Scanning more bones boosts accuracy of cancer treatment dosing
Researchers found that including six vertebrae instead of one in radiation dose calculations improves precision by more than fivefold, cutting measurement error from 34% to 6%. The finding could help hospitals better predict side effects and optimize personalized dosing for patients receiving Lu-177 radioactive therapy for neuroendocrine tumors and other cancers.
Originaltitel: Multiple vertebrae improves precision in image-based bone marrow absorbed dose estimation in [177Lu]Lu–DOTATATE treatment
BACKGROUND: Lu]Lu-DOTATATE. Bone marrow absorbed dose estimates and their precision were analyzed based on the number of vertebrae included in the calculation. Additional evaluations were performed using both measured (Lung-Spine phantom with spherical inserts) and simulated (digital XCAT phantom) SPECT data, with noise levels matching patients' bone marrow. RESULTS: Increasing the number of vertebrae from one to six improved precision in absorbed doses, reducing the coefficient of variation (COV) from 34 to 6.2%. Only minor differences (0.1%) in bone marrow absorbed dose were observed when adjusting reconstruction parameters from 1 subset, 60 iterations, to 12 subsets, 5 iterations. In the Lung-Spine phantom, smaller volumes (4 mL) were more sensitive to noise than larger volumes (16 mL), with COVs of 36% and 17%, respectively, at 60 updates. In the XCAT phantom, a decrease in recovery was observed in vertebrae near high-uptake regions (L5: 0.63, L1: 0.29), at 60 updates at the highest noise level. CONCLUSION: Including multiple lesion-free vertebrae enhances precision in image-based bone marrow absorbed dose calculations. Nevertheless, careful selection of vertebrae is important, as closely located high-uptake areas can bias absorbed dose estimates. Applying partial volume correction could mitigate spill-out effects, further improving accuracy. Additionally, the minimal differences between reconstruction parameters suggest that bone marrow absorbed dose estimates remain stable across subset configurations.