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Impact of Optimization in Newer Technologies

Impact of Optimization in Newer Technologies. L 8.2. Educational Objectives. What benefit of digital flat panel technology be expected on patient dose How to translate this into practice Experience with optimisation.

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Impact of Optimization in Newer Technologies

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  1. Impact of Optimization in Newer Technologies L 8.2

  2. Educational Objectives • What benefit of digital flat panel technology be expected on patient dose • How to translate this into practice • Experience with optimisation Lecture 8.2: Impact of optimization in newer technologies

  3. Anticipated per-frame dose reduction with Digital Flat Panel technology is 30% Lecture 8.2: Impact of optimization in newer technologies

  4. 1 3,000 400 400,000 2,400 Video Signal Video Camera Readout Electronics Electrons CCD or PUT Motorized Iris Light Output screen Digital Data Electrons Read Out Electronics Photo-cathode Image Intensifier Electrons Light Amorphous Silicon Panel (Photodiode/Transistor Array) DETECTOR Cesium Iodide (CsI) Light Cesium Iodide (CsI) Particles # Photons Photons Lecture 8.2: Impact of optimization in newer technologies

  5. diagnostic and interventional activityUdine,years 1990-2002 Philips Integris 3000 (1995) Philips OM 200 (1983) performed by 3 interventionalists except in 1998 Lecture 8.2: Impact of optimization in newer technologies

  6. Innova 2000 at Udine Center • activity started • 04/12/2002 • Jan.-Oct. 2003 • 1421 procedures (79% of total) • 1019 diagnostic • 402 PCI Lecture 8.2: Impact of optimization in newer technologies

  7. 1000 1000 1000 S1 S2 Dose Area Product • Dose in a plane (or exposure, or air-KERMA) decreases as the inverse square of the distance between this plane and the source (focal spot) • The area of the intersection of the beam with a plane increases as the square of the distance between this plane and the source (focal spot) • The product of Dose times Area is therefore independent from the distance to the source; • This Dose.Area product (DAP) can be measured by an ionization chamber, provided the beam is fully contained by the chamber d1 D1 d2 D2 d3 D3 S3 Lecture 8.2: Impact of optimization in newer technologies

  8. comparison of Philips H 3000 and Innova 2000 in PCI characteristics of patients H 3000: 588 pts, 90% of tot. treated in the year 2002 Innova: 274 pts, 67% of tot. treated between Jan-Oct 2003 diseased vessels (%) Lecture 8.2: Impact of optimization in newer technologies

  9. comparison of Philips H 3000 and Innova 2000 in PCI characteristics of procedures & lesions (1) % Lecture 8.2: Impact of optimization in newer technologies

  10. comparison of Philips H 3000 and Innova 2000 in PCI characteristics of procedures & lesions (2) % Lecture 8.2: Impact of optimization in newer technologies

  11. comparison of Philips H 3000 and Innova 2000 in PCI performance & complexity indexes H 3000 2 84 59 1,8 Innova 1,6 1,47 48 1,37 1,4 40 1,2 1 1 0,93 0,8 24,1 21,6 0.30 0.29 0.34 0.26 0,6 0,4 r (with fluoro time) 11,6 11,5 0,2 0 GISE Index Comp. Index Lecture 8.2: Impact of optimization in newer technologies (m’)

  12. comparison of Philips H 3000 and Innova 2000 in diagnostic procedurescharacteristics of patients & procedures H 3000: 1401 pts, 92% of tot. studied in the year 2002 Innova: 702 pt, 69% of tot. studied between Jan-Oct 2003 (%) Lecture 8.2: Impact of optimization in newer technologies

  13. comparison of Philips H 3000 and Innova 2000 in diagnostic procedures performance indexes and exposure parameters measured 60 H 3000 calculated 54 54 Innova 50 45.88 40 35.32 31.06 30 28 27.05 24 20.39 1,3 18.83 20 15.8 15.6 10.67 10 4.4 4.2 0 tot. DAP Fluoro T cine DAP room occ. proced. T fluoro DAP contrast (dl) Lecture 8.2: Impact of optimization in newer technologies m’ Gy * cm2

  14. why the anticipated 30% per-frame dose reduction of DFP technology does not translates into an effective dose reduction to patients ? Lecture 8.2: Impact of optimization in newer technologies

  15. H 3000 field of view (cm) 23/18/14 cine mode 12,5/25 fps fluoro mode low/medium/high filter automatic Innova field of view (cm) 20/17/15/12 cine mode 15/30 fps pref 1/pref 2 (lower dose) fluoro mode low/normal filter manual differences in operating conditions of the two systems Lecture 8.2: Impact of optimization in newer technologies

