Abstract
We explore two depth of interaction (DOI) capable detectors with a high effective packing fraction to be used for the PET portion of a next generation cylindrical pendant breast PET/CT scanner. The proposed dual-readout detectors consist of an unpolished (14 × 14) array of (1.5 × 1.5 × 20) mm3 LSO crystals coupled to a position sensitive-PMT (PSPMT) at the back end for position sensing and either (A) a (2 × 2) matrix of avalanche photodiodes (APDs) or (B) a single large APD at the front end for measuring DOI. Increased effective packing fraction is achieved by choosing the APDs such that the total front surface contact area of the APD matrix or the single large APD approximately matches both the contact area of the crystal array and the active area of the PSPMT. This results in reduced dead space between adjacent detectors when placed in a cylindrical scanner geometry. We propose to recover DOI for the crystals that are partially occluded due to the inactive area of the APD by using the optical crosstalk from neighboring crystals. We conducted preliminary studies utilizing five prototype modules: two of which used a (9 × 9) array of (1.5 × 1.5 × 20) mm3 LSO crystals, and three that used a (14 × 14) LSO array of (1.5 × 1.5 × 30) mm3 crystals. The readout was performed either by a (8 × 8) mm3, (14 × 14) mm3 or a (28 × 28) mm 3 position sensitive-APD (PSAPD) at the front end and a PSPMT at the rear end. At room temperature, the average energy and DOI resolutions degraded only by <2% and <0.3 mm respectively for edge crystals compared to the center crystals for all PSAPDs. The energy resolution and the DOI resolution for the detector design with readout (A) was estimated to be 14.2% and 4.0 mm, and that for the design with readout (B) was estimated at 14.7% and 4.4 mm. After cooling to 10 °C, the performance of the second design was close to that of the first design. We conclude that a dedicated cylindrical breast PET/CT scanner could be operated with either of the proposed DOI detector schemes, thus improving packing fraction, and hence, sensitivity and NEC. The two designs have different advantages and drawbacks: the first design performs well at room temperature, however, the readout is complex, while the second design has a simpler readout scheme but requires a cooling system for it to achieve optimal performance.
| Original language | English (US) |
|---|---|
| Article number | 4545080 |
| Pages (from-to) | 853-861 |
| Number of pages | 9 |
| Journal | IEEE Transactions on Nuclear Science |
| Volume | 55 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jun 2008 |
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Keywords
- Breast imaging
- Dedicated
- Depth of interaction
- High packing fraction
- PET/CT
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Nuclear Energy and Engineering
Cite this
PSPMT/APD hybrid DOI detectors for the PET component of a dedicated breast pET/CT system - A feasibility study. / Chaudhari, Abhijit; Yang, Yongfeng; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Cherry, Simon R; Badawi, Ramsey D.
In: IEEE Transactions on Nuclear Science, Vol. 55, No. 3, 4545080, 06.2008, p. 853-861.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - PSPMT/APD hybrid DOI detectors for the PET component of a dedicated breast pET/CT system - A feasibility study
AU - Chaudhari, Abhijit
AU - Yang, Yongfeng
AU - Farrell, Richard
AU - Dokhale, Purushottam A.
AU - Shah, Kanai S.
