International Atomic Energy Agency Impact of Optimization in Newer Technologies Impact of Optimization in Newer Technologies L 8.2

International Atomic Energy Agency

Impact of Optimization in Impact of Optimization in Newer TechnologiesNewer Technologies

L 8.2

Lecture 8.2: Impact of optimization in newer technologies 2Radiation Protection in Cardiology

Educational ObjectivesEducational Objectives

1. What benefit of digital flat panel technology be expected on patient dose

2. How to translate this into practice3. Experience with optimisation


Anticipated per-frame dose reduction with Digital Flat Panel technology is 30%


Motorized Iris

Video Camera

Image Intensifier

DE

TE

CT

OR

DE

TE

CT

OR

Photons

Cesium Iodide (CsI)

Light

Amorphous Silicon Panel(Photodiode/Transistor Array)

Digital DataDigital Data

Electrons

Read Out Electronics

Photons

Cesium Iodide (CsI)

Light

Photo-cathode

Video SignalVideo Signal

Electrons

Output screen

Light

CCD or PUT

Electrons

Readout Electronics

1

3,000

400

400,000

2,400

Particles #


diagnostic and interventional activitydiagnostic and interventional activityUdine,Udine, years 1990-2002years 1990-2002

0

500

1000

1500

2000

'90 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03

diagnostic

PCI

Philips OM 200 (1983)

Philips Integris 3000 (1995)

performed by 3 interventionalists except in 1998


Innova 2000 at Udine CenterInnova 2000 at Udine Center

• activity started

• 04/12/2002

• Jan.-Oct. 2003

• 1421 procedures (79% of total)

• 1019 diagnostic

• 402 PCI


• 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

d2

d3

S3

S2

S1

D1

D2

D3

1000

1000

1000

Dose Area Product


comparison of Philips H 3000 and Innova 2000 in PCI comparison of Philips H 3000 and Innova 2000 in PCI characteristics of patientscharacteristics of patients

66

77

1,9

56

31,2 33,4 35,4

66

78

1,9

53

30,8

38,5

30,8

0

10

20

30

40

50

60

70

80

90

age

(y)

male sex

(%)

BSA

(sqm)

EF

(%)

1 2 3

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 (%)


65,9

22,9

11,314,8

6,12,6 3,2

56,5

25,5

15,3

10,2

3,6 2,96,6

0

10

20

30

40

50

60

70

H 3000

Innova

%

comparison of Philips H 3000 and Innova 2000 in PCI characteristics of procedures & lesions (1)


29

22,2

6,2

18,1

4,8

12,8

37,2

22,3

4,7

16,1

3,6 3,3

0

5

10

15

20

25

30

35

40

H 3000

Innova

%

comparison of Philips H 3000 and Innova 2000 in PCI characteristics of procedures & lesions (2)


0

10

20

30

40

50

60

70

(m’)

comparison of Philips H 3000 and Innova 2000 in PCI performance & complexity indexes

1,37

1

1,47

0,93

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

Com

p. In

dex

GIS

E In

dex

r (with fluoro time)

0.30 0.29 0.34 0.26

11,6

11,5

40

48

59

84

24,1 21,

6

H 3000

Innova


comparison of Philips H 3000 and Innova 2000 in diagnostic comparison of Philips H 3000 and Innova 2000 in diagnostic proceduresprocedurescharacteristics of patients & procedurescharacteristics of patients & procedures

67

1,9

72

99

71

20 1812 9

67

1,9

74

98

69

2024

19

9

0

20

40

60

80

100

120 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 13Radiation Protection in Cardiologym’ Gy * cm2

measured

comparison of Philips H 3000 and Innova 2000 in diagnostic procedures performance indexes and exposure parameters

calculated

4.2

24

54

15.6

20.39

10.67

31.06

4.4

28

54

15.8

27.05

18.83

45.88

35.32

0

10

20

30

40

50

60

Fluoro T

proced. T

room occ.

