Impact of respiratory motion and acquisition settings on <scp>SPECT</scp> liver dosimetry for radioembolization

Bastiaannet, Remco; Viergever, Max A.; Jong, Hugo W. A. M. de

doi:10.1002/mp.12483

Cited by 32 publications

(35 citation statements)

References 52 publications

(104 reference statements)

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“…Bastiaannet et al. demonstrated that respiration is the predominant degrading effect on 90 Y SPECT image quantification and can be alleviated through respiratory gating 25. A similar conclusion was presented by Siman et al.…”

Section: Discussionsupporting

confidence: 78%

SPECT/CT image‐based dosimetry for Yttrium‐90 radionuclide therapy: Application to treatment response

Potrebko

Shridhar

Biagioli

et al. 2018

J Applied Clin Med Phys

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This work demonstrates the efficacy of voxel‐based 90Y microsphere dosimetry utilizing post‐therapy SPECT/CT imaging and applies it to the prediction of treatment response for the management of patients with hepatocellular carcinoma (HCC). A 90Y microsphere dosimetry navigator (RapidSphere) within a commercial platform (Velocity, Varian Medical Systems) was demonstrated for three microsphere cases that were imaged using optimized bremsstrahlung SPECT/CT. For each case, the 90Y SPECT/CT was registered to follow‐up diagnostic MR/CT using deformable image registration. The voxel‐based dose distribution was computed using the local deposition method with known injected activity. The system allowed the visualization of the isodose distributions on any of the registered image datasets and the calculation of dose‐volume histograms (DVHs). The dosimetric analysis illustrated high local doses that are characteristic of blood‐flow directed brachytherapy. In the first case, the HCC mass demonstrated a complete response to treatment indicated by a necrotic region in follow‐up MR imaging. This result was dosimetrically predicted since the gross tumor volume (GTV) was well covered by the prescription isodose volume (V150 Gy = 85%). The second case illustrated a partial response to treatment which was characterized by incomplete necrosis of an HCC mass and a remaining area of solid enhancement in follow‐up MR imaging. This result was predicted by dosimetric analysis because the GTV demonstrated incomplete coverage by the prescription isodose volume (V470 Gy = 18%). The third case demonstrated extrahepatic activity. The dosimetry indicated that the prescription (125 Gy) isodose region extended outside of the liver into the duodenum (178 Gy maximum dose). This was predictive of toxicity as the patient later developed a duodenal ulcer. The ability to predict outcomes and complications using deformable image registration, calculated isodose distributions, and DVHs, points to the clinical utility of patient‐specific dose calculations for 90Y radioembolization treatment planning.

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Section: Discussionsupporting

confidence: 78%

SPECT/CT image‐based dosimetry for Yttrium‐90 radionuclide therapy: Application to treatment response

Potrebko

Shridhar

Biagioli

et al. 2018

J Applied Clin Med Phys

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“…In the current protocol, patient breathing was not accounted for. Patient breathing is known to result in an underestimation of actual activity depositions and blur SPECT/CT images [20]. This issue may be resolved by applying breath gating during image acquisition, although this feature is currently not supported on our SPECT/CT imaging devices.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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Background: Intrahepatic dosimetry is paramount to optimize radioembolization treatment accuracy using radioactive holmium-166 microspheres (166 Ho). This requires a practical protocol that combines quantitative imaging of microsphere distribution with automated and robust delineation of the volumes of interest. To this end, we propose a dual isotope single photon emission computed tomography (SPECT) protocol based on 166 Ho therapeutic microspheres and technetium-99 m (99m Tc) stannous phytate, which accumulates in healthy liver tissue. This protocol may allow accurate and automatic estimation of tumor-absorbed dose and healthy liver-absorbed dose. The current study focuses on a Monte Carlo-based reconstruction framework that inherently corrects for scatter crosstalk between the 166 Ho and 99m Tc imaging. To demonstrate the feasibility of the method, it is evaluated with realistic phantom experiments and patient data. Methods: The Utrecht Monte Carlo System (UMCS) was extended to include detailed modeling of crosstalk interactions between 99m Tc and 166 Ho. First, 99m Tc images were reconstructed including energy window-based corrections for 166 Ho downscatter. Next, 99m Tc downscatter in the 81-keV 166 Ho window was Monte Carlo simulated to allow quantitative reconstruction of the 166 Ho images. The accuracy of the 99m Tc-downscatter modeling was evaluated by comparing measurements with simulations. In addition, the ratio between 99m Tc and 166 Ho yielding the best 166 Ho dose estimates was established and the quantitative accuracy was reported. Results: Given the same level of activity, 99m Tc contributes twice as many counts to the 81-keV window than 166 Ho, and four times as many counts to the 140-keV window, applying a 166 Ho/ 99m Tc ratio of 5:1 yielded a high accuracy in both 166 Ho and 99m Tc reconstruction. Phantom experiments revealed that the accuracy of quantitative 166 Ho activity recovery was reduced by 10% due to the presence of 99m Tc. Twenty iterations (8 subsets) of the SPECT/CT reconstructions were considered feasible for clinical practice. Applicability of the proposed protocol was shown in a proof-of-concept case. Conclusion: A novel 166 Ho/ 99m Tc dual-isotope protocol for automatic dosimetry compensates accurately for downscatter and allows for the addition of 99m Tc without compromising 166 Ho SPECT image quality.

