Patient-specific biokinetics and hybrid 2D/3D approach integration in OEDIPE software: Application to radioiodine therapy.

Background: The progression of targeted radionuclide therapy requires the development of dosimetry software accounting for patient-specific biokinetics. New functionalities were thus developed in the OEDIPE software, to deal with multiple 3D images or multiple planar images and a SPECT image.

Materiel & Method: Methods were implemented to recover patient biokinetics in volumes of interest.

A mobile high-resolution gamma camera for therapeutic dose control during radionuclide therapy.

Molecular radiotherapy is the most used treatment modality against malign and benign diseases of thyroid. In that context, the large heterogeneity of therapeutic doses in patients and the range of effects observed show that individualized dosimetry is essential for optimizing treatments according to the targeted clinical outcome.We developed a high-resolution mobile gamma camera specifically designed to improve the quantitative assessment of the distribution and biokinetics ofI at patients's bedside after treatment of thyroid diseases.

Using radial distribution functions to calculate cellular cross-absorbed dose foremitters: comparison with reference methods and application forF-FDG cell labeling.

To further improve the understanding ofbiological effects of incorporated radionuclides, it is essential to accurately determine cellular absorbed doses. In the case ofemitters, the cross-dose is a major contribution, and can involve up to millions of cells. Realistic and efficient computational models are needed for that purpose.

OpenDose: Open-Access Resource for Nuclear Medicine Dosimetry.

Radiopharmaceutical dosimetry depends on the localization in space and time of radioactive sources and requires the estimation of the amount of energy emitted by the sources deposited within targets. In particular, when computing resources are not accessible, this task can be performed using precomputed tables of specific absorbed fractions (SAFs) or S values based on dosimetric models. The aim of the OpenDose collaboration is to generate and make freely available a range of dosimetric data and tools.

Development of a dosimetric model for in vitro labelled cells with β emitters in PET tracking studies.

Positron emission tomography (PET) offers an effective method for tracking β emitters-labeled cells in vivo. However, in vitro high labelling activities used may cause cell damage or death. Our understanding of the impact of such procedure remains limited by the fact that the biological effects are usually linked to the activity per cell rather than the absorbed dose.

Optimisation of reconstruction, volumetry and dosimetry for Tc-SPECT and Y-PET images: Towards reliable dose-volume histograms for selective internal radiation therapy with Y-microspheres.

Purpose: In Selective Internal Radiation Therapy (SIRT), Tc-MAA SPECT images are commonly used to predict microspheres distribution but recent works used Y-microspheres PET images. Nevertheless, evaluation of the predictive power of Tc-MAA has been hampered by the lack of reliable comparisons between Tc-SPECT and Y-PET images. Our aim was to determine the "in situ" optimisation procedure in order to reliably compare Tc-SPECT and Y-PET images and achieve optimal personal dosimetry.

Application of rodes software to experimental biokinetic data for dose assessment in mice and rats.

H Miloudi, M Locatelli, G Autret, D Balvay, A Desbrée, E Blanchardon, J M Bertho: application of RODES software to experimental biokinetic data for dose assessment in mice and rats. In support of experimental studies of chronic, long-term contamination in rodents, voxel-based computer models were built representing adult mice and juvenile, adult and elderly rats of both sexes. RODES software was created to calculate absorbed radiation doses to organs with these specific anatomical models.

RODES software for dose assessment of rats and mice contaminated with radionuclides.

In order to support animal experiments of chronic radionuclides intake with realistic dosimetry, voxel-based three-dimensional computer models of mice and rats of both sexes and three ages were built from magnetic resonance imaging. Radiation transport of mono-energetic photons of 11 energies and electrons of 7 energies was simulated with MCNPX 2.6c to assess specific absorbed fractions (SAFs) of energy emitted from 13 source regions and absorbed in 28 target regions.

A mouse model of cytogenetic analysis to evaluate caesium137 radiation dose exposure and contamination level in lymphocytes.

In case of external overexposure to ionizing radiation, an estimation of its genotoxic effects on exposed individuals can be made retrospectively by the measurement of radiation-induced chromosome aberrations on circulating lymphocytes. Compared with external irradiation, intakes of radionuclides may, however, lead to specific features influencing dose distribution at the scale of body, of tissue or even of cell. Therefore, in case of internal contamination by radionuclides, experimental studies, particularly using animal models, are required to better understand mechanisms of their genotoxic effects and to better estimate the absorbed dose.

Dosimetry at the sub-cellular scale of Auger-electron emitter 99mTc in a mouse single thyroid follicle.

The Auger-electrons emitted by (99m)Tc have been recently associated with the induction of thyroid stunning in in vivo experiments in mice, making the dosimetry at the sub-cellular level of (99m)Tc a pertinent and pressing subject. The S-values for (99m)Tc were calculated using MCNP6, which was first validated for studies at the sub-cellular scale and for low energies electrons. The calculation was then performed for (99m)Tc within different cellular compartments in a single mouse thyroid follicle model, considering the radiative and non-radiative transitions of the (99m)Tc radiation spectrum.

Evaluation of Functionalized Polysaccharide Microparticles Dosimetry for SPECT Imaging Based on Biodistribution Data of Rats.

