1. SIMULTANEOUS Tl-201/Tc-99m IMAGING FOR MYOCARDIAL PERFUSION Andries van Aswegen Department of Nuclear Medicine Royal Brompton Hospital

2. ADVANTAGES One acquisition for stress and rest studies Rest and stress images perfectly aligned - attenuation, positioning & motion the same Enhances patient throughput

3. What has been done so far? Hannequin et al – use spectral deconvolution technique; photon energy recovery; 7 Tl-201 windows & 3 Tc-99m windows De Jong et al – combined rotation-based Monte Carlo & convolution-based forced detection; RMC generates 3D scatter map; CFD incorporates detector blurring and Pb X-rays Is there a simpler method? Ogawa et al – triple energy window (TEW) method; requires at least 4 energy windows

4. Tl-201TEW PATIENT STUDY

5. Tl-201 decay data Decay by EC  9 167 keV (10% yield) K  X-rays 69 – 71 keV K  X-rays 80 keV [Pb X-rays 88 keV]

6. TRIPLE ENERGY WINDOW METHOD

7. TEW ENERGY WINDOWS Tc-99m:140 keV20%126  154 keV Tl-201 main:72 keV35%59  85 keV Upper window:96 keV8%92  100 keV Lower window:52 keV10%49  55 keV

9. CARDIAC PHANTOM Tl-201 image (true) TEW image (no bkgd) TEW (liver bkgd) TEW (liver, body bkgd)

10. SEGMENTAL ANALYSIS (Tl & TEW) 1 2 3 4 5 6 7 89 Ant Lat Inf Sep Seg 1 2 3 4 5 6 7 8 9 Tl-201 56 39 57 71 79 81 96 100 TEW 52 43 55 72 81 93 100 TEW Liv 55 44 57 75 85 82 80 96 100 TEW LivBod 60 41 53 67 84 79 82 100

11. CARDIAC PHANTOM Tc-99m image (no bkgd) Tc-99m (liver bkgd) Tc-99m (liver, body bkgd)

12. SEGMENTAL ANALYSIS (TEW & Tc) 1 2 3 4 5 6 7 89 Ant Lat Inf Sep Seg 1 2 3 4 5 6 7 8 9 TEW 52 43 55 72 81 93 100 Tc-99m 57 40 58 77 80 76 94 100 Tc Liv 61 41 61 79 89 86 76 94 100 Tc LivBod 51 64 84 82 83 85 98 100