Example of Practice of Radiation Protection
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Transcript of Example of Practice of Radiation Protection
International Atomic Energy Agency
Example of Practice of Radiation Example of Practice of Radiation Protection Protection
L 9.2
Lecture 9.2: Example of practice of radiation protection 2Radiation Protection in Cardiology
Educational ObjectivesEducational Objectives
1. How awareness of radiation protection and close cooperation with medical physics / radiation safety staff helps
2. Avoidance of skin injuries
Lecture 9.2: Example of practice of radiation protection 3Radiation Protection in Cardiology
IntroductionIntroduction• The evaluation of maximum local skin dose from an
interventional procedure is difficult: • On-line evaluation: dosemeter or computer code
• Off-line methods more accurate: use of large area detectors, time consuming (adopted for a limited number of patients)
• It should be important to periodically evaluate incidence of skin injuries in cardiac centres
• A follow-up protocol has been developed in Dimond European research project (www.dimond3.org):• Purpose to identify patients with an high probability of an
high localised skin dose to be submitted to a follow-up.
• The protocol adopts a trigger value in terms of dose-area product (DAP) as a dose quantity indicator of possible localised high skin dose.
Lecture 9.2: Example of practice of radiation protection 4Radiation Protection in Cardiology
Retrospective evaluation of skin injuries on Retrospective evaluation of skin injuries on patients of Udine cardiac centrepatients of Udine cardiac centre
• Patient can be submitted to repeated cardiac procedures in short period of time
• Methodology: • Analyse database of patients submitted to diagnostic and
therapeutic procedures in a 4 years period
• Detect patients with highest cumulative DAPs (due to repeated procedures) selecting an appropriate DAP trigger value
• Evaluate maximum local skin dose
• Submit selected patients to a clinical evaluation to detect possible skin injuries
Lecture 9.2: Example of practice of radiation protection 5Radiation Protection in Cardiology
Patient database: CA and PTCA in Udine hospital from 1998 to 2002
SAMPLE COLLECTION 21 April 1998 - 17 April 2002
NUMBER OF PROCEDURES 5517
N. OF PTCA PROCEDURES 1843
N. OF CA PROCEDURES 3674
N. OF PATIENTS 3332
Lecture 9.2: Example of practice of radiation protection 6Radiation Protection in Cardiology
CA and diagnostic procedures
No. of procedures 3674
Mean DAP37.5
Gycm2
Median DAP31.2
Gycm2
No. of procedures with
DAP>300Gycm2
1
DAP distribution of CA procedures
0
100
200
300
400
500
0 50 100 150 200 250 300
Gy cm^2
Fre
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Lecture 9.2: Example of practice of radiation protection 7Radiation Protection in Cardiology
PTCA procedures
No. of procedures
1843
Mean DAP66.1
Gycm2
Median DAP48.3
Gycm2
No. procedures with
DAP>300Gycm2
13 (0.7%)
DAP distribution of PTCA procedures
020406080
100120140160
0 50 100 150 200 250 300 350 400 450 500
Gy cm^2
Freq
uenc
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Lecture 9.2: Example of practice of radiation protection 8Radiation Protection in Cardiology
No. of procedures per patient
1 2 3 4 5 6 7 >7
No. of patients 1967 940 194 138 41 29 14 9
No. of patients 3332
Mean DAP78.6
Gycm2
Median DAP50.6
Gycm2
No. of patients with DAP>300Gycm2 87 (2.6%) 0
100
200
300
400
500
600
0 100 200 300 400 500 600 700
Gy cm^2
Fre
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Frequencies of repeated procedures and cumulative dose
Lecture 9.2: Example of practice of radiation protection 9Radiation Protection in Cardiology
Sample of patients Sample of patients extracted for the follow-up studyextracted for the follow-up study
79 patients with a cumulative DAP>300 Gycm2 extracted from the databaseDistribution of number of procedures performed and cumulative DAP
0
5
10
15
20
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DAPtotal (Gycm2)
No.
of p
atie
nts
024
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1012141618
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Number of procedures/patient
No.
of p
atie
nts
Lecture 9.2: Example of practice of radiation protection 10Radiation Protection in Cardiology
Sample of patients Sample of patients extracted for the follow-up studyextracted for the follow-up study
Maximum local skin dose evaluated for the 79 patients
02468
1012141618
1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7Maximum Local Skin Dose (Gy)
No
. of
pat
ien
ts
Lecture 9.2: Example of practice of radiation protection 11Radiation Protection in Cardiology
Maximum local skin dose (MSD) Maximum local skin dose (MSD) assessmentassessment
• Correlation between DAP and MSD has been evaluated: operator and installation dependent
• Skin dose distributions measured on a sample of patients with radiochromic films
MSD= 0.0141*DAP Maximum local skin dose versus DAPfor PTCA
PSD= 0.0141*DAP
0.0
1.0
2.0
3.0
4.0
0 50 100 150 200 250DAP (Gycm2)
PSD
(Gy)
Lecture 9.2: Example of practice of radiation protection 12Radiation Protection in Cardiology
Skin dose assessment (patient no. 1)Skin dose assessment (patient no. 1)
• Patient no. 1: Total maximum local skin dose 6,7 Gy Procedure type DAP per
procedure(Gycm2)Maximum local skin dose
(Gy)
Diagnostic 86.9 0,416
Diagnostic 86.3 0,413
Diagnostic 26.8 0,128
Ad hoc PTCA 57.1 0,509
Diagnostic 108.6 0,520
Diagnostic 73.8 0,354
Ad hoc PTCA 135.6 1,208
Diagnostic 28.4 0,136
Ad hoc PTCA 33.8 0,301
Election PTCA 84.7 0,755
Diagnostic 58.4 0,280
Ad hoc PTCA 115.3 1,027
Diagnostic 27.2 0,130
Diagnostic 33.5
Ad hoc PTCA 39.2
Lecture 9.2: Example of practice of radiation protection 13Radiation Protection in Cardiology
ConclusionsConclusions
• 56 patients received medical examination with particular focus on the more exposed skin area.
• None of visited patients presented skin lesions that could be attributed to high dose X-ray irradiation
• The result assures cardiologists and medical physicists that, if proper quality assurance and radiation protection programme is established, the frequency of skin injuries can be very low also when repeated procedures are taken into account