A Comparative Analysis of the Dosimetric, Alignment, and Setup Efficiency in Left Breast Cancer Radiotherapy Treated with Dibh Using ABC and Sgrt 📝

Author: Aaron Conard, Victoria Croog, Marie Gurka, Lan Lin 👨‍🔬

Affiliation: Johns Hopkins University 🌍

Abstract:

Purpose:
This study evaluates the utility of the Active Breathing Coordinator (ABC) and Surface Guided Radiation Therapy (SGRT) techniques in implementing Deep Inspiration Breath Hold (DIBH) for left breast cancer treatment, with a focus on intra-fractional dose consistency, patient positioning accuracy, and set-up efficiency.
Methods: Data was acquired and analyzed from 20 patients that underwent DIBH with ABC (n=10) and SGRT using AlignRT (n=10). Each patient’s weekly CBCT was fused and utilized to calculate the mean heart dose (MHD) and mean lung dose for the left lung (MLD) for each fraction. The acquired mean dose data was used to assess the difference and standard deviation between the treatment and planned doses. CBCT shifts were studied laterally, longitudinally and vertically to measure 3D positional reproducibility and the patient set-up times were tracked per fraction in order to examine set-up efficiency.
Results:
Initial findings indicate that both techniques exhibit comparable intra-fractional variability in MHD and MLD. The MLD for the ABC and SGRT 3.84cGy and 1.28cGy respectively, while the standard deviations were 3.23 (ABC) and 5.09 (SGRT). The t-test indicates that there is no statistically significant difference (p=0.14). The mean absolute dose difference from the planned dose for the MHD is 3.95% (ABC) and 3.26% (SGRT). There was no statistically significant difference found between the groups (p=0.78). The average mean shifts for the ABC and SGRT groups were 0.646 cm and 0.537 cm, respectively. There was no significant difference found (p=0.2). The average set-up time for SGRT was slightly more efficient, with an average of 3.5 minutes, compared to 4.1 minutes for ABC.
Conclusion:
While there were no significant statistical differences found within the collected data, the SGRT method seems to offer a unique degree of comfort to the patient’s experience that differs from ABC, while providing a more efficient setup time.