7/21/2014 “Partners in Solution” session Philips CT Dose Optimization tools and Advanced Reconstruction Tsvi Katchalski Philips July 24, 2014 1 Philips Research - Hamburg Confidential Content (I) Dose Reduction and Dose Optimization Technologies • • • • • • Dose Right and Tube Current Modulation (Dose Right, Z-DOM, 3D-DOM) Special Acquisition Modes (Cardiac Dose Right, Prospective gating) Beam Filtration and Beam Shapers Eclipse Collimator and Clear Ray Collimator NanoPanel Elite Detector NEMA XR-25 – Dose check – Dose structured reporting (II) Advanced Reconstruction Technology • iDose4 • IMR (Iterative Model) 2 Philips Research - Hamburg Confidential PART (I) (I) Dose Reduction and Dose Optimization Technologies • • • • • • Dose Right and Tube Current Modulation (Dose Right, Z-DOM, 3D-DOM Special Modulation Modes (Cardiac Dose Right, Prospective gating) Beam Filtration and Beam Shapers Eclipse Collimator and Clear Ray Collimator NanoPanel Elite Detector NEMA XR-25 – Dose check – Dose structured reporting (II) Advanced Reconstruction Technology • iDose4 • IMR (Iterative Model) 3 Philips Research - Hamburg Confidential 1 7/21/2014 Dose Right and Tube Current Modulation Dose Right Index Consistent IQ for Different Patient Size Dose Right Index + Current Modulation Consistent IQ for Different Patients and at Different Z-Locations DoseRight recommendation: 389mAs 4 Philips Research - Hamburg DoseRight recommendation: 240mAs Confidential Dose Right Index – Definition (by Reference) DRI=24 200 mAs @120 kV @ average patient size (29 cm) Dose Right – How Does it Work Averages patient size is calculated from the surview Avg. mAs for the patient is calculated according to the DRI Patient size is compared to the EC Reference size Exponential Adaptation to Patient size 1000 900 Current x Time [mAs] 800 700 600 500 400 300 200 100 0 0 10 20 30 40 50 Average Size [cm] 5 Philips Research - Hamburg Confidential Increase and Decrease in DRI (Dose Right Index) - Adults 6 cm: +100% (doubled) mAs 25cm 29cm 35cm 18 71 102 202 19 80 114 226 20 90 128 254 21 101 143 284 22 113 160 317 23 127 179 355 24 142 200 400 1 DRI: 25 159 224 443 +12% mAs 26 178 250 497 DRI … 6 DRI: +100% mAs … 6 Philips Research - Hamburg Confidential 6 2 7/21/2014 Z- Dose Modulation (Z-DOM) Consistent IQ Along Patient Liver Detection Head Detection 500 mAs 400 300 200 100 0 0 5 10 15 20 25 Z-position 7 Philips Research - Hamburg Confidential 3D- Dose Modulation (3D-DOM) Reduction of Streak Artifacts Improve Noise Uniformity 8 Philips Research - Hamburg Confidential 3D- Dose Modulation vs. Z-DOM - Reduction of Streak Artifacts - Improve Noise Uniformity 9 Philips Research - Hamburg Confidential 3 7/21/2014 Automatic Pitch/Rotation Time Algorithm Basic equations: 𝑠𝑐𝑎𝑛 𝑡𝑖𝑚𝑒 = 𝑏𝑒𝑑 𝑠𝑝𝑒𝑒𝑑 = 𝑚𝐴𝑠 = mAs Philips Research - Hamburg 𝑝𝑖𝑡𝑐ℎ × 𝑐𝑜𝑙𝑙𝑖𝑚𝑎𝑡𝑖𝑜𝑛 𝑟𝑜𝑡𝑎𝑡𝑖𝑜𝑛 𝑡𝑖𝑚𝑒 𝑚𝐴 × 𝑟𝑜𝑡𝑎𝑡𝑖𝑜𝑛 𝑡𝑖𝑚𝑒 𝑝𝑖𝑡𝑐ℎ Pitch / rotation time Bed speed Tube current 10 𝑠𝑐𝑎𝑛 𝑙𝑒𝑛𝑔𝑡ℎ 𝑏𝑒𝑑 𝑠𝑝𝑒𝑒𝑑 Confidential Special Modulation Modes - Cardiac Heart Cycle – The Heart is in Constant Motion General motion profile: • Relaxation: Heart is filled with blood. • Contraction: Heart ‘pushes’ blood to the body/Lungs “Quiet phases”: Phases with relatively less motion • End systolic (“40%”): • End diastolic (“75%”): Relaxation Expansion Relaxation Contraction Diastole Systole “0%” 11 Philips Research - Hamburg “40%” “75%” “100%” Confidential Cardiac Cycles Reconstructing at Different Phases – ECG Gated Cardiac Phase 20 12 Philips Research - Hamburg 35 75 Confidential 4 7/21/2014 Special Modulation Modes Cardiac Retrospective • ECG triggered dose modulation in Helical/Spiral scans Cardiac DoseRight - Prospective Z 100 % 20 % 13 Philips Research - Hamburg 