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Hyperthyroidism is one of the most frequent MN treatments; however, quantification of 131I activity in thyroid using Single Photon Computer Tomography (SPECT) and combined with Computer Tomography (SPECT/CT techniques has almost no bibliographic history. This work studied the impact on 131I activity accuracy quantification of scatter corrections using CT information. Three sources of known activity were used for the calibration process (1.06 MBq 2.61 MBq and 4.66 MBq) with a typical uncertainty of 2.4 % and the classic thyroid phantom. The calibration factors and their uncertainty were calculated for each case. To analyze the accuracy of the system, a set of 11 sources (with activities between 1.37 MBq-3.92 MBq) were calculated and the uncertainty was estimated in each case. The relative discrepancies of the calculated activity versus reference were compared (p<0.05). The lowest average discrepancy resulted was 3 % (from 5 to 7 %) corresponding with any correction using CT. The uncertainties were found in the range of 9 to 11 %, being consistent with the discrepancies already found. Conclusions: The corrections of attenuation and dispersion by MC using CT information did not improve the 131I activity quantification accuracy in the geometry of classical thyroid phantom; although it is recommended to expand the range of masses of the thyroid to better represent the wide specific patient clinical situation and confirm these results. [ABSTRACT FROM AUTHOR]

The diagnostic image must be carried out with the minimum necessary exposure of the patient that allows the objective of the diagnosis to be satisfactorily achieved. For this reason, diagnostic reference levels emerge and are established as dynamic tools to help optimize radiation protection, contribute to the standardization of practices and strengthen culture of safety, without compromising the clinical purpose of each examination or process. The objective of this work is to provide an updated overview of the establishment and use of these levels for nuclear medicine and hybrid imaging. It is identified that to establish and use them properly, trained personnel and coordination and collaboration activities are required among multiple actors, including medical services, health authorities, professional organizations and regulatory bodies. The accelerated development of technology generally exceeds the change in regulations, so these levels must be updated periodically, in order to fulfil their role as a guide and spur for optimization. The worldwide expansion of hybrid technologies and their growing use are a phenomenon of the last decade, so the establishment of these levels for such technologies has not been consolidated, although countries such as the United Kingdom and Australia show solid steps in this address. Research has been carried out with phantoms and directly with patients, the latter with a more useful contribution of information. The installation of hybrid equipment in Cuba demands this study, hence its importance. [ABSTRACT FROM AUTHOR]

The introduction in Cuba of imaging hybrid systems in nuclear medicine has become a challenge for medical physicist in order to guaranty the patient´s radiation safety and proper dose estimation. The aim of this study was to retrospectively evaluate the CT radiation doses for studies performed with a SPECT/CT hybrid system (SPECT/CT). A MATLAB “in house” made tool was tested and validated for this purpose. 62 patients with CT studies were manually and automatically reviewed; the tool could visualize and properly recover the patient personal information, CT protocol and dose related data from the DICOM header in the SPECT/CT study file. The CT volume dose index (CTDIvol) parameter was used for calculating the CT dose-length product (DPL) and the effective doses (E). The CT radiation dose preliminary results were on the range of those reported by others authors for the typical studies, demonstrating the efficacy of the tool developed and the CT dose assessment method. [ABSTRACT FROM AUTHOR]

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The main contributions in the applications of nuclear sciences and technologies to the diagnosis and treatment of neoplasic diseases, obtained by medical physicists from various Havana institutions are summarized. Additionally, the main activities to guarantee the training and accreditation of medical physicists for radiodiagnosis, nuclear medicine, radiotherapy and radiation protection services in Havana hospital network is presented. [ABSTRACT FROM AUTHOR]

In 2013, the European Association of Nuclear Medicine Dosimetry Committee recommends a "Standard Operational Procedures for Hyperthyroidism Pre-Therapeutic Dosimetry" based on the assessment of the individual 131I uptake and kinetics. To estimate the 3D dose delivery deviations from prescribed dose during patient specific application of this SOP, a computer Matlab application was developed and verified. It was design to execute: radiopharmaceutical curve fitting, cumulated activity calculations, functional thyroid mass estimation, obtain the therapeutic planning activity to warranty the prescribed dose and produce the 3D planning dose map and related dosimetry parameters. 6 patients with 150-400Gy prescribed dose data planning (average 241,67Gy) were analysed using the developed application. The developed system was verify successfully using a test image phantom and 6 known pharmacokinetics data. The tridimensional thyroid volume cumulated activity and dose distributions were heterogeneous. 3D dose distribution showed standard deviations between 18.01- 27.08 % of prescribed dose. The differences between maximum and minimum dose value per voxel/ MBq were 74-129%. According to the result, between 50,2 % and 71,4 % of patient's thyroid will be treat with a dose of DP±20 % of planned dose, the rest will be overdose or sub dose. Conclusions: the 3D treatment planning dose distribution were completely no-homogenous, the significant difference observed should be study in the future more deeply in order to optimized the hyperthyroidism iodine treatment. [ABSTRACT FROM AUTHOR]