contrast

(dl)

cine DAP

fluoro DAP

tot. DAP

1,3

H 3000

Innova


why why the anticipated 30% per-frame dose the anticipated 30% per-frame dose reduction of DFP technology does not reduction of DFP technology does not

translates into an effective dose reduction translates into an effective dose reduction to patientsto patients


differences in operating conditions of the two systemsdifferences in operating conditions of the two systems

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 fpspref 1/pref 2 (lower dose)

• fluoro mode

low/normal

• filter

manual


Exact framing (underframing) maximum intensifier output used the smallest image

Total overframing intensifier output underused the largest image

Maximum horizontal framing compromise in intensifier output compromise in image size

Maximum square framing compromise in intensifier output compromise in image size

Modified from Green, Lippincott - Raven 1996


20 cm23

cm

400 cm2

375 cm2


other possibilities……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

………


collimators use in INNOVA to reduce exposure

FOV 15

dose reduction 25%


FOV 20

collimators use in INNOVA to reduce exposure


proper filtering

improper filtering causes image deterioration

H 3000


INNOVAimproper filtering does not cause image deterioration


variation in exposure rate with projectionanthropomorphic phantom (average-sized) measurements

Cusma JACC 1999


Distance between patient and detector


d

2d

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”

Source

Doubling the distance from the source divides the dose by a factor of 4

The inverse square law


The inverse square law


Collimation


Anti-scatter grid


MD

nurse

technician 1

staff position in the cath. lab.

mobile screens

ceiling bed

technician 2


staff neck dose in the cath. lab.staff neck dose in the cath. lab.57 procedures57 procedures

0

50

100

150

200

250

300

350

procedure

G

y/p

roce

du

ra

MD

nurse

Technician 1

Cathet Cardiovasc Diagn 1997Cardiologia & Fisica Sanitaria - Udine

MD

nurse

technician 1

staff position in the cath. lab.

mobile screens

ceiling bed

technician 2


Example of the optimization processExample 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


Innova 2000. Changes in exposure parameters over time Innova 2000. Changes in exposure parameters over time diagnostic procedures Jul. diagnostic procedures Jul. 2003 - Feb. 20042003 - Feb. 2004

0

1

2

3

4

5

J ul-

Aug

Sept-

Oct

Nov-

Dec

J an-

Feb

Fluoro T (m')

25

26

27

28

29

30

31

32

33

34

J ul-

Aug

Sept-

Oct

Nov-

Dec

J an-

Feb

Tot DAP(Gy*cm2)


procedure optimization in the cath. lab.procedure optimization in the cath. lab.patients and staff share a lot……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

(staff)

(patient)


PCI optimization PCI optimization comparison of two periodscomparison of two periods

0

200

400

600

800

1000

1200

giu 96-nov 96 n 100 ott 97-mag 98 n 100

fluoro t = sec

DAP=cGy*cm2715

± 462652

± 458

1021± 600

640± 393

-37% p<0.0001

p=ns

CI=0.65 CI=0.58p=ns

Cardiologia & Fisica Sanitaria - Udine


procedure optimizationprocedure optimizationannual hand dose (cardiologist)annual hand dose (cardiologist)

0

10

20

30

40

50

60

1994 1995 1996 1997 1998

n. procedurex10

dose mSv- 27%

+ 2%

- 49% - 23%

Cardiologia & Fisica Sanitaria - Udinem

Sv

1994-1998 - 71%


0

10

20

30

40

50

60

70

1998 1999 2000 2001 2002

DAP cine

DAP fluoro

DAP totGy*c

m2

procedure optimization procedure optimization DAP measurements at Udine Hospital (aDAP measurements at Udine Hospital (all proceduresll procedures))


Gy*c

m2

0

5

10

15

20

25

30

35

40

45

1998 1999 2000 2001 2002

0

1

2

DAP cine

DAP fl uoro

DAP tot

complexity score

PCI optimization over time


closing remarksclosing 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)

Documents

International Atomic Energy Agency Impact of Optimization in Newer Technologies Impact of Optimization in Newer Technologies L 8.2