57 Confidential 34 Special Modulation Modes Cardiac Step and Shoot – Prospective Gating • Low dose (3–5 mSv) diagnostic scan – Dose reduction up to 80% compared to standard retrospectively-gated spiral scans – Image quality comparable to that of standard retrospectivelygated spiral scans • 3D axial cone beam reconstruction algorithm • Real-time arrhythmia handling algorithms 14 Philips Research - Hamburg Confidential Special Modulation Modes Dose Reduction (%) Dose Reduction from ECG Dose Modulation – Dependency on HR 90 80 70 60 50 40 30 20 10 0 60 bpm 70 bpm 80 bpm 90 bpm 100 bpm S&SC Compared to ECG-gated spiral scans without dose modulation Klass O, Walker MJ, et al, Eur Rad 2008 15 Philips Research - Hamburg Confidential 5 7/21/2014 Beam Filtration and Beam Shapers InteliBeam Filters SmartShape Wedge (Bowtie) Filters - - 16 Philips Research - Hamburg Filtration is optimized to increase Low Contrast and reduce Skin Dose and is done per protocol Three filtration modes: “Half”/”Full”/”Off-center enabled” Confidential Eclipse Collimator and Clear Ray Collimator Helical Dynamic Collimation to Reduce Over Scanning Walker MJ, Olszewski ME, Desai MY, et al, Intl Journal of Cardiovasc Imaging, 2009 17 Philips Research - Hamburg Confidential Eclipse Collimator and Clear Ray Collimator 2D Anti Scatter Grid 18 Philips Research - Hamburg Confidential 6 7/21/2014 Clear Ray Scatter and Beam Hardening Correction - 19 Philips Research - Hamburg Monte Carlo based scatter estimation Analytical Beam Hardening Correction Scatter correction is proportional to patient size Confidential NanoPanel Elite New Tile Detector Scintillator – – – – IGOS (Gd2O2S) High Quality Ceramic Scintillator Fast Response High Light Output Low Cross-Talk PDA (Photo Diode Array) – – – – Back Illuminated Using Thin and High purity Silicon High Quantum efficiency. High Shunt Resistance Low Cross-talk ASIC – Very Low Noise – Improved linearity over all the dynamic range – Front End Electronics with 256 Channels 20 Philips Research - Hamburg Confidential PART (II) (I) Dose Reduction and Dose Optimization Technologies • • • • • Dose Right and Tube Current Modulation (Dose Right, Z-DOM, 3D-DOM Special Acquisition Modes (Cardiac Dose Right, Prospective gating) Beam Filtration and Beam Shapers Eclipse Collimator and Clear Ray Collimator NanoPanel Elite Detector (II) Advanced Reconstruction Technology • iDose4 • IMR (Iterative Model) 21 Philips Research - Hamburg Confidential 7 7/21/2014 iterative reconstruction technique: How does it work? iDose advanced reconstruction How it works iDose uses the raw data output from the NanoPanel detector to determine and remove noise while keeping structure intact 22 Philips Research - Hamburg Confidential iDose – Mode of Operation Noise Reduction – Reduce noise according to iDose Level selection – For each protocol the achievable iDose Level were determined – No degradation in Resolution and Low Contrast (Tolerance: 10% in MTF10% and 1mm in Low Contrast) High mA Compensating increase in noise (noise reduction %) 11 % 16 % 23 % 29 % 37 % 45 % 55 % IQ Improvements – Keep the Dose Level the same and improve spatial resolution and Low Contrast Hardware Enabler – RapidView IR, Next Generation Intel Multi-Core Processors – Up to 20 Images/sec 23 Philips Research - Hamburg Confidential Comparison Full Dose / 50% Dose Reduction + iDose Full Dose (250mAs) FBP Follow up with 50% Dose Reduction 50% Dose (125mAs) FBP 24 Philips Research - Hamburg Confidential 50% Dose (125mAs) iDose Courtesy TU Munich, Germany Philips Healthcare / Clinical Science & Application CT EMEA, June 6, 2008 2 4 8 7/21/2014 Comparison Full Dose / 70% Dose Reduction + iDose 120 kV, 100 