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Establishing Updated Safety Standards for Independent 99 m Tc-MAA SPECT/CT Treatment Planning in Radioembolization.
- Source :
-
International journal of radiation oncology, biology, physics [Int J Radiat Oncol Biol Phys] 2024 Jul 15; Vol. 119 (4), pp. 1285-1296. Date of Electronic Publication: 2024 Jun 14. - Publication Year :
- 2024
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Abstract
- Purpose: Significant improvements within radioembolization imaging and dosimetry permit the development of an accurate and personalized pretreatment plan using technetium 99m-labeled macroaggregated albumin ( <superscript>99</superscript> <superscript>m</superscript> Tc-MAA) and single-photon emission computed tomography (SPECT) combined with anatomical CT (SPECT/CT). Despite these potential advantages, the clinical transition to pretreatment protocols with SPECT/CT is hindered by their unknown safety constraints. This study aimed to address this issue by establishing novel dose limits for <superscript>99</superscript> <superscript>m</superscript> Tc-MAA SPECT/CT to enable quantitative pretreatment planning.<br />Methods and Materials: Stratification criteria to determine images most viable for dosimetry analysis were created from a cohort of 85 patients. SPECT/CT, cone beam CT, and activity calculations derived from the local deposition method were used to create an accurate pretreatment protocol. Planar and SPECT/CT images were compared using linear regression and modified Bland-Altman analyses to convert accepted planar dose limits to SPECT/CT. To validate these new dose limits, activity calculations based on SPECT/CT were compared with those calculated with the body surface area and planar methods for three treatment plans.<br />Results: A total of 38 of 85 patients were deemed viable for dosimetry analysis. SPECT yielded greater lung shunt fractions (LSFs) than planar imaging when LSFs were <4.89%, whereas SPECT yielded lower LSFs than planar imaging when LSFs were >4.89%. Planar to SPECT/CT dose conversions were 0.76×, 0.70×, and 0.55× for the whole liver, normal liver, and lungs, respectively. Patients with SPECT LSFs ≤4.89% were safely treated with the direct application of planar lung dose limits. Activity calculations with the newly established SPECT/CT dose limits were greater than those of the body surface area method by a median range of 33.1% to 61.9% and were lower than planar-based activity calculations by a median range of 12.5% to 13.7% for the whole liver and by 29.4% to 32.2% for the normal liver.<br />Conclusions: This study demonstrated a safe method for translating dose limits from <superscript>99</superscript> <superscript>m</superscript> Tc-MAA planar imaging to SPECT/CT. A robust pretreatment protocol was further developed guided by the current knowledge in the field. Established SPECT/CT dose limits safely treated 97.5% of patients and permitted the application of independent pretreatment planning with <superscript>99</superscript> <superscript>m</superscript> Tc-MAA SPECT/CT.<br /> (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Subjects :
- Humans
Male
Female
Aged
Middle Aged
Radiotherapy Planning, Computer-Assisted methods
Radiotherapy Planning, Computer-Assisted standards
Radiopharmaceuticals
Aged, 80 and over
Body Surface Area
Cone-Beam Computed Tomography methods
Technetium Tc 99m Aggregated Albumin
Single Photon Emission Computed Tomography Computed Tomography methods
Embolization, Therapeutic methods
Liver Neoplasms radiotherapy
Liver Neoplasms diagnostic imaging
Subjects
Details
- Language :
- English
- ISSN :
- 1879-355X
- Volume :
- 119
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- International journal of radiation oncology, biology, physics
- Publication Type :
- Academic Journal
- Accession number :
- 38925768
- Full Text :
- https://doi.org/10.1016/j.ijrobp.2023.12.049