Characterization of <sup>90</sup>Y‐<scp>SPECT</scp>/<scp>CT</scp> self‐calibration approaches on the quantification of voxel‐level absorbed doses following <sup>90</sup>Y‐microsphere selective internal radiation therapy

Balagopal, Anjali; Kappadath, S. Cheenu

doi:10.1002/mp.12695

Cited by 20 publications

(27 citation statements)

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“…The details of this method and its benchmarking against other voxelized dose calculations, such as kernelbased methods and Monte Carlo computations, have been published previously. 6,8,9 As discussed above and previously, 6,24 90 Y-Sureplan uses a self-calibration to obtain quantitative SPECT/CT images with SPECT activity concentration in each voxel (Bq/mL instead of counts/mL). The liver volume was chosen for this self-calibration due to the fact that most counts outside the liver volume are likely erroneous artifacts of SPECT reconstruction and difficulty in 90 Y bremsstrahlung scatter correction.…”

Section: G Voxel Dosimetry: Maa and 90 Ymentioning

confidence: 99%

“…The two commonly used dosimetry models that improve upon MIRD are the partition model (PM) [4][5][6] and voxel dosimetry. [7][8][9][10][11] The imaging modalities primarily used for 90 Y SIRT dosimetry are 99m Tc-macroaggregated albumin (MAA) single photon emission computed tomography/CT (SPECT/CT) for treatment planning 10 and 90 Y-SPECT/CT 7 or 90 Y-positron emission tomography/CT (PET/CT) 11 for treatment verification. It has previously been reported that differences may exist between either planning (MAA) and treatment ( 90 Y) images or 90 Y-SPECT and 90 Y-PET that can lead to differences in dose calculation.…”

Section: Introductionmentioning

confidence: 99%

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Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

et al. 2020

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Purpose: 99m Tc-MAA-SPECT/CT may be used in 90 Y-glass microsphere radioembolization treatment planning to assess perfused liver volumes and absorbed dose distributions. The partition model (PM) offers a more detailed planning dosimetry option beyond the single-compartment model more traditionally used in 90 Y radioembolization. As 90 Y radioembolization treatments shift toward activities and doses that aim to achieve tumor control, accurate and reliable treatment planning dosimetry for both tumors and normal liver (NL) becomes more critical. In this work, we explore the accuracy and precision of 90 Y dosimetry predictions from pretherapy 99m Tc-MAA and PM. Methods: Both PM and voxel dosimetry models were used to calculate tumor and NL mean doses using both planning 99m Tc-MAA and verification 90 Y-SPECT/CT in this retrospective analysis of hepatocellular carcinoma cases treated with glass microspheres (NCT01900002, n = 32). Linear regression models were developed at first access, and then later correct, the estimates by (a) 99m Tc-MAA for 90 Y voxel dosimetry and (b) 99m Tc-MAA PM for voxel dosimetry, separately for both tumors and NL. Bland-Altman analysis was then used to evaluate the accuracy and precision of the regression model predictions with the mean bias and 95% prediction intervals (PI, AE1.96σ). Two categories of cases were stratified (catheter matched vs catheter unmatched) by establishing the level of 99m Tc-MAA and 90 Y catheter position alignment. Only catheter-matched cases were included in the 99m Tc-MAA vs 90 Y voxel dosimetry comparison, while all cases were used to compare dosimetry models (PM vs voxel). Results: Half (16/32) of cases were deemed catheter matched. 99m Tc-MAA could reliably predict NL doses in catheter-matched cases after application of the linear model, with mean bias (PI) of −1% (AE31%). PM was equivalent to voxel dosimetry for NL doses with mean bias (PI) of 0% (AE1%). Even among catheter-matched cases, 99m Tc-MAA planning for 90 Y tumor voxel doses was poor, overestimating dose by an average of nearly 40%. Upon application of the linear model, 99m Tc-MAA predictions for 90 Y tumor voxel dose were only minimally biased (−4%) but possessed very large PI (AE104%). PM predictions for tumor voxel dose using the linear model also showed small bias (−6%) but maintained similarly high PI of AE90%. Cases with tumors representing a large majority (>80%) of the total tumor volume demonstrated the best scenarios for 99m Tc-MAA and PM tumor dose predictions, with mean biases (PI) of −3% (AE53%) and −4% (AE21%), respectively. Conclusion: The unconditional use of 99m Tc-MAA to predict 90 Y dosimetry across all cases is not recommended due to: (a) demonstrated the risk of unmatched catheter positions between procedures, and (b) large bias and uncertainty in 99m Tc-MAA predictions in cases with matched catheter locations. However, NL voxel dose predictions with 99m Tc-MAA are clinically viable and either PM or voxel dosimetry can be used to produce equivalent predictions. Both 99m Tc-MAA a...

