Added copper filtration in digital paediatric double-contrast colon examinations: effects on radiation dose and image quality.
Paediatric double-contrast barium enema examinations are usually performed at high tube voltage, 102-105 kV. The aim of this study was to investigate how much the effective dose to the child could be reduced by increasing the X-ray energy further by adding copper filter in the beam, and if this dose reduction could be achieved without endangering image quality. Organ doses to an anthropomorphic phantom simulating a 1-year-old child was measured using thermoluminescence dosimetry for assessment of the effective dose and this value was compared with the energy imparted which was obtained from kerma-area product measurements. To verify that the image quality achieved with this added filtration was still diagnostically acceptable, the study included 15 patient examinations. Since the increased X-ray energy will most probably affect low-contrast objects, image quality was also evaluated with two different phantoms containing low-contrast objects. Effective dose for a complete examination can be decreased 44 % and energy imparted 77 % when a 0.3-mm copper filter is inserted in the beam at tube voltage 102 kV. The patient study did not show any significant deterioration of image quality, whereas phantom measurements of contrast-detail resolution and signal-to-noise ratio was marginally impaired by the added copper filtration. This technique is now in clinical practice for paediatric colon examinations.
Hansson
B
B
Department of Hospital Physics, Karolinska Hospital, S-171 76 Stockholm, Sweden.
Finnbogason
T
T
Schuwert
P
P
Persliden
J
J
D001466:Barium Sulfate; D003106:Colon / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003300:Copper; D004733:Enema; D005260:Female; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D007223:Infant; D008297:Male; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D013679:Technology, Radiologic; D013819:Thermoluminescent Dosimetry
D003287:Contrast Media; D001466:Barium Sulfate; D003300:Copper