Hepatocellular Carcinoma Tumor Dose Response After 90Y-radioembolization With Glass Microspheres Using 90Y-SPECT/CT-Based Voxel Dosimetry

Kappadath, S Cheenu; Mikell, Justin; Balagopal, Anjali; Baladandayuthapani, Veerabhadran; Kaseb, Ahmed O.; Mahvash, Armeen

doi:10.1016/j.ijrobp.2018.05.062

Cited by 83 publications

(68 citation statements)

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“…For many years, SIRT has been primarily a palliative treatment with relatively low administered activity, so large uncertainties in absorbed dose calculations have been clinically acceptable. However, recent reports on the correlation of tumor absorbed dose with tumor response and patient survival have demonstrated the potential therapeutic benefit of SIRT beyond palliation . Due, in part to improved dosimetry models, the practice of SIRT is evolving to use higher prescribed activity to deliver tumor doses with curative intent.…”

Section: Introductionmentioning

confidence: 99%

Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

et al. 2019

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Purpose Current treatment planning for 90Y radioembolization estimates lung mean dose (LMD) by measuring the lung shunt fraction (LSF) from 99mTc‐macroaggregated albumin (MAA) planar imaging and assuming a 1‐kg lung mass. This methodology, however, overestimates LSF and LMD and could therefore unnecessarily limit the dose to target volume(s). We propose an improved LMD calculation that derives LSF from 99mTc‐MAA SPECT/CT and the patient‐specific lung mass from diagnostic chest CT. Furthermore, we investigated the errors in lung mass, LSF, and LMD arising from contour variability in patient data in order to estimate the precision of our proposed methodology. Methods Our proposed LMD (LMDnew) calculation consisted of the following steps: (a) estimate liver counts from the MAA SPECT/CT liver contour; (b) estimate total lung counts by multiplying density (counts/g) from the MAA SPECT/CT left‐lung contour by the total lung mass (g) from the diagnostic CT lung contours; (c) compute LSFnew from liver and lung counts; (d) calculate LMDnew using LSFnew and the total lung mass from the diagnostic CT (Mnew). LMDnew, LSFnew, and Mnew estimates were compared to standard model values (LMDclin, LSFclin, and 1 kg, respectively) in 52 consecutive patients with hepatocellular carcinoma who underwent radioembolization using 90Y glass microspheres. The precision of our methodology was quantified by varying lung and liver contours in the same patient population and calculating the resulting relative errors in the liver count, lung count, and lung mass measurements. Results The median Mnew was 839 g (range, 550–1178 g) for men and 731 g (range, 548–869 g) for women. The median LSFnew was 0.02 (range, 0.01–0.11), while the median LMDnew was 4.9 Gy (range, 0.3–25.5 Gy). Mnew, LSFnew, and LMDnew were significantly lower than Mclin, LSFclin, and LMDclin, with respective relative mean (±SD) differences of −20% (±16%) for Mnew, −63% (±15%) for LSFnew, and −53% (±23%) for LMDnew. The estimated 1‐sigma uncertainties in Mnew, LSFnew, and LMDnew were 9%, 10%, and 13%, respectively. Conclusions We derived a method to calculate lung mass and LSF using routinely available diagnostic chest CT and 99mTc‐MAA SPECT/CT. More importantly, we systematically quantified the errors in our measurements to establish the precision of the estimated lung dose (13%). The proposed methodology provides a more accurate LMD and an estimate of its precision, which will improve treatment and retreatment planning for 90Y radioembolizations.

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Section: Introductionmentioning

confidence: 99%

Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

et al. 2019

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“…These are not reflections of the inaccuracy of the dose calculation method, but rather a characteristic limitation of the imaging modality itself. Regardless, many have found correlations between dose calculated on 90 Y PET and clinical outcomes, specifically, individual lesion response . Optimizing count recovery for 90 Y post‐radioembolization imaging remains an area of active and future research and is beyond the scope of this manuscript.…”

Section: Discussionmentioning

confidence: 98%

“…Regardless, many have found correlations between dose calculated on 90 Y PET and clinical outcomes, specifically, individual lesion response. 8,9,13,14 Optimizing count recovery for 90 Y post-radioembolization imaging remains an area of active and future research and is beyond the scope of this manuscript.…”

Section: Discussionmentioning

confidence: 99%

“…Extending post‐procedural imaging beyond quality control and toward quantitative dosimetry can offer significant clinical utility to users of 90 Y microspheres. Numerous studies using voxel‐based dosimetry have reported that dosimetric quantities, such as D avg and D 70 , derived from post‐radioembolization PET images can predict clinical outcomes on a lesion‐by‐lesion basis . Knowledge of a lesion's potential response or progression can help guide salvage therapy much sooner than what clinical workflows currently allow…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies using voxel-based dosimetry have reported that dosimetric quantities, such as D avg and D 70 , derived from post-radioembolization PET images can predict clinical outcomes on a lesion-by-lesion basis. 1,[8][9][10][11][12][13][14] Knowledge of a lesion's potential response or progression can help guide salvage therapy much sooner than what clinical workflows currently allow. 12,15 Until recently, the dosimetry calculations and analysis of post-radioembolization images had to be performed using inhouse developed algorithms, rendering it unsuitable for a seamless clinical workflow.…”

Section: Introductionmentioning

confidence: 99%

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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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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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Hepatocellular Carcinoma Tumor Dose Response After 90Y-radioembolization With Glass Microspheres Using 90Y-SPECT/CT-Based Voxel Dosimetry

Cited by 83 publications

References 40 publications

Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

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

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

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Hepatocellular Carcinoma Tumor Dose Response After 90Y-radioembolization With Glass Microspheres Using 90Y-SPECT/CT-Based Voxel Dosimetry

Cited by 83 publications

References 40 publications

Calculation of lung mean dose and quantification of error for 90Y‐microsphere radioembolization using 99mTc‐MAA SPECT/CT and diagnostic chest CT

Calculation of lung mean dose and quantification of error for 90Y‐microsphere radioembolization using 99mTc‐MAA SPECT/CT and diagnostic chest CT

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

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

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Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

Calculation of lung mean dose and quantification of error for ⁹⁰Y‐microsphere radioembolization using ^99mTc‐MAA SPECT/CT and diagnostic chest CT

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