Investigation of scatter fractions for estimating leakage dose in medical X-ray imaging facilities

Abstract

It is essential to make accurate estimates of the scatter of radiation from the human body when calculating the leakage dose in medical X-ray imaging facilities. The scatter fraction varies with the size and shape of the radiation field in a way that is not exactly proportional to the area of the field. Japanese law quotes values for the scatter fraction that are provided by the National Council on Radiation Protection and Measurements, but these data were obtained 30 years ago, using equipment that differed considerably from that employed nowadays. To date, no attempt has been made to confirm whether these data accurately describe current Japanese equipment. In the present study, we used an ion chamber dosimeter to measure scattered radiation fractions, and new scatter factor data are presented that resolve these problems.

Monte Carlo method used to determine scatter fractions for estimating secondary gamma-ray and X-ray photon dose equivalent rates

“…Noto et al (2009), also observed this overestimate compared with their own measurements (the NCRP (2005), values are higher by a factor of 1.3 to 3 for an X-ray tube at 70 kV). It should be pointed out that the values of the NCRP (2005), result from an interpolation of various values from the literature for kinetic energies between 30 and 150 keV.…”

Spectroscopy and dosimetry of secondary radiation for radiology systems

“…Ο γενικός σκοπός της διατριβής αυτής, ήταν η χαρτογράφηση της δευτερογενούς ακτινοβολίας εντός ακτινολογικού θαλάμου σε συμβατικές ακτινολογικές μονάδες και η διέλευση αυτής από κοινά οικοδομικά υλικά για την αξιολόγηση αυτών ως προς την ακτινοπροστασία σε οδοντιατρικές και κτηνιατρικές εφαρμογές, με τη χρήση του απαιτούμενου μετρητικού εξοπλισμού [Edward et al 1965, Petrantonaki et al 1999, Noto et al 2003, Mc Vey et al 2004, Noto et al 2009. Η μέθοδος αναπτύχθηκε χρησιμοποιώντας συμβατική ακτινολογική μονάδα και το μετρητικό εξοπλισμό του Γενικού Νοσοκομείου Αττικής (Γ.Ν.Α) Σισμανόγλειο και του τμήματος Μηχανικών Βιοϊατρικής Τεχνολογίας ΤΕ του ΤΕΙ Αθηνών.…”

“…In addition the inclusion of X-ray filtration, as an exposure parameter for 100 kVp tube voltage, can make the presented results applicable to clinical exposure conditions, like coronary angiography, whereby, added filtration and increased tube voltage is utilized for heavy patients. Furthermore, we also conduct a Monte Carlo Simulation analysis, where we simulate the production of the dose rate of secondary radiation [Noto et al 2003, Noto et al 2009.…”

“…The scatter fraction varies with the size and shape of the radiation field in a way that is not exactly proportional to the area of the field [Noto et al 2003, Noto et al 2009. An important part of determining the radiation protection requirements during X-ray room design is the calculation of the amount of scatter inside and outside the planned locations of the shielding barriers.…”

“…Dose from diagnostic X-ray equipment is delivered from the primary X-rays, the scattered X-rays, and the leakage of the X-ray tube. To calculate the effective dose it is necessary to determine all three [Noto et al 2003, Noto et al 2009. An important part of determining the radiation protection requirements during X-ray room design is the calculation of the amount of scatter inside and outside the planned locations of the shielding barriers [Mc Vey et al 2004, Petrantonaki et al 1999.…”