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“…8b) and tumor ( Fig. 8a) VOIs were determined on SPECT images by setting a threshold such that the volume of VOIs equaled to that of corresponding VOIs from the contrast HCT-EX image [26]. The tumor and NL VOIs obtained from these methods can then be used to calculate TNR using Eq.…”

Section: Tnr Estimationmentioning

confidence: 99%

CT Protocols for Attenuation Correction and Segmentation in 99mTc-MAA SPECT/CT for 90Y Radioembolization Treatment Planning – a Simulation Study

Lü¹,

Mok²

2020

Preprint

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Background Conventional 99mTc-macroaggregated albumin (99mTc-MAA) planar scintigraphy overestimates lung shunt fraction (LSF) as compared to SPECT/CT in 90Y radioembolization treatment planning. However, the respiratory motion artifact due to the temporal mismatch between static SPECT and helical CT (HCT) may compromise the SPECT quantitation accuracy by incorrect attenuation correction (AC) and volume-of-interest segmentation. The goal of this study is to systematically assess different AC and segmentation protocols for LSF, tumor-to-normal liver (TNR), organ absorbed dose and injected activity (IA) estimation in 99mTc-MAA SPECT/CT.Methods The 4D XCAT phantom was used to simulate 10 patient anatomies with 99mTc-MAA distribution based on the clinical data, each with LSF of 5%, 10%, 15% and 20%, axial respiratory motion of 2 cm, different TNR and tumor size. An analytical projector for low energy high resolution parallel-hole collimator was used to simulate realistic noisy planar acquisitions, and 128 projections over 360o for SPECT, both modeling attenuation, scatter and geometric collimator-detector-response. Five attenuation maps, i.e., (i) HCT at end-inspiration (HCT-IN), (ii) HCT at mid-respiration (HCT-MID), (iii) HCT at end-expiration (HCT-EX), (iv) cine averaged CT (CACT) and (v) interpolated average CT (IACT) were applied for SPECT AC and segmentation in LSF, dosimetric and IA evaluation. Mid-respiratory phases were also extracted from CACT/IACT for VOI segmentation while CACT/IACT were used for AC, i.e., hybrid CT protocols.Results For LSF estimation, SPECT/CACT has the least absolute errors. Planar significantly overestimates LSF and lung absorbed dose compared to SPECT especially for LSF of 5%. SPECT-based is better than CT-based segmentation in TNR estimation. There is no statistically significant difference for different CT protocols for TNR, normal liver and tumor absorbed dose estimation. Hybrid CTs and HCT-MID performed the best for IA especially for higher LSF.Conclusions 99mTc-MAA SPECT/CT with an appropriate choice of CT protocol for AC and segmentation is superior to planar in LSF and lung absorbed dose estimation. The 4D CT protocols are recommended for AC and segmentation to alleviate respiratory artifacts and improve quantitation accuracy in 90Y radioembolization treatment planning. HCT-EX would also be a recommended choice if 4D CT is not available.

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Impact of respiratory motion and acquisition settings on SPECT liver dosimetry for radioembolization

Cited by 32 publications

References 52 publications

SPECT/CT image‐based dosimetry for Yttrium‐90 radionuclide therapy: Application to treatment response

SPECT/CT image‐based dosimetry for Yttrium‐90 radionuclide therapy: Application to treatment response

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

CT Protocols for Attenuation Correction and Segmentation in 99mTc-MAA SPECT/CT for 90Y Radioembolization Treatment Planning – a Simulation Study

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