in a magnetic field. We first present a general purpose automatic method for spatial distortion correction for flood histograms of PSAPD-based PET detectors when placed both inside and outside a MRI scanner. Analytical formulae derived for this scheme are based on a hybrid approach that combines desirable properties from two existing event positioning schemes. The rotation of the flood hist gram due to the magnetic field is determined iteratively and is accounted for in the scheme. We then provide implementation details of a method for crystal identification we have previously proposed and evaluate it for cases when the PET scanner both outside and in a magnetic field. In this scheme, Fourier analysis is used to generate a lower-order spatial approximation of the distortion-corrected PSAPD flood histogram, which we call the 'template'. The template is then registered to the flood histogram using a diffeomorphic iterative intensity-based warping scheme. The calculated deformation field is then applied to the segmentation of the template to obtain a segmentation of the flood histogram. A manual correction tool is also developed for exceptional cases. We present a quantitative assessment of the proposed distortion correction scheme and crystal identification method against conventional methods. Our results indicate that our proposed methods lead to a large reduction in manual labor and indeed can outinely be used for calibration and characterization studies in MRI-compatible PET scanners based on PSAPDs.
| Original language | English (US) |
|---|---|
| Title of host publication | IEEE Nuclear Science Symposium Conference Record |
| Pages | 5045-5052 |
| Number of pages | 8 |
| DOIs | |
| State | Published - 2008 |
| Event | 2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008 - Dresden, Germany Duration: Oct 19 2008 → Oct 25 2008 |
Other
| Other | 2008 IEEE Nuclear Science Symposium Conference Record, NSS/MIC 2008 |
|---|---|
| Country | Germany |
| City | Dresden |
| Period | 10/19/08 → 10/25/08 |
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Keywords
- PETIMRI, PSAPD, Spatial distortion correction, Crystal identification
ASJC Scopus subject areas
- Radiation
- Nuclear and High Energy Physics
- Radiology Nuclear Medicine and imaging
Cite this
Spatial distortion correction and crystal identification for position-sensitive avalanche photodiode-based PET scanners. / Chaudhari, Abhijit; Joshi, Anand A.; Wu, Yibao; Leahy, Richard M.; Cherry, Simon R; Badawi, Ramsey D.
IEEE Nuclear Science Symposium Conference Record. 2008. p. 5045-5052 4774373.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Spatial distortion correction and crystal identification for position-sensitive avalanche photodiode-based PET scanners
AU - Chaudhari, Abhijit
AU - Joshi, Anand A.
AU - Wu, Yibao
AU - Leahy, Richard M.
AU - Cherry, Simon R
AU - Badawi, Ramsey D
PY - 2008
Y1 - 2008
N2 - Position-sensitive avalanche photodiodes (PSAPDs) are gaining widespread acceptance in modern PET scanner designs, and owing to their relative insensitivity to magnetic fields, especially in those that are MRI-compatible. Flood histograms in PET scanners are used to determine the crystal of annihilation photon interaction and hence, for detector characterization and routine quality control. For PET detectors that use PSAPDs, flood histograms show a characteristic pincushion distortion when Anger logic is used for event positioning. A small rotation in the flood histogram is also observed when the detectors are placed in a magnetic field. We first present a general purpose automatic method for spatial distortion correction for flood histograms of PSAPD-based PET detectors when placed both inside and outside a MRI scanner. Analytical formulae derived for this scheme are based on a hybrid approach that combines desirable properties from two existing event positioning schemes. The rotation of the flood hist gram due to the magnetic field is determined iteratively and is accounted for in the scheme. We then provide implementation details of a method for crystal identification we have previously proposed and evaluate it for cases when the PET scanner both outside and in a magnetic field. In this scheme, Fourier analysis is used to generate a lower-order spatial approximation of the distortion-corrected PSAPD flood histogram, which we call the 'template'. The template is then registered to the flood histogram using a diffeomorphic iterative intensity-based warping scheme. The calculated deformation field is then applied to the segmentation of the template to obtain a segmentation of the flood histogram. A manual correction tool is also developed for exceptional cases. We present a quantitative assessment of the proposed distortion correction scheme and crystal identification method against conventional methods. Our results indicate that our proposed methods lead to a large reduction in manual labor and indeed can outinely be used for calibration and characterization studies in MRI-compatible PET scanners based on PSAPDs.
AB - Position-sensitive avalanche photodiodes (PSAPDs) are gaining widespread acceptance in modern PET scanner designs, and owing to their relative insensitivity to magnetic fields, especially in those that are MRI-compatible. Flood histograms in PET scanners are used to determine the crystal of annihilation photon interaction and hence, for detector characterization and routine quality control. For PET detectors that use PSAPDs, flood histograms show a characteristic pincushion distortion when Anger logic is used for event positioning. A small rotation in the flood histogram is also observed when the detectors are placed in a magnetic field. We first present a general purpose automatic method for spatial distortion correction for flood histograms of PSAPD-based PET detectors when placed both inside and outside a MRI scanner. Analytical formulae derived for this scheme are based on a hybrid approach that combines desirable properties from two existing event positioning schemes. The rotation of the flood hist gram due to the magnetic field is determined iteratively and is accounted for in the scheme. We then provide implementation details of a method for crystal identification we have previously proposed and evaluate it for cases when the PET scanner both outside and in a magnetic field. In this scheme, Fourier analysis is used to generate a lower-order spatial approximation of the distortion-corrected PSAPD flood histogram, which we call the 'template'. The template is then registered to the flood histogram using a diffeomorphic iterative intensity-based warping scheme. The calculated deformation field is then applied to the segmentation of the template to obtain a segmentation of the flood histogram. A manual correction tool is also developed for exceptional cases. We present a quantitative assessment of the proposed distortion correction scheme and crystal identification method against conventional methods. Our results indicate that our proposed methods lead to a large reduction in manual labor and indeed can outinely be used for calibration and characterization studies in MRI-compatible PET scanners based on PSAPDs.
KW - PETIMRI, PSAPD, Spatial distortion correction, Crystal identification
UR - http://www.scopus.com/inward/record.url?scp=67649194596&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67649194596&partnerID=8YFLogxK
U2 - 10.1109/NSSMIC.2008.4774373
DO - 10.1109/NSSMIC.2008.4774373
M3 - Conference contribution
SN - 9781424427154
SP - 5045
EP - 5052
BT - IEEE Nuclear Science Symposium Conference Record
ER -