ESTRO 2024 - Abstract Book

S3840

Physics - Image acquisition and processing

ESTRO 2024

Figure 2. Workflow of the FACT method. Starting with two photos from the electron applicator, images undergo processes including 1) ROI cropping, 2) grayscale conversion and Gaussian filtering, 3) center identification, 4) distance measurement from center to contour at 5-degree intervals (adjustable), 5) comparison of two images to determine magnification factors, and 6) final shape output for electron cutout fabrication. This led to the creation of an optimized contour, primed for cutout applications. For evaluation, a comparative study was made, where FACT was juxtaposed against two widely recognized contouring methods: the traditional hand drawn technique and the CT scanning-based approach. The comparison leveraged a simple quantity, area matching ratio (AMR), offering insights into the accuracy and reliability of our proposed method.

Results:

Evaluations were conducted on various shapes using three contour delineation techniques: Hand-drawn, CT scanning-based, and FACT. For a representative set of results: the original shapes had areas of 19.80 cm 2 (pear-shape), 24.10 cm 2 (strawberry-shape), 28.27 cm 2 (orange-shape), and 24.19 cm 2 (lemon-shape). The hand-drawn method yielded deviations with a mean AMR of 1.019±0.099. The CT scanning-based method demonstrated a closer alignment with a mean AMR of 0.957±0.022. Notably, the FACT method, utilizing advanced imaging capabilities, produced results with a mean AMR of 0.998±0.005, highlighting its both accuracy and precision. Table 1 provides a comprehensive view of the results for all tested shapes, detailing their original areas alongside the estimated areas and AMR values obtained using the three contour delineation techniques. Table 1. Comparison of the area measurements (in cm 2 ) and area matching ratio (AMR) for various test shapes obtained from different methods: Hand-drawn, CT scanning-based, and FACT. The mean and standard deviation (Mean±SD) for each method are presented at the bottom.