Simultaneous 166Ho/99mTc dual-isotope SPECT with Monte Carlo-based downscatter correction for automatic liver dosimetry in radioembolization

Rooij, Rob van; Braat, Arthur J. A. T.; Jong, Hugo W. A. M. de; Lam, Marnix G. E. H.

doi:10.1186/s40658-020-0280-9

Cited by 15 publications

(12 citation statements)

References 20 publications

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“…To minimize patient motion, 99m Tcstannous phytate was administered while the patient remained on the SPECT/CT table in supine position. The optimal 166 Ho-99m Tc ratio, yielding a high accuracy in DI reconstruction, was previously empirically determined by van Rooij et al [9] in our institution, based on phantom data, and the resulting 5:1 166 Ho-99m Tc activity ratio was adopted for this study.…”

Section: Study Populationmentioning

confidence: 99%

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Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

et al. 2020

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Purpose: Accurate dosimetry is essential in radioembolization. To this purpose, an automatic protocol for healthy liver dosimetry based on dual isotope (DI) SPECT imaging, combining holmium-166 (166 Ho)-microspheres, and technetium-99 m (99m Tc)-colloid was developed: 166 Ho-microspheres used as scout and therapeutic particles, and 99m Tc-colloid to identify the healthy liver. DI SPECT allows for an automatic and accurate estimation of absorbed doses, introducing true personalized dosimetry. However, photon crosstalk between isotopes can compromise image quality. This study investigates the effect of 99m Tc downscatter on 166 Ho dosimetry, by comparing 166 Ho-SPECT reconstructions of patient scans acquired before (166 Hoonly) and after additional administration of 99m Tc-colloid (166 Ho-DI). Methods: The 166 Ho-only and 166 Ho-DI scans were performed in short succession by injecting 99m Tc-colloid on the scanner table. To compensate for 99m Tc downscatter, its influence was accounted for in the DI image reconstruction using energy window-based scatter correction methods. The qualitative assessment was performed by independent blinded comparison by two nuclear medicine physicians assessing 65 pairs of SPECT/CT. Inter-observer agreement was tested by Cohen's kappa coefficient. For the quantitative analysis, two volumes of interest within the liver, VOI TUMOR , and VOI HEALTHY were manually delineated on the 166 Ho-only reconstruction and transferred to the co-registered 166 Ho-DI reconstruction. Absorbed dose within the resulting VOIs, and in the lungs (VOI LUNGS), was calculated based on the administered therapeutic activity. Results: The qualitative assessment showed no distinct clinical preference for either 166 Ho-only or 166 Ho-DI SPECT (kappa = 0.093). Quantitative analysis indicated that the mean absorbed dose difference between 166 Ho-DI and 166 Ho-only was − 2.00 ± 2.84 Gy (median 27 Gy; p value < 0.00001), − 5.27 ± 8.99 Gy (median 116 Gy; p value = 0.00035), and 0.80 ± 1.08 Gy (median 3 Gy; p value < 0.00001) for VOI HEALTHY, VOI TUMOR, and VOI LUNGS , respectively. The corresponding Pearson's correlation coefficient between 166 Ho-only and 166 Ho-DI for absorbed dose was 0.97, 0.99, and 0.82, respectively. Conclusion: The DI protocol enables automatic dosimetry with undiminished image quality and accuracy.

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Section: Study Populationmentioning

confidence: 99%

“…In previous work, van Rooij et al [9] demonstrated the technical feasibility of quantitative 166 Ho SPECT reconstructions in the presence of 99m Tc in a phantom study. These reconstructions were obtained using the in-house developed Monte Carlo SPEC T reconstruction software (UMCS).…”

Section: Introductionmentioning

confidence: 99%

Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

et al. 2020

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“…To minimize patient motion, 99m Tc-stannous phytate was administered while the patient remained on the SPECT/CT table in supine position. The optimal 166 Ho -99m Tc ratio, yielding a high accuracy in DI reconstruction, was previously empirically determined by van Rooij et al [9] in our institution, based on phantom data, and the resulting 5:1 166 Ho -99m Tc activity ratio was adopted for this study.…”

Section: Image Acquisitionmentioning

confidence: 99%

“…In previous work, van Rooij et al [9] demonstrated the technical feasibility of quantitative 166 Ho SPECT reconstructions in the presence of 99m Tc in a phantom study. These reconstructions were obtained using in-house developed Monte Carlo SPECT reconstruction software (UMCS).…”

