190 likes | 382 Views
Multi-Modality Imaging Laboratory Department of Radiology Department of Biomedical Engineering Duke University Medical Center, Durham, NC, USA. Comparison of Scintimammography and Dedicated Emission Mammotomography. Martin P. Tornai, Caryl N. Brzymialkiewicz, Spencer J. Cutler, Priti Madhav.
E N D
Multi-Modality Imaging Laboratory Department of Radiology Department of Biomedical Engineering Duke University Medical Center, Durham, NC, USA Comparison of Scintimammography and Dedicated Emission Mammotomography Martin P. Tornai, Caryl N. Brzymialkiewicz, Spencer J. Cutler, Priti Madhav Supported by NIH Grant RO1-CA96821 and DAMD 17-03-1-0558
Overview • Develop a “universal” breast phantom for emission and/or transmission imaging • Needs to be compressible for uncompressed and partial compression imaging comparisons • Needs to accommodate inserted lesions • Needs to have physical attributes similar to human torso • Make direct comparison of uncompressed breast SPECT and compressed scintimammography • Develop and compare various fillable lesion sizes • Compare different activity concentrations
Solid State Imaging Detector Detector CdZnTe Density 5.78 g/cm3 Effective Z 49 Elements 64 x 80 Crystal Dimensions 2.3 x 2.3 x 5 mm3 Pixel Size 2.5 x 2.5 mm2 FOV 16 x 20 cm2 Sensitivity 38 cts/sec/MBq Uniformity (post corr) < ±4% Energy Resolution 6.1% @ 140 keV 20.0 cm 16.0 cm 6.6 cm LumaGEM™ 3200-S (Gamma Medica Inc.)
ROR Polar Tilt, Azimuth, Prototype Emission Mammotomograph Anthropomorphic torso and breast phantoms (Radiology Support Devices, Inc.) Integrated Gamma Camera (Gamma Medica, Inc.) Radius of Rotation control (Newport Corp., Sanyo-Denki) Rotation stage and goniometer (Newport Corp.)
Fill port 3 cm f insertion port Compressible Breast Phantom & Chest Plate Fillable Volume: ~700 mL Nipple-Chest: 9 cm Medial-Lateral: 12 cm Superior-Inferior: 13 cm “Skin” thickness: 0.16 cm (Radiology Support Devices, Inc.)
Compressible Breast Phantom & Lesions Digital X-ray image Stems: 1.6 mm OD x 4.5 cm polyethylene 70 140 500 300 Lesions Volume “Diameter” (microL) (mm) 40 +/- 0.15 4.2 70 +/- 0.15 5.1 140 +/- 0.15 6.4 300 +/- 0.30 8.2 500 +/- 0.30 9.8 40 140 140 (Harvard Apparatus)
Scintimammography Acquisition Parameters 20X clinical ! Lesion Concentration 40 microCi / mL Lesion : Background Inf., 12 : 1, 7 : 1, 3 : 1 View Lateral (single view) Compression 12 cm, 9 cm, 6 cm Acquisition Time 10 min (equivalent)
9 cm 6 cm 4 cm Breast Compression 12 cm Cranio-Caudal Lateral
9cm 3 : 1 9cm 12 : 1 9cm 7 : 1 Scintimammography (Planar) Projections Compression Thickness 12 cm 9 cm 6 cm 12 : 1 7 : 1 Leaky Phantom 3 : 1
Scintimammography: Effects of Compression 12 : 1 Concentration Ratio
Scintimammography: Effects of Activity Concentration 6 cm Compression
SPECT Acquisition Parameters 20X clinical ! Lesion Concentration 40 microCi / mL Lesion : Background Ratios Inf., 12 : 1, 7 : 1, 3 : 1 Mammotomography (q = 0 – 360) Orbits: Vertical Axis of Rotation (VAOR) ROR = 6.6 cm, f = 0 deg Tilted Parallel Beam (TPB) ROR = 5.2 cm, f = 45 deg 3 Lobed Sinusoid on Hemisphere (ProjSine) ROR = 2.8 – 5.2 cm, f = 15 – 45 deg Angular Increment : 2.8 deg Acquisition Time : 10 min (equivalent) Details about orbits and sampling on POSTER # M2-269
0o 30o Camera Tilt () 60o 90o Mammotomography Orbits VAOR TPB45 ProjSine Details about orbits and sampling on POSTER # M2-269
Maximum Intensity Projection (MIP) Mammotomography Reconstructions 12 : 1 Concentration ProjSine Data Transverse Sagittal OSEM reconstruction with 5 iterations, 8 subsets, calculated attenuation correction, 3D Hann filtration with fc = 0.8*Nyquist
40 uL 300 uL 500 uL 70 uL 140 uL Mammotomography MIPs VAOR TPB45 ProjSine 12 : 1 7 : 1 3 : 1
SPECT SNR & Contrast 12 : 1 Concentration Data ROI data from OSEM reconstruction with 3 iterations, 8 subsets, calculated attenuation correction, 3D Hann filtration with fc = 0.8*Nyquist
Conclusions • Developed a compressible breast+chest phantom useful for comparative emission breast imaging with physical limitations more consistent with a human torso • Measured various lesion sizes, locations (esp. near chest wall), and activity concentrations relative to backgrounds • Compared compressed breast, planar scintimammography with uncompressed breast SPECT mammotomography • Scintimammography has limited viewable breast volume towards the anterior chest wall Under a wide range of “low noise” measurement conditions: More lesions, lesion sizes, and (3D) lesion locations can be detected (and thus quantitated) with dedicated emission mammotomography than with compressed breast scintimammography