Purpose: Technetium-99 m (Tc-99 m)-labelled microparticles, functionalized with fucoidan to present a high affinity for P-Selectin, or [(99m)Tc] MP-fucoidan, were developed as a novel SPECT radiotracer for abdominal aortic aneurysm (AAA). As a prerequisite step forwards a clinical trial, the biodistribution and dosimetry of these [(99m)Tc] MP-fucoidan microparticles were performed in rats in order to estimate the absorbed and effective dose in humans.

Procedures: Microparticles with a maximum hydrodynamic diameter of 4 μm were obtained by crosslinking polysaccharides dextran and pullulan.

Liver Selective Internal Radiation Therapy with (90)Y resin microspheres: comparison between pre-treatment activity calculation methods.

Different methods to calculate (90)Y resin microspheres activity for Selective Internal Radiation Therapy (SIRT) were compared. Such comparison is not yet available and is needed in clinical practice to optimize patient specific treatment planning. 32 (99m)Tc-macroagregates (MAA) evaluations were performed, followed by 26 treatments.

Three dosimetry models of lipoma arborescens treated by 90Y synovectomy.

Purpose: Lipoma arborescens (LA) is a benign intra-articular lipomatous proliferation of the synovial membrane. This extremely rare condition has previously been treated by intra-articular (90)Y radiosynoviorthesis but dosimetry literature on this form of radionuclide therapy is nonexistent. The authors detail methodology for successful treatment of LA and provide for the first time estimates of radiation dosimetry.

Three-dimensional personalized Monte Carlo dosimetry in 90Y resin microspheres therapy of hepatic metastases: nontumoral liver and lungs radiation protection considerations and treatment planning optimization.

Unlabelled: In the last decades, selective internal radiation therapy (SIRT) has become a real alternative in the treatment of unresectable hepatic cancers. In practice, the activity prescription is limited by the irradiation of organs at risk (OAR), such as the lungs and nontumoral liver (NTL). Its clinical implementation is therefore highly dependent on dosimetry.

Comparison of organs' shapes with geometric and Zernike 3D moments.

The morphological similarity of organs is studied with feature vectors based on geometric and Zernike 3D moments. It is particularly investigated if outliers and average models can be identified. For this purpose, the relative proximity to the mean feature vector is defined, principal coordinate and clustering analyses are also performed.

Evaluation of absorbed and effective doses to patients from radiopharmaceuticals using the ICRP 110 reference computational phantoms and ICRP 103 formulation.

In diagnostic nuclear medicine, mean absorbed doses to patients' organs and effective doses are published for standard stylised anatomic models. To provide more realistic and detailed geometries of the human morphology, the International Commission on Radiological Protection (ICRP) has recently adopted male and female voxel phantoms to represent the reference adult. This work investigates the impact of the use of these new computational phantoms.

Two new δ-globin gene variants: Hb A(2)-Saint-Etienne [δ14(A11)Leu→Pro (HBD: c.44T>C)] and Hb A(2)-Marseille [δ22(B4) Ala→Lys (HBD: c.67G>A;68C>A)].

We report two new variants of the δ-globin gene: Hb A(2)-Saint-Etienne [δ14(A11)Leu→Pro] and Hb A(2)-Marseille [δ22(B4)Ala→Lys]. The first variant has a low rate of expression, the second results from a double nucleotide mutation on the same codon.

Construction of an extended library of adult male 3D models: rationale and results.

In order to best cover the possible extent of heights and weights of male adults the construction of 25 whole body 3D models has been undertaken. Such a library is thought to be useful to specify the uncertainties and relevance of dosimetry calculations carried out with models representing individuals of average body heights and weights. Representative 3D models of Caucasian body types are selected in a commercial database according to their height and weight, and 3D models of the skeleton and internal organs are designed using another commercial dataset.

Microdosimetry of alpha particles for simple and 3D voxelised geometries using MCNPX and Geant4 Monte Carlo codes.

Microdosimetry using Monte Carlo simulation is a suitable technique to describe the stochastic nature of energy deposition by alpha particle at cellular level. Because of its short range, the energy imparted by this particle to the targets is highly non-uniform. Thus, to achieve accurate dosimetric results, the modelling of the geometry should be as realistic as possible.

[EBV infection revealing a long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency in a 3-year-old boy].

Observation: We report on the case of a 3-year-old child from La Réunion island, who presented with hypoglycemic hypoketotic coma secondary to a primary Epstein-Barr virus (EBV) infection. The discovery of the G1528C homozygote mutation provided the diagnosis of long-chain-3-hydroxyacyl-CoA-dehydrogenase (LCHAD); an adapted dietary plan with prevention of fasting and L-carnitine supplementation was initiated. After 2 years, a pigmentary retinopathy appeared and muscle weakness increased.

Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons.

The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)).

Analytical and Monte Carlo assessment of activity and local dose after a wound contamination by activation products.

The activity and local dose following a right index finger wound contamination by activation products are assessed. Measurements with a high purity germanium detector and a four positions measurement protocol enabled a better localization of the contaminant source. From the source location and detector calibration, the remaining wound activity and local absorbed dose were deduced.