ESTRO 2024 - Abstract Book

S5921

RTT - Service evaluation, quality assurance and risk management

ESTRO 2024

Figure 1. This figure displays the three cube types: Peek, Titanium Solid, and Titanium Mesh.

Results:

In the experiment, the doses of Peek at 80 kVCT and 140 kVCT varied depending on density assignment: 179.5 cGy and 201.3 cGy (80 kVCT) and 197.2 cGy and 235.1 cGy (140 kVCT). Titanium solid and Mesh recorded doses of 244.9:245.6 cGy at 80 kVCT and 246.6:223.3 cGy at 140 kVCT without density assignment. When MAR and Extended HU values were applied, both Peek and Titanium exhibited an average dose of 160 cGy, which was below the prescribed dose. HU measurements indicated that Titanium solid at 80 kVCT had HU values of 3078:7970 (x-axis) and 3070:5778 (y-axis), while Titanium Mesh had values of 2267:2243 (x-axis), and Peek had values of 80:78 and 100:93. Regarding Cube length measured from the CT image's Iso-center, Peek's dimensions were 0.87:0.87 cm (x-axis, 80:140 kVCT) and 1.00:0.96 cm (y-axis). Titanium solid measured 0.85:0.87 cm (x-axis) and an average of 1.06:0.98 cm (y-axis), while Titanium Mesh showed dimensions of 0.91:0.85 cm (x-axis) and 0.93:0.93 cm (y-axis). It's important to note that the tube voltage difference had minimal impact on Cube length accuracy when considering MAR and Extended HU values.

Conclusion:

In conclusion, the use of medical implants, particularly 3D-printed craniofacial implants, in medical procedures presents a significant challenge in radiotherapy planning for craniofacial tumors. The discrepancies in CT Hounsfield Unit (HU) values caused by metal materials and the associated artifacts can impact the accuracy of dose calculations and the delineation of critical structures. This study has shown that 80 and 140 X-ray tube voltages, with or without Metal Artifact Reduction (MAR) and Extended HU values, can influence the dose measurements, but the differences are not substantial. Both Peek and Titanium implants displayed lower doses than the prescribed ones when MAR and Extended HU values were applied. It is essential for medical professionals to be aware of these factors when planning radiotherapy for patients with such implants, as this can affect the treatment outcome and safety.