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Ivashchenko OV, O'Doherty J, Hardiansyah D, Cremonesi M, Tran-Gia J, Hippeläinen E, Stokke C, Grassi E, Sandström M, Glatting G. Time-Activity data fitting in molecular Radiotherapy: Methodology and pitfalls. Phys Med 2024; 117:103192. [PMID: 38052710 DOI: 10.1016/j.ejmp.2023.103192] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 10/18/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023] Open
Abstract
Absorbed radiation doses are essential in assessing the effects, e.g. safety and efficacy, of radiopharmaceutical therapy (RPT). Patient-specific absorbed dose calculations in the target or the organ at risk require multiple inputs. These include the number of disintegrations in the organ, i.e. the time-integrated activities (TIAs) of the organs, as well as other parameters describing the process of radiation energy deposition in the target tissue (i.e. mean energy per disintegration, radiation dose constants, etc). TIAs are then estimated by incorporating the area under the radiopharmaceutical's time-activity curve (TAC), which can be obtained by quantitative measurements of the biokinetics in the patient (typically based on imaging data such as planar scintigraphy, SPECT/CT, PET/CT, or blood and urine samples). The process of TAC determination/calculation for RPT generally depends on the user, e.g., the chosen number and schedule of measured time points, the selection of the fit function, the error model for the data and the fit algorithm. These decisions can strongly affect the final TIA values and thus the accuracy of calculated absorbed doses. Despite the high clinical importance of the TIA values, there is currently no consensus on processing time-activity data or even a clear understanding of the influence of uncertainties and variations in personalised RPT dosimetry related to user-dependent TAC calculation. As a first step towards minimising site-dependent variability in RPT dosimetry, this work provides an overview of quality assurance and uncertainty management considerations of the TIA estimation.
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Affiliation(s)
- Oleksandra V Ivashchenko
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, the Netherlands.
| | - Jim O'Doherty
- Siemens Medical Solutions, Malvern, PA, United States of America; Department of Radiology & Radiological Science, Medical University of South Carolina, Charleston, SC, United States of America; Radiography & Diagnostic Imaging, University College Dublin, Dublin, Ireland
| | - Deni Hardiansyah
- Medical Physics and Biophysics Division, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia; Research Collaboration Centre for Theranostic Radiopharmaceuticals, BRIN, Bandung, Indonesia
| | - Marta Cremonesi
- Unit of Radiation Research, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Eero Hippeläinen
- Department of Clinical Physiology and Nuclear Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Caroline Stokke
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway
| | - Elisa Grassi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | | | - Gerhard Glatting
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, Ulm, Germany
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