A new approach for radiosynoviorthesis: A dose-optimized planning method based on Monte Carlo simulation and synovial measurement using 3D slicer and MRI

Abstract

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.

Synovitis and synovectomy in haemophilia

“…The RP should be a beta‐emitting radioisotope coupled with a carrier particle. RSO has been used over five decades for the treatment of refractory synovitis in patients with rheumatoid arthritis and other inflammatory conditions, such as haemophilic synovitis 27‐30,34‐37 . Yttrium‐90 ( 90 Y) in the forms of colloid citrate or silicate and rhenium ( 186 Re) sulphide are the preferred beta‐emitting radioisotopes in Europe, while chromic phosphorus ( 32 P) is currently the most used RP in North America 36 .…”

“…Like other nuclear medicine therapies, the success of RSO depends, among other factors, on the therapeutic dose effectively delivered to the target tissue, which in this case is the hypertrophic synovium 34,35,37 . While RPs applied to RSO are mostly absorbed by the synovium, and the remaining tissues receive negligible doses of radiation, the minimization of radiation exposure to non‐target structures is advised.…”

“…In this regard, regulatory agencies recommend the individualization of radiation doses to patients 34,36 . Tailoring doses for RSO, however, is a challenging task due to the difficulty in delineation of the synovial hypertrophic tissue 37 . Some groups perform ongoing studies regarding individualization of 90 Y dosing, applying Monte Carlo calculations and density specific anatomic models of the joints 37,38 .…”

“…Tailoring doses for RSO, however, is a challenging task due to the difficulty in delineation of the synovial hypertrophic tissue 37 . Some groups perform ongoing studies regarding individualization of 90 Y dosing, applying Monte Carlo calculations and density specific anatomic models of the joints 37,38 . The choice of RP, the administered activity, joint size and synovial thickness should be considered when calculating the proper injected activity, in order to achieve the ablation of the synovium without damaging non‐target tissues 37 …”

Internal Radiation Dose and Modeling Codes in Nuclear Medicine: A Fresh Look at Old Problems

“…The ideal situation would be to use the diagnostic image of the patient as anatomic model to estimate doses received by the diagnostic image itself or by a previous nuclear medicine treatment. Such "patient-specific" anatomic models can and are used in a research-level, where the Computed Tomography (CT) portion of Single Photon Emmission Tomography/Computed Tomography) SPECT/CT or Positron Emmission Tomography/Computed Tomography (PET/CT), or even Tridimensional Magnetic Resonance (3D MRI) as shown by Berdeguez et al [8] could be used for radiation transport simulation and new dose planning methodologies [8]. Problems of image-based patient-specific models include the lack of wholebody coverage in most cases and the need to segment those images to quantify organ absorbed doses separately.…”