mAs (6.6 mGy)/ 80 kV, 100 mAs (1.9 mGy) 70% Dose Reduction Full Dose (6.6mGy) - FBP 25 Philips Research - Hamburg Confidential 70% Dose Reduction (1.9mGy) - iDose Courtesy TU Munich, Germany Philips Healthcare / Clinical Science & Application CT EMEA, June 6, 2008 2 5 Improving Image Quality: Artifact Reduction 120kV, 70mAs, 6.4mGy, Prospective Gated Aortic CTA (Step & Shoot Complete) FBP 26 Philips Research - Hamburg Confidential iDose Courtesy Cleveland Clinic,2USA Philips Healthcare / Clinical Science & Application CT EMEA, June 6, 2008 6 Improving image quality in inherently noisy acquisitions 120kV, 280 mAs, 22.9mGy, Prospective Gated Cardiac CTA (Step & Shoot Cardiac) FBP 27 Philips Research - Hamburg Confidential iDose Philips Healthcare / Clinical Science & Application CT EMEA, June 6, 2008 Courtesy OHSU, USA 2 7 9 7/21/2014 Knowledge-Based Iterative Reconstruction Technique Name 28 Philips Research - Hamburg Confidential Knowledge-Based Iterative Reconstruction What makes this possible Fast and compact next-gen computing devices using GPU (under 3min for most protocols) Integrated Workflow User has flexibility as to the final result. Body Soft Tissue Routine Sharp Plus 29 Philips Research - Hamburg Confidential Performance Evaluation Low Contrast Detectability A measure of a person’s ability to perform a particular task: The determination of a Low Contrast object – Is influenced by all Physics IQ metrics (Noise, Resolution, Uniformity and CT number) – A statistical approach is needed – Human observer study, 4 Alternative Forced Choice (4AFC) Study was used Test Test4242out outofof100 100 30 Philips Research - Hamburg Test Test 57 57 out out of of 100 100 Test 73 out of 100 Test Test 77 77 out out of of 100 100 Test Test94 94out outofof100 100 Confidential 10 7/21/2014 Improve low-contrast detectability Revealing subtle differences 2.5 - 3.6x Low-contrast Detectability Index 4 Low-contrast Detectability Index* 3 3.9 2 1 1.4 0 Standard Reconstruction Standard Reconstruction IMR 31 * Low-contrast detectability was assessed using 4-AFC test on a reference abdomen protocol, tested on the MITA CT IQ phantom. Data on file. High resolution Imaging Revealing fine detail Standard Resolution MTF Measurements 100 FBP (Std Filter) 80 FBP (Sharp Filter) Gain (%) 60 IMR (High-res setting) 40 20 0 0 2.5 5 7.5 10 12.5 Frequency (lp/cm) 32 BODY GGO visualized on Chest CT with IMR Chest X-Ray 0.05 mSv Standard Reconstruction 80 kVp, 10 mAs, 0.2 mGy, 0.11 mSv 33 Courtesy: UCL, Belgium 11 7/21/2014 NEURO 71 year old man with hemorrhagic lesions not seen on FBP 1.0 mm slice thickness 3.0 mm slice thickness Standard Reconstruction Standard Reconstruction 1.0 mm slice thickness 120 kVp, 300 mAs, 14.3 mGy, 1.8 mSv, < 2 min recon time 34 Courtesy: UCL, Belgium Non-calcified plaque visualization FBP iDose 4 IMR L3 Mixed plaque in LM / LAD in severe obese female : 130kg, 170cm, BMI 45 Step&Shoot scan ! Max tube settings 120kV, 300mAs 12 7/21/2014 FBP iDose Excessive noise hinders segmentation IMR L3 Pre-TAVI assessment Entire ECG Gated Aorta with ONLY 40cc’s of IV contrast 20cc @2cc/s + 20cc @ 1cc/s Semmelweis Univ. Budapest Video: Maimondes Medical Center https://www.youtube.com/watch?v=X1Uk9Jvbut0 TAVI scan with only 40cc of contrast 13 7/21/2014 TAVI ISP6, annular plane TAVI ISP6, all planes TAVI ISP6, angle prediction 14 7/21/2014 Acknowledgements - Scott Smith Richard Thompson Yoad Yagil Igor Uman Elazar Gerland Shmuel Glasberg Ami Altman Amar Dhanantwari Dhruv Mehta Tom Morton Mani Vembar Galit Kafri Naama Cohen-Dahan Andrei Feldam Mani Vembar 43 Philips Research - Hamburg Confidential 44 Philips Research - Hamburg Confidential 15
© Copyright 2024 ExpyDoc