Section: Introductionmentioning

confidence: 99%

Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

Stella

Braat

Lam

et al. 2020

Preprint

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Background Accurate dosimetry is essential in radioembolization. To this purpose, an automatic protocol for healthy liver dosimetry based on dual isotope (DI) SPECT imaging, combining holmium-166 ( 166 Ho)-microspheres and technetium-99m ( 99m Tc)-colloid, was developed: 166 Ho-microspheres used as scout and therapeutic particles and 99m Tc-colloid to identify the healthy liver. DI SPECT allows for an automatic and accurate estimation of absorbed doses, introducing true personalized dosimetry. However, photon crosstalk between isotopes can compromise image quality. This study investigates the effect of 99m Tc downscatter on 166 Ho dosimetry, by comparing 166 Ho-SPECT reconstructions of patient scans acquired before ( 166 Ho-only) and after additional administration of 99m Tc-colloid ( 166 Ho-DI). Results The 166 Ho-only and 166 Ho-DI scans were performed in short succession by injecting 99m Tc-colloid on the scanner table. To compensate for 99m Tc downscatter, its influence was accounted for in the DI image reconstruction using energy window-based scatter correction methods. The qualitative assessment was performed by independent blinded comparison by two nuclear medicine physicians assessing 65 pairs of SPECT/CT. Inter-observer agreement was tested by Cohen's kappa coefficient. For the quantitative analysis, two volumes of interest within the liver, VOI TUMOR and VOI HEALTHY , were manually delineated on the 166 Ho-only reconstruction and transferred to the co-registered 166 Ho-DI reconstruction. Absorbed dose within the resulting VOIs, and in the lungs (VOI LUNGS ), was calculated based on the administered therapeutic activity. The qualitative assessment showed no distinct clinical preference for either 166 Ho-only or 166 Ho-DI SPECT (kappa=0.093). Quantitative analysis indicated that the mean absorbed dose difference between 166 Ho-DI and 1 66 Ho-only was -2.00±2.84 Gy (median 27 Gy; p-value <0.00001), -5.27±8.99 Gy (median 116 Gy; p-value =0.00035) and 0.80±1.08 Gy (median 3 Gy; p-value <0.00001) for VOI HEALTHY , VOI TUMOR and VOI LUNGS respectively. The corresponding Pearson’s correlation coefficient between 166 Ho-only and 166 Ho-DI for absorbed dose was 0.97, 0.99 and 0.82, respectively. Conclusions The DI protocol enables automatic dosimetry with undiminished image quality and accuracy.

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“…Firstly, MRI-guided catheter-based vascular interventions are scarce and, to the best of our knowledge, no clinically available angiography catheters and guidewires are registered as MR-conditional for use at 3 Tesla (T) [18]. Additionally, previous studies into imaging 166 Ho microspheres with MRI [14][15][16] and SPECT [19,20] have mainly focused on the quantification once the microspheres are already lodged in the liver arterioles, i.e., in their final position. Ideally, MRI guidance would also be used to visualise the loss of signal caused by the microspheres in near real-time during administration, in order to be able to terminate the administration of microspheres if stasis or backflow occur.…”

Section: Introductionmentioning

confidence: 99%

Development of an MRI-Guided Approach to Selective Internal Radiation Therapy Using Holmium-166 Microspheres

Roosen

Arntz

Janssen

et al. 2021

Cancers

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Selective internal radiation therapy (SIRT) is a treatment modality for liver tumours during which radioactive microspheres are injected into the hepatic arterial tree. Holmium-166 (166Ho) microspheres used for SIRT can be visualized and quantified with MRI, potentially allowing for MRI guidance during SIRT. The purpose of this study was to investigate the MRI compatibility of two angiography catheters and a microcatheter typically used for SIRT, and to explore the detectability of 166Ho microspheres in a flow phantom using near real-time MRI. MR safety tests were performed at a 3 T MRI system according to American Society for Testing of Materials standard test methods. To assess the near real-time detectability of 166Ho microspheres, a flow phantom was placed in the MRI bore and perfused using a peristaltic pump, simulating the flow in the hepatic artery. Dynamic MR imaging was performed using a 2D FLASH sequence during injection of different concentrations of 166Ho microspheres. In the safety assessment, no significant heating (ΔTmax 0.7 °C) was found in any catheter, and no magnetic interaction was found in two out of three of the used catheters. Near real-time MRI visualization of 166Ho microsphere administration was feasible and depended on holmium concentration and vascular flow speed. Finally, we demonstrate preliminary imaging examples on the in vivo catheter visibility and near real-time imaging during 166Ho microsphere administration in an initial patient case treated with SIRT in a clinical 3 T MRI. These results support additional research to establish the feasibility and safety of this procedure in vivo and enable the further development of a personalized MRI-guided approach to SIRT.

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Simultaneous 166Ho/99mTc dual-isotope SPECT with Monte Carlo-based downscatter correction for automatic liver dosimetry in radioembolization

Cited by 15 publications

References 20 publications

Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

Quantitative 166Ho-microspheres SPECT derived from a dual-isotope acquisition with 99mTc-colloid is clinically feasible

Development of an MRI-Guided Approach to Selective Internal Radiation Therapy Using Holmium-166 Microspheres

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