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A new approach for radiosynoviorthesis: A dose‐optimized planning method based on Monte Carlo simulation and synovial measurement using 3D slicer and MRI
Author(s) -
Torres Berdeguez Mirta Bárbara,
Thomas Sylvia,
Rafful Patricia,
Arruda Sanchez Tiago,
Medeiros Oliveira Ramos Susie,
Souza Albernaz Marta,
Vasconcellos de Sá Lidia,
Lopes de Souza Sergio Augusto,
Mas Milian Felix,
Silva Ademir Xavier da
Publication year - 2017
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.12276
Subject(s) - monte carlo method , imaging phantom , radiation treatment planning , nuclear medicine , dosimetry , medicine , computer science , magnetic resonance imaging , electromagnetic coil , biomedical engineering , medical physics , radiology , physics , radiation therapy , mathematics , statistics , quantum mechanics
Purpose Recently, there has been a growing interest in a methodology for dose planning in radiosynoviorthesis to substitute fixed activity. Clinical practice based on fixed activity frequently does not embrace radiopharmaceutical dose optimization in patients. The aim of this paper is to propose and discuss a dose planning methodology considering the radiological findings of interest obtained by three‐dimensional magnetic resonance imaging combined with Monte Carlo simulation in radiosynoviorthesis treatment applied to hemophilic arthropathy. Method The parameters analyzed were: surface area of the synovial membrane (synovial size), synovial thickness and joint effusion obtained by 3D MRI of nine knees from nine patients on a SIEMENS AVANTO 1.5 T scanner using a knee coil. The 3D Slicer software performed both the semiautomatic segmentation and quantitation of these radiological findings. A Lucite phantom 3D MRI validated the quantitation methodology. The study used Monte Carlo N‐Particle eXtended code version 2.6 for calculating the S‐values required to set up the injected activity to deliver a 100 Gy absorbed dose at a determined synovial thickness. The radionuclides assessed were: 90Y, 32P, 188Re, 186Re, 153Sm, and 177Lu, and the present study shows their effective treatment ranges. Result The quantitation methodology was successfully tested, with an error below 5% for different materials. S‐values calculated could provide data on the activity to be injected into the joint, considering no extra‐articular leakage from joint cavity. Calculation of effective treatment range could assist with the therapeutic decision, with an optimized protocol for dose prescription in RSO. Conclusion Using 3D Slicer software, this study focused on segmentation and quantitation of radiological features such as joint effusion, synovial size, and thickness, all obtained by 3D MRI in patients’ knees with hemophilic arthropathy. The combination of synovial size and thickness with the parameters obtained by Monte Carlo simulation such as effective treatment range and S‐value, from which is calculated the injected activity, could be used for treatment planning in RSO. Data from this methodology could be a potential aid to clinical decision making by selecting the most suitable radionuclide; justifying the procedure, fractioning the dose, and the calculated injected activity for children and adolescents, considering both the synovial size and thickness.