Optimizing CT Image Quality: CARE kV

November 2011 PART 4: CARE kV ADJUSTING VOLTAGES Adjusting Voltages Without Exposure Control V Operation Fixed kV Fixed Eff. mAs Features Fixed kV Fixed Eff. mAs With CARE Dose4D With CARE Dose4D & CARE kV Fixed kV Quality Ref. mAs Ref. kV Quality Ref. mAs Fixed kV Actual kV Eff. mAs Eff. mAs CARE kV Increasing X-ray Tube Voltage (kV) Optimization of kV Ka to minimize patient dose at maintained Image Quality KB 100 kV Relative intensity 0 kVp 110 20 40 60 80 90 Photon energy (keV) 70 50 More X-rays # of X-Ray Photons 0 10 20 30 40 50 60 70 80 90 100 110 X-Ray Photon Energy (keV) More Penetration Part 4 (CARE kV) Huda 1 November 2011 Adjusting kV affects: CARE kV Requires Diagnostic Task 110 90 70 70 kV 50 Non-contrast 140 kV # of X-Ray Photons 0 10 20 30 40 50 60 70 80 90 100 110 X-Ray Photon Energy (keV) Contrast Noise Contrast enhanced + CT Angiography Quality ref mAs 210 | Ref V 120 Quality ref. mAs 210 | Ref. kV 120 Dose saving optimized for * Dose saving optimized for 1 2 3 Non-contrast: 3 5 6 7 8 9 10 11 12 Contrast enhanced: 7 CT Angiograhy: 11 CARE kV CARE kV …… Identifies task (user) Computes noise versus kV Computes lesion Computes Contrast versus kV to Noise Ratio CNR Part 4 (CARE kV) Huda 2 November 2011 CARE kV ……. kV and mAs  “Dose” CNR “Controlled” ----  Adjusting mAs Radiation dose mAs 70 100 120 140 kV adjusted 8  equalize “Optimal kV”  80 100 120 140 CNR “Lowest Dose” OPERATION . CARE Dose4D + CARE KV . No exposure control: reference kV adapted kV fixed kV quality reference mAs adapted mAs fixed mAs definition of image quality patient size topogram) tissue of interest (manual!) CARE Dose4D: fixed kV quality reference mAs adapted mAs CARE DOSe4D - CARE KV On definition of image quality patient size Off (topogram) Elf. MAS 172 KV Semi On Organ characteristic: Abdomen CTDIvol (32cm): 6.80 mGy DLP. 169,5 mGy"cm Protocol Defines CARE kV Example Quality Ref. mAs Quality ref. mAs 210 Ret kV 120 Ref. kV Lexan Dowe saving optimized for Aculon Acrylic Diagnostic Task Polyethylene Teflon Never Adjust b Water  “Individual Patient” Part 4 (CARE kV) Huda 3 November 2011 CARE Dose4D (140 kV) “Low Z” 140 kV 2.6 mGy (Soft Tissue) Qual. Ref. mAs 80 21 eff.mAs [CTDIvol 10 mGy] “High Z” WO-11. IHU (Iodinated Contrast) mAs (& CTDIvol) reduced to ~25% in small phantom CARE Dose4D + CARE kV CARE Dose4D + CARE kV Non-contrast setting: 3 CT Angiography setting: 11 140 kV 80 kV 2.7 mGy 21 eff.mAs 2.6 mGy 102 eff.mAs 140 kV 21 eff.mAs .6 mGy 80 k\ 0.94 mGy 36 eff.mAs, 8-11.1HU O0-11 THU Same “Soft Tissue” CNR Same “Iodine” CNR Similar CTDIvol CTDIvol 65% @ 80 kV FEATURES Changing kV  Changes Contrast Display Window Grouping Semi kV mode Part 4 (CARE kV) Huda 4 November 2011 Fully Assisting Scanner Technologies (FAST) Multi-Phase CT Study Without FAST Window With FAST Window  Venous Delayed Display Window Adjusted Topogram 0 Link Series  Non Co Forces “single kV” Pause Quality ref mAs 210 | Ref. kV 120 PreMonitoring Dose saving optimized for 70 Contrast 60 50 Monitoring Arterial Phase RT 10 11 12 E of all Scans: 40 20 + PV Phase 10 O 10 KV 100 120 KV 140 KK Arterial & Venous Phase (7)  100 kV CARE kV Identifies Optimum kV Monitoring Non-Contrast Phase (3) Links Arterial Phase  140 kV Series PV Phase Semi kV MODE Qualityref. mÃs 210 9| Ref KV 120 - Doce saving optimized for CARE Dose4D M CARE KV Semi Semi: CARE DOSe4D & CARE KV [Semi ] ] CARE DOS64D LI CARE KV [Semi ] ] EM. MAS 247 KV ET. MAS 93 V 120 m Organ characteristic: Abdomen Investigate CTDIvol/mAs Organ characteris le: Abdomen CTDIvol (32cm): 4.85 mGy DLP. 104.1 mGy'cm CTDivol (2cm): 6.31 moy DLP. 1356 moy"cm For Different kV 120 kV  80 kV Dose Savings/Penalties Constant CNR Dose  25% Part 4 (CARE kV) Huda 5 November 2011 Follow up Study REQUIRES CARE kV SUMMARY Same kV as Initial Scan FAST CARE Fully Assisting Scanner Technologies Combined Applications to Reduce Exposure CARE DOS94D M CARE KV Sem . FAST Spine CARE KV . FAST Adjust CARE Child Eff. mAS KV 120 . FAST Planning 210 CARE Profile · FAST Cardio Wizard . CARE Dashboard 70 · FAST Scan Assistant . CARE Dose4D Organ characteristic: Abdomen 80 CTDIvol (32cm): 14.19 mGy DLP 100 120 140 Operator Selects and Fixes kV CARE kV + CARE Dose4D Operation Identifies Optimal kV Quaityret mas 210 2 Ret 120 - Requires Dose saving optmized for Diagnostic X -- Selects Eff. mAs Task radiation dose  Dose image quality/CNR Maintains Image O CNR Quality (CNR) > Features FAST Next Window CLINICAL TECHNIQUES Monitoring Grouping/ Arterial Phase PV Phase Linking CARE Dose4D - CARE KV On CARE DOROAD - CARE KV Sem 2TS Off Semi kV Eff MAS 172 KV Semi On EF. MAs 120 -J Orpan characteristic: Abdomen mode Organ characteristic Abdomen CTDIol (32cm) 6.80 mGy DLP. 169.5 mGy*cm Part 4 (CARE kV) Huda 6