EuroSafe Imaging 2020
Experimental, Prospective, Dosimetric comparison, Radiation safety, Dosimetry, Fluoroscopy, Radioprotection / Radiation dose, Radiation physics, Action 4 - Dose management systems, Multicentre study
J. M. P. Venâncio, L. Peralta
Description of activity and work performed
The developed dosimeter consists of a BC-404 scintillator (from Saint-Gobain), 10 mm long and 2 mm in diameter, connected to a SK-80 optical clear fiber. The signal produced in the scintillator is read by a R647P photomultiplier (PMT) from Hamamatsu. The output of the PMT is feed to an integrated amplifier MTI04CS produced by MaZeT. The output signal from the amplifier is digitized by an Arduino UNO microcontroller. The acquisition system is based on a Raspberry Pi microprocessor. During the testing phase a simple graphical user interface was made to verify the validity and quantity of the data acquire by the prototype system.
The prototype was tested in laboratory environment using a 50 kV X-ray tube and in clinical environment using a 125 kV X-ray beams produced by a floor angiography Artis Zee from Siemens Healthineers.
In both scenarios the tested dose rate range was between 0.003 and 0.05 mGy/s measured with the scintillation dosimeter and a Farmer ionization chamber placed inside a PMMA phantom (figure 1).
The images acquired proved the almost total transparency of the scintillator dosimeter (figure 2). In this figure it can be seen the image of the ionizing chamber, in the left side of the figure, and the image of the system detectors, in the right side of the figure. By contrast the fiber is almost invisible.
The data acquire in the clinical environment is presented in figure 3. A linear relation is obtained between the dose measure by the ionization chamber and the signal of the prototype. The response is almost identical in fluoroscopic and kinematic modes.