Initial characterization of a dedicated breast PET/CT scanner during human imaging.
We have constructed a dedicated breast PET/CT scanner capable of high-resolution functional and anatomic imaging. Here, we present an initial characterization of scanner performance during patient imaging.


METHODS
The system consisted of a lutetium oxyorthosilicate-based dual-planar head PET camera (crystal size, 3 x 3 x 20 mm) and 768-slice cone-beam CT. The position of the PET heads (separation and height) could be adjusted for varying breast dimensions. For scanning, the patient lay prone on a specialized bed and inserted a single pendent breast through an aperture in the table top. Compression of the breast as used in mammography is not required. PET and CT systems rotate in the coronal plane underneath the patient sequentially to collect fully tomographic datasets. PET images were reconstructed with the fully 3-dimensional maximum a posteriori method, and CT images were reconstructed with the Feldkamp algorithm, then spatially registered and fused for display. Phantom scans were obtained to assess the registration accuracy between PET and CT images and the influence of PET electronics and activity on CT image quality. We imaged 4 women with mammographic findings highly suggestive of breast cancer (breast imaging reporting and data system, category 5) in an ongoing clinical trial. Patients were injected with (18)F-FDG and imaged for 12.5 min per breast. From patient data, noise-equivalent counting rates and the singles-to-trues ratio (a surrogate for the randoms fraction) were calculated.


RESULTS
The average registration error between PET and CT images was 0.18 mm. PET electronics and activity did not significantly affect CT image quality. For the patient trial, biopsy-confirmed cancers were visualized on dedicated breast PET/CT on all patient scans, including the detection of ductal carcinoma in situ in 1 case. The singles-to-trues ratio was found to be inversely correlated with breast volume in the field of view, suggesting that larger breasts trend toward increased noise-equivalent counting rates for all other things equal.


CONCLUSIONS
Scanning of the uncompressed breast with dedicated breast PET/CT can accurately visualize suspected lesions in 3 dimensions.
Bowen
Spencer L
SL
Department of Biomedical Engineering, UC Davis, Davis, California, USA. slbowen@ucdavis.edu
Wu
Yibao
Y
Chaudhari
Abhijit J
AJ
Fu
Lin
L
Packard
Nathan J
NJ
Burkett
George W
GW
Yang
Kai
K
Lindfors
Karen K
KK
Shelton
David K
DK
Hagge
Rosalie
R
Borowsky
Alexander D
AD
Martinez
Steve R
SR
Qi
Jinyi
J
Boone
John M
JM
Cherry
Simon R
SR
Badawi
Ramsey D
RD
D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*
J Mammary Gland Biol Neoplasia. 2006 Apr;11(2):103-11
17053979
Phys Med Biol. 1998 Apr;43(4):1001-13
9572523
Ann Oncol. 2008 Jul;19(7):1249-1254
18356138
Phys Med Biol. 2008 Feb 7;53(3):637-53
18199907
Med Phys. 2007 Feb;34(2):689-702
17388187
Med Phys. 2004 Feb;31(2):226-35
15000608
J Nucl Med. 2000 Nov;41(11):1851-8
11079494
Behav Neurol. 2000;12(4):191-200
11568431
Phys Med Biol. 2009 Jul 7;54(13):4273-87
19531852
Cancer. 2006 Dec 1;107(11):2545-51
17063499
J Clin Oncol. 2006 Dec 1;24(34):5366-72
17088570
J Nucl Med. 2004 Oct;45(10):1734-42
15471842
Med Phys. 2005 Dec;32(12):3767-76
16475776
JAMA. 2004 Jan 28;291(4):442-50
14747501
Phys Med Biol. 2004 Oct 7;49(19):4543-61
15552416
Radiology. 2007 Feb;242(2):360-85
17255408
Med Phys. 1999 Nov;26(11):2223-30
10587202
Radiology. 2008 Mar;246(3):725-33
18195383
J Nucl Med. 2008 Mar;49(3):471-9
18287272
Phys Med Biol. 2002 Aug 7;47(15):2759-71
12200937
Med Phys. 2007 Jan;34(1):275-81
17278513
J Nucl Med. 2005 Nov;46(11):1825-34
16269596
Breast Cancer Res Treat. 2006 Aug;98(3):267-74
16555126
Breast J. 2006 Jul-Aug;12(4):309-23
16848840
Med Phys. 2000 Jul;27(7):1535-43
10947256
J Clin Oncol. 2000 Oct 15;18(20):3495-502
11032590
Eur J Nucl Med Mol Imaging. 2006 Mar;33(3):254-62
16258765
Radiology. 2005 Feb;234(2):527-34
15671006