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Section: G Voxel Dosimetry: Maa and 90 Ymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

et al. 2020

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“…This method avoids counts due to image artifacts. The motivation for using directly the patients’ liver uptake to calculate the CF is that due to the proximity of the treatment to the target area where the 90 Y microspheres are deposited predominantly in the liver, the 90 Y activity can be determined with high accuracy . Calibration curves were generated using linear regression analysis to derive the relationship between patient administered activity and reconstructed counts.…”

Section: Methodsmentioning

confidence: 99%

⁹⁰Y SPECT/CT quantitative study and comparison of uptake with pretreatment ^99 mTc‐MAA SPECT/CT in radiomicrosphere therapy

Debebe

Adjouadi

Güleç

et al. 2019

J Applied Clin Med Phys

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IntroductionYttrium‐90 (90Y) microsphere post‐treatment imaging reflects the true distribution characteristics of microspheres in the tumor and liver compartments. However, due to its decay spectra profile lacking a pronounced photopeak, the bremsstrahlung imaging for 90Y has inherent limitations. The absorbed dose calculations for 90Y microspheres radiomicrosphere therapy (RMT) sustain a limitation due to the poor quality of 90Y imaging. The aim of this study was to develop quantitative methods to improve the post‐treatment 90Y bremsstrahlung single photon emission tomography (SPECT)/computed tomography (CT) image analysis for dosimetric purposes and to perform a quantitative comparison with the 99mTc‐MAA SPECT/CT images, which is used for theranostics purposes for liver and tumor dosimetry.MethodsPre and post‐treatment SPECT/CT data of patients who underwent RMT for primary or metastatic liver cancer were acquired. A Jasczak phantom with eight spherical inserts of various sizes was used to obtain optimal iteration number for the contrast recovery algorithm for improving 90Y bremsstrahlung SPECT/CT images. Comparison of uptake on 99mTc‐MAA and 90Y microsphere SPECT/CT images was assessed using tumor to healthy liver ratios (TLRs). The voxel dosimetry technique was used to estimate absorbed doses. Absorbed doses within the tumor and healthy part of the liver were also investigated for correlation with administered activity.ResultsImprovement in CNR and contrast recovery coefficients on patient and phantom 90Y bremsstrahlung SPECT/CT images respectively were achieved. The 99mTc‐MAA and 90Y microspheres SPECT/CT images showed significant uptake correlation (r = 0.9, P = 0.05) with mean TLR of 9.4 ± 9.2 and 5.0 ± 2.2, respectively. The correlation between the administered activity and tumor absorbed dose was weak (r = 0.5, P > 0.05), however, healthy liver absorbed dose increased with administered activity (r = 0.8, P = 0.0).ConclusionsThis study demonstrated correlation in mean TLR between 99mTc‐MAA and 90Y microsphere SPECT/CT.

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“…LDM users argue that the image voxel size and point spread function (PSF) of the imaging system provide enough spatial blurring of the image to represent the dose spread of the β ‐ from 90 Y, and therefore, convolution with a DPK is unnecessary . Balagopal and Kappadath recently validated the LDM option of MIM SurePlan™ with 90 Y SPECT images against Monte Carlo simulations . In this study, we compared results from the voxel S value option of this commercial dosimetry software — MIM SurePlan™ LiverY90 (MIM Software, Inc., Cleveland, OH) — to a MATLAB‐based algorithm developed in‐house for the purpose of commissioning the commercial software for clinical use.…”

Section: Introductionmentioning

confidence: 99%

“…10 Balagopal and Kappadath recently validated the LDM option of MIM SurePlan TM with 90 Y SPECT images against Monte Carlo simulations. 22 In this study, we compared results from the voxel S value option of this commercial dosimetry software -MIM SurePlan TM LiverY90 (MIM Software, Inc., Cleveland, OH)to a MATLAB-based algorithm developed in-house for the purpose of commissioning the commercial software for clinical use.…”

