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 Lecture 9.1: Examples of good and bad practice

Lecture 9.1: Examples of good and bad practice Philips systems Lecture 9.1: Examples of good and bad practice

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

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

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

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

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

Use of wedge filter in right projections

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

Lecture 9.1: Examples of good and bad 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

Philips Integris: Use of wedge filter in left projections

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

Lecture 9.1: Examples of good and bad 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

Use of wedge filter in right and left projections

Lecture 9.1: Examples of good and bad practice

Lecture 9.1: Examples of good and bad 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

Geometry with small field size

Lecture 9.1: Examples of good and bad practice

Lecture 9.1: Examples of good and bad practice 68 cm2 28 cm2 26 cm2 Lecture 9.1: Examples of good and bad 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

Geometry with big field size

Lecture 9.1: Examples of good and bad practice

Lecture 9.1: Examples of good and bad practice 1.2 Gy 113 cm2 0.6 Gy 41 cm2 Lecture 9.1: Examples of good and bad 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

No wedge filter used. Geometry with big radiation field size No wedge filter used. Geometry with big radiation field size. Overlapping of radiation fields could occur.

Lecture 9.1: Examples of good and bad practice

Lecture 9.1: Examples of good and bad practice 319 cm2 234 cm2 91 cm2 Lecture 9.1: Examples of good and bad 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

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

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

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