Treatment Modification of Yttrium-90 Radioembolization Based on Quantitative Positron Emission Tomography/CT Imaging

Chang, Ted T.; Bourgeois, Austin C.; Balius, A.; Pasciak, Alexander S.

doi:10.1016/j.jvir.2012.12.005

Cited by 18 publications

(14 citation statements)

References 11 publications

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“…Long clinical scan times of up to 45 min have been used to compensate for low true-coincidence rates in an effort to improve image quality (32). However, other authors have obtained acceptable image quality with scan times as short as 20 min (22).…”

Section: Image Qualitymentioning

confidence: 99%

“…Both Kennedy et al (40) and Dieudonne et al (41) have used 3D SPECT data following infusion of 99m Tc MAA translated into absorbed dose maps using DPK convolution. A number of authors have used DPK convolution as a tool to compute absorbed dose in patient and phantom studies using post-infusion imaging with 90 Y PET/CT (13, 18, 19, 32, 37, 42). In several cases, DPKs were used from published literature such as reported by Strigari et al (43) or Lanconelli et al (44).…”

Section: Y Pet/ct Dosimetrymentioning

confidence: 99%

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Radioembolization and the Dynamic Role of 90Y PET/CT

et al. 2014

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Before the advent of tomographic imaging, it was postulated that decay of 90 Y to the 0+ excited state of 90Zr may result in emission of a positron–electron pair. While the branching ratio for pair-production is small (~32 × 10−6), PET has been successfully used to image 90 Y in numerous recent patients and phantom studies. 90 Y PET imaging has been performed on a variety of PET/CT systems, with and without time-of-flight (TOF) and/or resolution recovery capabilities as well as on both bismuth-germanate and lutetium yttrium orthosilicate (LYSO)-based scanners. On all systems, resolution and contrast superior to bremsstrahlung SPECT has been reported. The intrinsic radioactivity present in LYSO-based PET scanners is a potential limitation associated with accurate quantification of 90 Y. However, intrinsic radioactivity has been shown to have a negligible effect at the high activity concentrations common in 90 Y radioembolization. Accurate quantification is possible on a variety of PET scanner models, with or without TOF, although TOF improves accuracy at lower activity concentrations. Quantitative 90 Y PET images can be transformed into 3-dimensional (3D) maps of absorbed dose based on the premise that the 90 Y activity distribution does not change after infusion. This transformation has been accomplished in several ways, although the most common is with the use of 3D dose-point-kernel convolution. From a clinical standpoint, 90 Y PET provides a superior post-infusion evaluation of treatment technical success owing to its improved resolution. Absorbed dose maps generated from quantitative PET data can be used to predict treatment efficacy and manage patient follow-up. For patients who receive multiple treatments, this information can also be used to provide patient-specific treatment-planning for successive therapies, potentially improving response. The broad utilization of 90 Y PET has the potential to provide a wealth of dose–response information, which may lead to development of improved radioembolization treatment-planning models in the future.

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Section: Image Qualitymentioning

confidence: 99%

Section: Y Pet/ct Dosimetrymentioning

confidence: 99%

Radioembolization and the Dynamic Role of 90Y PET/CT

et al. 2014

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“…For enabling the evaluation of radiation absorbed doses in tumorous and healthy liver tissues, posttreatment imaging of the 90 Y microsphere distribution has recently gained interest (3)(4)(5).…”

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confidence: 99%

Quantitative Monte Carlo–Based ⁹⁰Y SPECT Reconstruction

et al. 2013

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The evaluation of radiation absorbed doses in tumorous and healthy tissues is of increasing interest for 90 Y microsphere radioembolization of liver malignancies. The objectives of this work were to introduce and validate a new reconstruction method for quantitative 90 Y bremsstrahlung SPECT to improve posttreatment dosimetry. Methods: A fast Monte Carlo simulator was adapted for 90 Y and incorporated into a statistical reconstruction algorithm (SPECT-MC). Photon scatter and attenuation for all photons sampled from the full 90 Y energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy-and distance-dependent collimator-detector response was modeled with precalculated convolution kernels. The National Electrical Manufacturers Association 2007/International Electrotechnical Commission 2008 image quality phantom was used to quantitatively evaluate the performance of SPECT-MC in comparison with those of state-of-the-art clinical SPECT reconstruction and PET. The liver radiation absorbed doses estimated by SPECT, PET, and SPECT-MC were evaluated in 5 patients consecutively treated with radioembolization. Results: In comparison with state-of-the-art clinical 90 Y SPECT reconstruction, SPECT-MC substantially improved image contrast (e.g., from 25% to 88% for the 37-mm sphere) and decreased the mean residual count error in the lung insert (from 73% to 15%) at the cost of higher image noise. Image noise and the mean count error were lower for SPECT-MC than for PET. Image contrast was higher in the larger spheres (diameter of $28 mm) but lower in the smaller spheres (#22 mm) for SPECT-MC than for PET. In the clinical study, mean absorbed dose estimates in liver regions with high absorbed doses were consistently higher for SPECT-MC than for SPECT (P 5 0.0625) and consistently higher for SPECT-MC than for PET (P 5 0.0625). Assessment of the 90 Y microsphere distribution can be performed by imaging bremsstrahlung photons with a SPECT camera or by imaging annihilation photons with a PET camera. Posttreatment dosimetry with 90 Y PET has advantages over SPECT, mainly because of higher resolution and image contrast (6,7). However, the low positron branch (32 · 10 26 ) in 90 Y decay requires a stateof-the-art lutetium-(yttrium)-orthosilicate time-of-flight PET/CT scanner to obtain images with sufficiently high quantitative accuracy for dosimetry purposes (8,9). Posttreatment imaging with a standard SPECT/CT system may be a more widely available and cost-effective option for most centers, but the image quality (IQ) of state-of-the-art clinical 90 Y bremsstrahlung SPECT is still limited (7). The wide range (0-2.3 MeV) and continuous nature of the 90 Y bremsstrahlung photon spectrum prohibit the use of simple energy window-based scatter rejection and correction techniques, hinder attenuation correction based on single-photon energy, and require compensation for collimator-and detector-related imagedegrading effects, such as collimator scatter, lead x-rays, septal penetration, camera (back)scatter, an...