AU - Cherry, Simon R
AU - Badawi, Ramsey D
PY - 2008/6
Y1 - 2008/6
N2 - We explore two depth of interaction (DOI) capable detectors with a high effective packing fraction to be used for the PET portion of a next generation cylindrical pendant breast PET/CT scanner. The proposed dual-readout detectors consist of an unpolished (14 × 14) array of (1.5 × 1.5 × 20) mm3 LSO crystals coupled to a position sensitive-PMT (PSPMT) at the back end for position sensing and either (A) a (2 × 2) matrix of avalanche photodiodes (APDs) or (B) a single large APD at the front end for measuring DOI. Increased effective packing fraction is achieved by choosing the APDs such that the total front surface contact area of the APD matrix or the single large APD approximately matches both the contact area of the crystal array and the active area of the PSPMT. This results in reduced dead space between adjacent detectors when placed in a cylindrical scanner geometry. We propose to recover DOI for the crystals that are partially occluded due to the inactive area of the APD by using the optical crosstalk from neighboring crystals. We conducted preliminary studies utilizing five prototype modules: two of which used a (9 × 9) array of (1.5 × 1.5 × 20) mm3 LSO crystals, and three that used a (14 × 14) LSO array of (1.5 × 1.5 × 30) mm3 crystals. The readout was performed either by a (8 × 8) mm3, (14 × 14) mm3 or a (28 × 28) mm 3 position sensitive-APD (PSAPD) at the front end and a PSPMT at the rear end. At room temperature, the average energy and DOI resolutions degraded only by <2% and <0.3 mm respectively for edge crystals compared to the center crystals for all PSAPDs. The energy resolution and the DOI resolution for the detector design with readout (A) was estimated to be 14.2% and 4.0 mm, and that for the design with readout (B) was estimated at 14.7% and 4.4 mm. After cooling to 10 °C, the performance of the second design was close to that of the first design. We conclude that a dedicated cylindrical breast PET/CT scanner could be operated with either of the proposed DOI detector schemes, thus improving packing fraction, and hence, sensitivity and NEC. The two designs have different advantages and drawbacks: the first design performs well at room temperature, however, the readout is complex, while the second design has a simpler readout scheme but requires a cooling system for it to achieve optimal performance.
AB - We explore two depth of interaction (DOI) capable detectors with a high effective packing fraction to be used for the PET portion of a next generation cylindrical pendant breast PET/CT scanner. The proposed dual-readout detectors consist of an unpolished (14 × 14) array of (1.5 × 1.5 × 20) mm3 LSO crystals coupled to a position sensitive-PMT (PSPMT) at the back end for position sensing and either (A) a (2 × 2) matrix of avalanche photodiodes (APDs) or (B) a single large APD at the front end for measuring DOI. Increased effective packing fraction is achieved by choosing the APDs such that the total front surface contact area of the APD matrix or the single large APD approximately matches both the contact area of the crystal array and the active area of the PSPMT. This results in reduced dead space between adjacent detectors when placed in a cylindrical scanner geometry. We propose to recover DOI for the crystals that are partially occluded due to the inactive area of the APD by using the optical crosstalk from neighboring crystals. We conducted preliminary studies utilizing five prototype modules: two of which used a (9 × 9) array of (1.5 × 1.5 × 20) mm3 LSO crystals, and three that used a (14 × 14) LSO array of (1.5 × 1.5 × 30) mm3 crystals. The readout was performed either by a (8 × 8) mm3, (14 × 14) mm3 or a (28 × 28) mm 3 position sensitive-APD (PSAPD) at the front end and a PSPMT at the rear end. At room temperature, the average energy and DOI resolutions degraded only by <2% and <0.3 mm respectively for edge crystals compared to the center crystals for all PSAPDs. The energy resolution and the DOI resolution for the detector design with readout (A) was estimated to be 14.2% and 4.0 mm, and that for the design with readout (B) was estimated at 14.7% and 4.4 mm. After cooling to 10 °C, the performance of the second design was close to that of the first design. We conclude that a dedicated cylindrical breast PET/CT scanner could be operated with either of the proposed DOI detector schemes, thus improving packing fraction, and hence, sensitivity and NEC. The two designs have different advantages and drawbacks: the first design performs well at room temperature, however, the readout is complex, while the second design has a simpler readout scheme but requires a cooling system for it to achieve optimal performance.
KW - Breast imaging
KW - Dedicated
KW - Depth of interaction
KW - High packing fraction
KW - PET/CT
UR - http://www.scopus.com/inward/record.url?scp=45849101323&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=45849101323&partnerID=8YFLogxK
U2 - 10.1109/TNS.2008.924073
DO - 10.1109/TNS.2008.924073
M3 - Article
AN - SCOPUS:45849101323
VL - 55
SP - 853
EP - 861
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
SN - 0018-9499
IS - 3
M1 - 4545080
ER -