  16. Exact framing (underframing) • maximum intensifier output used • the smallest image • Total overframing • intensifier output underused • the largest image • Maximum square framing • compromise in intensifier output • compromise in image size • Maximum horizontal framing • compromise in intensifier output • compromise in image size Modified from Green, Lippincott - Raven 1996 Lecture 8.2: Impact of optimization in newer technologies

  17. 20 cm 23 cm 400 cm2 375 cm2 Lecture 8.2: Impact of optimization in newer technologies

  18. other possibilities…… • patients may not be the same • procedures may not be the same • operators’ behavior • filters/collimation • use of “difficult” projections (fluoro/cine) • focus-detector mean distances • ……… Lecture 8.2: Impact of optimization in newer technologies

  19. collimators use in INNOVA to reduce exposure FOV 15 dose reduction 25% Lecture 8.2: Impact of optimization in newer technologies

  20. collimators use in INNOVA to reduce exposure FOV 20 Lecture 8.2: Impact of optimization in newer technologies

  21. H 3000 improper filtering causes image deterioration proper filtering Lecture 8.2: Impact of optimization in newer technologies

  22. INNOVA improper filtering does not cause image deterioration Lecture 8.2: Impact of optimization in newer technologies

  23. variation in exposure rate with projection anthropomorphic phantom (average-sized) measurements Cusma JACC 1999 Lecture 8.2: Impact of optimization in newer technologies

  24. Distance between patient and detector Lecture 8.2: Impact of optimization in newer technologies

  25. The inverse square law Source Because the same energy is spread over a surface 4 times larger at a doubled distance, the same object will receive only a fourth of the dose when moved away from “d” to “2d” d 2d Doubling the distance from the source divides the dose by a factor of 4 Lecture 8.2: Impact of optimization in newer technologies

  26. The inverse square law Lecture 8.2: Impact of optimization in newer technologies

  27. Collimation Lecture 8.2: Impact of optimization in newer technologies

  28. Anti-scatter grid Lecture 8.2: Impact of optimization in newer technologies

  29. staff position in the cath. lab. mobile screens ceiling bed technician 2 technician 1 nurse MD Lecture 8.2: Impact of optimization in newer technologies

  30. staff neck dose in the cath. lab.57 procedures MD nurse Technician 1 350 300 250 200 m Gy/procedura 150 100 50 0 procedure Cathet Cardiovasc Diagn 1997 Cardiologia & Fisica Sanitaria - Udine Lecture 8.2: Impact of optimization in newer technologies

  31. Example of the optimization process • Data collection • procedures, DAP, fluoro time • Data analysis • reliability of data • Discussion & processes review • collimators/filters use, FOV, projections • Implementation of changes • more precise data collection, collimators/filters use, FOV 17 whenever possible, avoiding LAO projections • Data verification Lecture 8.2: Impact of optimization in newer technologies

  32. Innova 2000. Changes in exposure parameters over time diagnostic procedures Jul. 2003 - Feb. 2004 Lecture 8.2: Impact of optimization in newer technologies

  33. procedure optimization in the cath. lab.patients and staff share a lot…… • correct indications • fluoro time reduction • frame rate reduction (25 12,5/sec) • collimation/filtering • LAO cranial projection limitation • distance from X rays source • protective screen use • protective glasses and gloves (patient) (staff) Lecture 8.2: Impact of optimization in newer technologies

  34. PCI optimization comparison of two periods Cardiologia & Fisica Sanitaria - Udine -37% p<0.0001 p=ns 1021 ± 600 715 ± 462 640 ± 393 652 ± 458 CI=0.65 CI=0.58 p=ns Lecture 8.2: Impact of optimization in newer technologies

  35. 1994-1998 - 71% procedure optimizationannual hand dose (cardiologist) Cardiologia & Fisica Sanitaria - Udine mSv + 2% - 27% - 49% - 23% Lecture 8.2: Impact of optimization in newer technologies

  36. procedure optimization DAP measurements at Udine Hospital (all procedures) Gy*cm2 Lecture 8.2: Impact of optimization in newer technologies

  37. PCI optimization over time Gy*cm2 Lecture 8.2: Impact of optimization in newer technologies

  38. closing remarks • angiographic procedure optimization is a continuous process of research and audit • this must involve Scientific Societies and single operators • must be based on co-operation of all professionals involved (cardiologists, physicists, radiologists, technicians) Lecture 8.2: Impact of optimization in newer technologies

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