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“…Since the widespread use of post-radioembolization 90 Y PET/CT, there has been an interest in utilizing this imaging data to improve patient therapy. While multimodality treatment utilizing 90 Y radioembolization has not been widely studied, several authors have attempted the use of 90 Y PET/CT to provide multistage patient-specific 90 Y treatments with positive outcomes [14, 15]. …”

Section: Introductionmentioning

confidence: 99%

Computational simulation of the predicted dosimetric impact of adjuvant yttrium-90 PET/CT-guided percutaneous ablation following radioembolization

et al. 2016

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Background 90Y PET/CT post-radioembolization imaging has demonstrated that the distribution of 90Y in a tumor can be non-uniform. Using computational modeling, we predicted the dosimetric impact of post-treatment 90Y PET/CT-guided percutaneous ablation of the portions of a tumor receiving the lowest absorbed dose. A cohort of fourteen patients with non-resectable liver cancer previously treated using 90Y radioembolization were included in this retrospective study. Each patient exhibited potentially under-treated areas of tumor following treatment based on quantitative 90Y PET/CT. 90Y PET/CT was used to guide electrode placement for simulated adjuvant radiofrequency ablation in areas of tumor receiving the lowest dose. The finite element method was used to solve Penne’s bioheat transport equation, coupled with the Arrhenius thermal cell-death model to determine 3D thermal ablation zones. Tumor and unablated tumor absorbed-dose metrics (average dose, D50, D70, D90, V100) following ablation were compared, where D70 is the minimum dose to 70% of tumor and V100 is the fractional tumor volume receiving more than 100 Gy.ResultsCompared to radioembolization alone, 90Y radioembolization with adjuvant ablation was associated with predicted increases in all tumor dose metrics evaluated. The mean average absorbed dose increased by 11.2 ± 6.9 Gy. Increases in D50, D70, and D90 were 11.0 ± 6.9 Gy, 13.3 ± 10.9 Gy, and 11.8 ± 10.8 Gy, respectively. The mean increase in V100 was 7.2 ± 4.2%. All changes were statistically significant (P < 0.01). A negative correlation between pre-ablation tumor volume and D50, average dose, and V100 was identified (ρ < − 0.5, P < 0.05) suggesting that adjuvant radiofrequency ablation may be less beneficial to patients with large tumor burdens.ConclusionsThis study has demonstrated that adjuvant 90Y PET/CT-guided radiofrequency ablation may improve tumor absorbed-dose metrics. These data may justify a prospective clinical trial to further evaluate this hybrid approach.

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Treatment Modification of Yttrium-90 Radioembolization Based on Quantitative Positron Emission Tomography/CT Imaging

Cited by 18 publications

References 11 publications

Radioembolization and the Dynamic Role of 90Y PET/CT

Radioembolization and the Dynamic Role of 90Y PET/CT

Quantitative Monte Carlo–Based ⁹⁰Y SPECT Reconstruction

Computational simulation of the predicted dosimetric impact of adjuvant yttrium-90 PET/CT-guided percutaneous ablation following radioembolization

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Treatment Modification of Yttrium-90 Radioembolization Based on Quantitative Positron Emission Tomography/CT Imaging

Cited by 18 publications

References 11 publications

Radioembolization and the Dynamic Role of 90Y PET/CT

Radioembolization and the Dynamic Role of 90Y PET/CT

Quantitative Monte Carlo–Based 90Y SPECT Reconstruction

Computational simulation of the predicted dosimetric impact of adjuvant yttrium-90 PET/CT-guided percutaneous ablation following radioembolization

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Quantitative Monte Carlo–Based ⁹⁰Y SPECT Reconstruction