Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres

M. Martin (1, 2) , A. Hocquelet (3) , F. Debordeaux (1, 2) , L. Bordenave (1, 4, 2) , J.-F. Blanc (5) , P. Papadopoulos (1, 2) , B. Lapuyade (1, 2) , H. Trillaud (1, 6, 2) , J.-B. Pinaquy (1, 2)

1 CIC Bordeaux
2 CHU Bordeaux
3 CHUV - Centre Hospitalier Universitaire Vaudois = Lausanne University Hospital [Lausanne]
4 BIOTIS - Bioingénierie tissulaire
5 Hôpital Haut-Lévêque [CHU Bordeaux]
6 IMB - Institut de Mathématiques de Bordeaux

Purpose: To compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus 99mTc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using 90Y-glass microspheres.Materials and methods: Fifteen patients (8 men, 7 women) with a mean age of 68.3±10.5 (SD) years (range: 47-82 years) who underwent a total of 17 SIRT procedures using 90Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from 99mTc-MAA SPECT/CT using either CBCT or 99mTc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using 90Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (DT), non-tumoral liver, perfused liver (DPL) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρc values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland-Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing-Bablok regression.Results: The intra- and interobserver reliabilities were good-to-excellent (ρc: 0.80-0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8Gy (IQR: -12.7; 16.1) and 5.6Gy (IQR: -13.6; 10.2) for DPL-CBCT and DPL-99mTc-MAA SPECT/CT, respectively. The median differences were 1.6Gy (IQR: -29; 7.53) and 9.8Gy (IQR: -28.4; 19.9) for DT-CBCT and DT-99mTc-MAA SPECT/CT respectively. Passing-Bablok regression analysis showed that both CBCT and 99mTc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate DT and DPL at higher post-treatment doses.Conclusion: CBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of 99mTc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers.

Mots clés: Brachytherapy; Carcinoma; hepatocellular; Cone-beam CT; Radiation dosimetry; SPECT CT; Yttrium-90

Domaines: Sciences du Vivant [q-bio]

M. Martin, A. Hocquelet, F. Debordeaux, L. Bordenave, J.-F. Blanc, et al.. Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres. Diagnostic and Interventional Imaging, 2021, 102, pp.45 - 52. ⟨10.1016/j.diii.2020.09.003⟩. ⟨hal-03493594⟩