A new solution for radiation transmission in anti-scatter grids

Abstract

Analytic calculations of radiation transmission in focused grids or parallel grids are currently performed using the Day and Dance method. In parallel grids, this method calculates the mean transmission of radiation of grid units each of which consists of a strip and the adjacent interspace. The Day and Dance method extrapolates grid-unit-mean transmission of uniformly distributed radiation in focused grids and may underestimate the transmission of scatter radiation. This method fails to preserve detailed grid strips and interspaces information resulting from stationary grids. In this work a new method has been developed to calculate transmission of radiation. This new method and that of Day and Dance were evaluated and compared using Monte Carlo simulation. In the moving grids, the new method calculated the transmission of radiation and accounted for the effect of grid cut-off, which is approximately 4% in the transmission of primary radiation for the mammographic grid (grid ratio 5:1) or 7% for the general grid (grid ratio 15:1). In stationary grids, the new method preserves grid strips and interspace information-observed as grid lines in the x-ray image. The new method improves modelling of radiation transport in focused or parallel grids-whether moving or in stationary-over other analytical methods currently in use. RECEIVED

The determination of the optimal strip‐thickness of anti‐scatter grids for a given grid ratio and strip height

“…Results from previous simulation investigations 13,17 showed that radiation transmissions in grids were affected by the virtual image receptors stimulated with a physical image receptor without all the construction details. In both the grid evaluation and the determination of SPR, this work necessitated the use of a simulated perfectly efficient detector of energy‐integration to avoid any potential bias from the construction of a physical image receptor.…”

“…In this work, the simulation included the interference effect on Rayleigh scattering which has an effect on scatter‐to‐primary ratio (SPR) 13,29,32–35 and Ts 13,35,36 . The simulation of radiation transport in the grid materials were performed using the method of Zhou et al 17 in which the interaction probability of each photon in the grid materials was determined by the path lengths in each type of grid materials. These path lengths were presumably determined as if the photon would traverse the grid materials without an interaction with them.…”

“…There is no information found about grid design to optimize grid performance. It is accepted that forward scatter radiation in the narrow‐beam method 12 influences Tp and forward scatter radiation which should arise in the materials underneath the blocker affects Ts 13,17 . Tp, Ts, and Tt are used to calculate the combined effects of the differential attenuation of the primary radiation and scatter reduction (noise reduction) on image diagnostic quality.…”

Mamografia Digital: estudos dosimétricos e de qualidade da imagem por simulação Monte Carlo

“…As modificações no código que envolviam a dosimetria da mama foram validadas ao comparar os resultados do Report TG-195 22 , Nosratieh et al 31 , Sarno et al 9 e Wu et al 5 . O algoritmo da grade antiespalhamento foi validado previamente 32 comparando os resultados de Zhou et al 33 e Cunha et al 7 3. Resultados e Discussão 3.1.…”

Evaluation of scatter suppression algorithm for X-ray exposure of soft tissue equivalent phantoms over nominal energy range using FLUKA code

“…Several degrading mechanisms exist, including patient voluntary and involuntary motion, detector blur, inferior detective quantum efficiency (DQE) and scatter radiations amongst others. Scatter radiation being the dominant image degradation mechanism, many researchers have investigated hardware based scatter correction methods that currently refer to the use of antiscatter grids (Fetterly and Schueler 2008, Carton et al 2009, Zhou et al 2016, Omondi et al 2020. However, the scatter correction efficacy of anti-scatter grids needs further improvements by improving the grid designs based on the fundamental grids features that include, grid ratio (r), grid frequency (N) and septa to interspace ratio (R) amongst others (Zhou et al 2020).…”