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Examples of Good & Bad Practice: Effect of the wedge filter and field size in the skin dose distribution. L 9.1. Educational Objectives. How wedge filter & field size affect the skin dose When and how to use wedge filter. Philips systems. Series 14: KVP: 88
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Examples of Good & Bad Practice:Effect of the wedge filterand field size in the skin dose distribution L 9.1
Educational Objectives • How wedge filter & field size affect the skin dose • When and how to use wedge filter Lecture 9.1: Examples of good and bad practice
Philips systems Lecture 9.1: Examples of good and bad practice
Series 14: KVP: 88 Distance source to detector: 1048 Exposure time 8 X-ray tube current 467 Intensifier size 169.9 mm Positioner primary angle 5.2 (LAO) Positioner secondary angle 28.3 13 Sep 04; 40414 Example of lack of wedge filter use in a left projection. Image quality is not good (too bright in the upper left corner of the image) and in addition, more dose per frame than necessary. Bad practice!. Lecture 9.1: Examples of good and bad practice
Series 21: KVP 87 Distance source to detector 995 Exposure time 8 X-ray tube current 472 Positioner primary angle - 41.1 (RAO) Positioner secondary angle 28.8 13 Sep 04; 40414 Example of lack of wedge filter use in a right projection. Image quality is not good (too bright in the upper right corner of the image) and in addition, more dose per frame than necessary. . Bad practice!. Lecture 9.1: Examples of good and bad practice
Series : 6 (0008,0020) : Study Date : 21/09/2004 (0008,0080) : Institution Name : HOSPITAL SEVERO OCHOA (0008,1090) : Manufacturer's Model Name : INTEGRIS Allura Flat Detector (0018,0060) : KVP : 78.0 (0018,1110) : Distance Source to Detector : 1.08 (0018,1111) : Distance Source to Patient : 0.765 (?) (0018,1150) : Exposure Time : 6 (0018,1151) : X-ray Tube Current : 812 (0018,1510) : Positioner Primary Angle : -31.2 (0018,1511) : Positioner Secondary Angle : 32.2 Example of appropriate use of the wedge filter. (flat panel). Good practice!. Lecture 9.1: Examples of good and bad practice
No wedge filter used. Image partially saturated. Bad practice!. Lecture 9.1: Examples of good and bad practice
0.5 mGy/fr 0.8 mGy/fr (60% more) Lecture 9.1: Examples of good and bad practice
Effect of the wedge filter in skin dose distribution (right projections). Saving skin dose and improving image quality.Good practice!. Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
Effect of the wedge filter in skin dose distribution (left projections). Saving skin dose and improving image quality. Good practice!. Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
68 cm2 28 cm2 26 cm2 Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
1.2 Gy 0.6 Gy 113 cm2 41 cm2 Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
No wedge filter used. Geometry with big radiation field size. Overlapping of radiation fields could occur.
319 cm2 234 cm2 91 cm2 Lecture 9.1: Examples of good and bad practice
Areas in red are saturated in the slow film. Skin dose more than 1.2 Gy. Lecture 9.1: Examples of good and bad practice
Patients who had multiple coronary angiographies and who underwent more than four PTCAs. 7824 PTCAs performed during 14 years was analysed. • 14 patients were included in the study. Each patient had undergone between 4 and 14 coronary angiographies and between 5 and 10 PTCAs, performed over a period of 2-10 years. Lecture 9.1: Examples of good and bad practice
Mean values of maximum skin dose per procedure were 217 mGy for the diagnostic studies and 391 mGy for the PTCAs. • Only a slight radiation skin injury was clinically demonstrated in one patient with a history of 10 coronary angiographies and 10 PTCAs (estimated maximum skin dose 9.5 Gy). Lecture 9.1: Examples of good and bad practice
CONCLUSION: • IC procedures performed on modern X-ray systems under QA programmes and by cardiologists trained in RP, repetition of procedures is not the main cause of possible skin radiation injuries. Lecture 9.1: Examples of good and bad practice