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

Anti-scatter grids are commonly used in x-ray imaging systems to reduce scatter radiation reaching the image receptor. Anti-scatter grid performance and validation can be simulated through use of Monte Carlo (MC) methods. Our recently reported work has modified existing MC codes resulting in improved performance when simulating x-ray imaging. The aim of this work is to validate the transmission of x-ray photons in grids from the recently reported new MC codes against experimental results and results previously reported in other literature. The results of this work show that the scatter-to-primary ratio (SPR), the transmissions of primary (T ), scatter (T), and total (T ) radiation determined using this new MC code system have strong agreement with the experimental results and the results reported in the literature. T, T , T, and SPR determined in this new MC simulation code system are valid. These results also show that the interference effect on Rayleigh scattering should not be neglected in both mammographic and general grids' evaluation. Our new MC simulation code system has been shown to be valid and can be used for analysing and evaluating the designs of grids.

In X‐ray imaging, anti‐scatter grids are used to reduce scatter radiation reaching image receptors, hence improving image quality. Optimization of grid performance is essential for improving image diagnostic quality and minimizing radiation doses to patients. This work investigated the performance of a series of grid designs modeled from the design of typically focused grid with grid ratio 8:1 (r8) and strip height 1.7 mm (h1.7) for high‐energy radiographic applications. Monte Carlo simulation was used to evaluate designs (r8h1.7) which had the strip thickness changed from 6 to 150 μm in 2 μm increments and the interspace distance fixed at 214 μm. The transmissions of radiation in grid materials were modeled by using a regression with radial‐basis‐function‐networks (RBFNS). KSNR was then determined from RBFNS models of radiation transmissions. The optimal strip‐thickness was obtained at the maximum signal‐to‐noise ratio (SNR) improvement factor (KSNR). For high‐energy applications at 100 peak‐kilo‐voltage (kVp) and 30 cm PMMA thickness, the optimal lead‐strip‐thickness was found approximately 74 μm resulting in a strip‐frequency approximately 35 per cm (N35). Using the optimal thickness for imaging condition at 100 kVp and 30 cm thickness, the KSNR would increase by approximately 5.3%. This work showed the existence of optimal strip‐thickness for a series of grids with a given grid‐ratio, strip‐height, strip‐, and interspace materials. The findings are useful and provide guidance to improve grid designs for better performance that will essentially lead to better image quality and better radiation protection for patients.

Antiscatter grids are used in biomedical X-ray imaging to improve image quality by reducing scatter radiation reaching the image receptor. However, this comes at the cost of increasing radiation exposure. Grid performance can be improved by optimizing strip-thickness, which reduces radiation exposure, leading to greater benefits achieved by the grid. Evidence has shown that strip height may also affect grid performance. This work investigates optimization of grid performance by varying both the strip thickness and height for a constant grid-ratio of 15:1 (r15). A series of grid designs using lead strips and carbon-fiber-interspace materials for grids for high-energy use was evaluated. The performance of these designs was determined by adopting a Monte Carlo simulation. For each grid design, the signal-to-noise ratio improvement factor (K SNR ) was determined. A maximum value of K SNR (1.895) was found among these designs at a strip height of 6.8 mm and a thickness of 66.8 μm. The best performance of the r15-series grids is 6% greater than that of a grid design with a grid ratio of 15:1 and a strip frequency of 44 cm −1 (found in the literature); consequently, the transmission of scatter radiation is reduced by 40%. The results show that grid designs can be optimized by both the strip height and thickness. If the optimization of the strip height and thickness cannot be done simultaneously, the recommendation is to optimize the strip height for better radiation protection without compromising the grid performance. The findings provide useful guidance for designing high-performance antiscatter grids to reduce radiation exposure of patients.

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