Section: Introductionmentioning

confidence: 99%

Validation of post‐treatment PET‐based dosimetry software for hepatic radioembolization of Yttrium‐90 microspheres

et al. 2019

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Purpose Yttrium‐90 (90Y) microsphere radioembolization enables selective internal radiotherapy for hepatic malignancies. Currently, there is no standard postdelivery imaging and dosimetry of the microsphere distribution to verify treatment. Recent studies have reported utilizing the small positron yield of 90Y (32 ppm) with positron emission tomography (PET) to perform treatment verification and dosimetry analysis. In this study, we validated a commercial dosimetry software, MIM SurePlan™ LiverY90 (MIM Software Inc., Cleveland, OH), for clinical use. Methods A MATLAB‐based algorithm for 90Y PET‐based dosimetry was developed in‐house and validated for the purpose of commissioning the commercial software. The algorithm is based on voxel S values and dosimetry formalism reported in MIRD Pamphlet 17. We validated the in‐house algorithm to establish it as the ground truth by comparing results from a digital point phantom and a digital uniform cylinder to manual calculations. Once we validated our in‐house MATLAB‐based algorithm, we used it to perform acceptance testing and commissioning of the commercial dosimetry software, MIM SurePlan, which uses the same dosimetry formalism. A 0.4 cm/5% gamma test was performed on PET‐derived dose maps from each algorithm of uniform digital and nonuniform physical phantoms filled with 90Y chloride solution. Average dose (Davg) and minimum dose to 70% (D70) of a given volume of interest (VOI) were compared for the digital phantom, the physical phantom, and five patient cases (27 tumor VOIs), representing different clinical scenarios. Results The gamma‐pass rates were 97.26% and 97.66% for the digital and physical phantoms, respectively. The differences between Davg and D70 were 0.076% and 0.10% for the digital phantom, respectively, and <5.2% for various VOIs in the physical phantom. In the clinical cases, 96.3% of the VOIs had a difference <5% for Davg, and 88.9% of the VOIs had a difference <5% for D70. Conclusions Dose calculation results from MIM SurePlan were found to be in good agreement with our in‐house algorithm. This indicates that MIM SurePlan performs as it should and, hence, can be deemed accepted and commissioned for clinical use for post‐implant PET‐based dosimetry of 90Y radioembolization.

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Characterization of ⁹⁰Y‐SPECT/CT self‐calibration approaches on the quantification of voxel‐level absorbed doses following ⁹⁰Y‐microsphere selective internal radiation therapy

Cited by 20 publications

References 18 publications

Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

⁹⁰Y SPECT/CT quantitative study and comparison of uptake with pretreatment ^99 mTc‐MAA SPECT/CT in radiomicrosphere therapy

Validation of post‐treatment PET‐based dosimetry software for hepatic radioembolization of Yttrium‐90 microspheres

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Characterization of 90Y‐SPECT/CT self‐calibration approaches on the quantification of voxel‐level absorbed doses following 90Y‐microsphere selective internal radiation therapy

Cited by 20 publications

References 18 publications

Planning dosimetry for 90Y radioembolization with glass microspheres: Evaluating the fidelity of 99mTc‐MAA and partition model predictions

Planning dosimetry for 90Y radioembolization with glass microspheres: Evaluating the fidelity of 99mTc‐MAA and partition model predictions

90Y SPECT/CT quantitative study and comparison of uptake with pretreatment 99 mTc‐MAA SPECT/CT in radiomicrosphere therapy

Validation of post‐treatment PET‐based dosimetry software for hepatic radioembolization of Yttrium‐90 microspheres

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Characterization of ⁹⁰Y‐SPECT/CT self‐calibration approaches on the quantification of voxel‐level absorbed doses following ⁹⁰Y‐microsphere selective internal radiation therapy

Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

Planning dosimetry for ⁹⁰Y radioembolization with glass microspheres: Evaluating the fidelity of ^99mTc‐MAA and partition model predictions

⁹⁰Y SPECT/CT quantitative study and comparison of uptake with pretreatment ^99 mTc‐MAA SPECT/CT in radiomicrosphere therapy