3181 - Economic Efficiency in Radiotherapy: An Innovative Approach to Customized Bolus

Purpose/Objective(s): Using materials with water-like properties in radiotherapy is crucial for ensuring proper radiation dose distribution in treatments requiring a bolus. While materials like gelatin and agar show potential, the existing scientific literature does not provide enough evidence regarding their specific application as a bolus in radiotherapy. This underscores the urgent need for further validation and research in this area.

Materials/Methods: Four test samples were prepared using different materials to evaluate various densities and properties. The same recipe was used for all samples (see Table 1). The difference between each sample was the percentage of glycerol used: A) 0%: 0 ml, B) 5%: 12.5 ml, C) 10%: 25 ml, D) 15%: 37.5 ml. Control CT scans were performed weekly to evaluate the Hounsfield units (HU), assess the density of each sample, and determine the degree of dehydration.

Results: The HU of four samples (A, B, C, and D) were evaluated in four CT scans (CT 1-4). A progressive increase in HU values was observed in all samples over time. Sample D consistently showed the highest HU values, followed by C, B, and A. From CT 1 to CT 4, all samples exhibited increased HU values, suggesting changes in material density. Sample C showed the most significant increase in HU (from 112.79 to 117.10), which could indicate greater sensitivity to external factors (see Table 2). In this preliminary study, samples with a higher glycerin percentage exhibited more reproducible properties over time, unlike mixtures with lower glycerin concentrations, which showed more significant dehydration and fungal growth after 45 days.

Conclusion: For future work, the number of antifungal agents and glycerin concentration will be increased to improve the consistency of HU over time, maintain the volume of each piece, and enhance their response to high-energy beams for use as treatment bolus.

Abstract 3181 - Table 1: Procedure and list of materials used

Abstract 3181 - Table 2: Hounsfield units (median)