Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI

Christof Knoess, Ronald Boellaard, Mark Lenox, Stefan Vollmar, Mike Casey, Guenter Fluegge, Adriaan Lammertsma, Klaus Wienhard, Wolf Dieter Heiss

Research output: Contribution to conferencePaperAcademic

Abstract

The High Resolution Research Tomograph (HRRT) is the first clinical LSO scanner with Depth of Interaction (DOT) capability. At the moment two HRRT's exist: one is located at the Max-Planck-Institute in Cologne and is equipped with two 7.5 mm thick crystal layers and DOI (HRRT-D); the second HRRT is located at the VUmc in Amsterdam with a single crystal layer (HRRT-S). This constellation allows evaluation of scanner characteristics with and without DOI. The effects of DOI on resolution, sensitivity, scatter fraction (SF) and noise equivalent count (NEC) rates were studied. These characteristics were measured according to the NEMA NU2-1994 or 2001 standards. Emission scans were acquired in 64 bit list mode. For HRRT-D emission data were sorted into files with coincidences between the layers nearest to the center of the scanner only and into files with all layer combinations providing DOI. Resolution data were analyzed with different data compressions (span 3 and 9) and for FORE+2D-HOSP and 3D-OSEM. Different scatter fractions between both scanners were observed for lower level discriminator values (llds) of higher energy. NEC rates were about 3 times higher for HRRT-D. Best resolution values of 2.0 mm FWHM at 0 cm radial offset from the center and 2.5 mm FWHM at 10 cm radial offset were found using span 3 and 3D-OSEM for HRRT-S. Equal values were found for HRRT-D using DOI. For span 9 data and FORE+2D-HOSP the axial resolution decreased at off center locations to 4 mm FWHM or more. The higher NECR of HRRT-D compared with HRRT-S is explained by the higher sensitivity, obtained with the additional crystal layer. Differences in scatter fractions might be explained by the difference in crystal energy spectra of both scanners. Comparison of resolution data of both scanners showed that high spatial resolution was preserved with DOI.

Original languageEnglish
Pages1447-1451
Number of pages5
Publication statusPublished - 1 Dec 2002
Event2002 IEEE Nuclear Science Symposium Conference Record - Norfolk, VA, United States
Duration: 10 Nov 200216 Nov 2002

Conference

Conference2002 IEEE Nuclear Science Symposium Conference Record
CountryUnited States
CityNorfolk, VA
Period10/11/200216/11/2002

Cite this

Knoess, C., Boellaard, R., Lenox, M., Vollmar, S., Casey, M., Fluegge, G., ... Heiss, W. D. (2002). Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI. 1447-1451. Paper presented at 2002 IEEE Nuclear Science Symposium Conference Record, Norfolk, VA, United States.
Knoess, Christof ; Boellaard, Ronald ; Lenox, Mark ; Vollmar, Stefan ; Casey, Mike ; Fluegge, Guenter ; Lammertsma, Adriaan ; Wienhard, Klaus ; Heiss, Wolf Dieter. / Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI. Paper presented at 2002 IEEE Nuclear Science Symposium Conference Record, Norfolk, VA, United States.5 p.
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abstract = "The High Resolution Research Tomograph (HRRT) is the first clinical LSO scanner with Depth of Interaction (DOT) capability. At the moment two HRRT's exist: one is located at the Max-Planck-Institute in Cologne and is equipped with two 7.5 mm thick crystal layers and DOI (HRRT-D); the second HRRT is located at the VUmc in Amsterdam with a single crystal layer (HRRT-S). This constellation allows evaluation of scanner characteristics with and without DOI. The effects of DOI on resolution, sensitivity, scatter fraction (SF) and noise equivalent count (NEC) rates were studied. These characteristics were measured according to the NEMA NU2-1994 or 2001 standards. Emission scans were acquired in 64 bit list mode. For HRRT-D emission data were sorted into files with coincidences between the layers nearest to the center of the scanner only and into files with all layer combinations providing DOI. Resolution data were analyzed with different data compressions (span 3 and 9) and for FORE+2D-HOSP and 3D-OSEM. Different scatter fractions between both scanners were observed for lower level discriminator values (llds) of higher energy. NEC rates were about 3 times higher for HRRT-D. Best resolution values of 2.0 mm FWHM at 0 cm radial offset from the center and 2.5 mm FWHM at 10 cm radial offset were found using span 3 and 3D-OSEM for HRRT-S. Equal values were found for HRRT-D using DOI. For span 9 data and FORE+2D-HOSP the axial resolution decreased at off center locations to 4 mm FWHM or more. The higher NECR of HRRT-D compared with HRRT-S is explained by the higher sensitivity, obtained with the additional crystal layer. Differences in scatter fractions might be explained by the difference in crystal energy spectra of both scanners. Comparison of resolution data of both scanners showed that high spatial resolution was preserved with DOI.",
author = "Christof Knoess and Ronald Boellaard and Mark Lenox and Stefan Vollmar and Mike Casey and Guenter Fluegge and Adriaan Lammertsma and Klaus Wienhard and Heiss, {Wolf Dieter}",
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Knoess, C, Boellaard, R, Lenox, M, Vollmar, S, Casey, M, Fluegge, G, Lammertsma, A, Wienhard, K & Heiss, WD 2002, 'Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI' Paper presented at 2002 IEEE Nuclear Science Symposium Conference Record, Norfolk, VA, United States, 10/11/2002 - 16/11/2002, pp. 1447-1451.

Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI. / Knoess, Christof; Boellaard, Ronald; Lenox, Mark; Vollmar, Stefan; Casey, Mike; Fluegge, Guenter; Lammertsma, Adriaan; Wienhard, Klaus; Heiss, Wolf Dieter.

2002. 1447-1451 Paper presented at 2002 IEEE Nuclear Science Symposium Conference Record, Norfolk, VA, United States.

Research output: Contribution to conferencePaperAcademic

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AU - Knoess, Christof

AU - Boellaard, Ronald

AU - Lenox, Mark

AU - Vollmar, Stefan

AU - Casey, Mike

AU - Fluegge, Guenter

AU - Lammertsma, Adriaan

AU - Wienhard, Klaus

AU - Heiss, Wolf Dieter

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Knoess C, Boellaard R, Lenox M, Vollmar S, Casey M, Fluegge G et al. Evaluation of the Depth of Interaction (DOI) for the High Resolution Research Tomograph (HRRT) - A comparison between scanners with and without DOI. 2002. Paper presented at 2002 IEEE Nuclear Science Symposium Conference Record, Norfolk, VA, United States.