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Copyright of Avances is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Background: hybrid studies produce a total radiation dose that is the result of the dose imparted by the radiopharmaceutical and that emitted by the computed tomography, therefore optimization is essential. Objective: to evaluate the relationship of the computed tomography dose with some image quality parameters in hybrid study protocols. Methods: to evaluate the image quality, the Catphan and Livermore phantom were used in 12 pre-established protocols of a Mediso single photon emission tomography equipment. The data for the dose descriptors for each study were obtained from the DICOM head. The classic image quality parameters such as noise and the MTF 50% for the Catphan phantom, and others such as the contrast-noise ratio, the average of Hounsfield numbers and their standard deviation in the regions of interest of the corresponding organs were compared, in Livermore's phantom. The relationship of these quality parameters with the dose descriptors of the different protocols was analyzed. Results: the quality-related parameters in the Catphan phantom did not show significant differences (p <0.05) between the different protocols for hybrid studies. Significant differences were found between the clinical protocols with different qualities and the standard clinical protocol, for the anthropomorphic phantom, in the standard deviation of the Hounsfield numbers and in the contrast-to-noise ratio (p <0.05). Conclusions: the study of the contrast noise ratio and the deviation of the computed tomography numbers in the regions of interest can serve as a quantitative parameter for the optimization of doses in the clinical setting.. [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]

This work summarizes the results of the national project Comprehensive quality improvement in the diagnosis and treatment of patients with cancer and other diseases, incorporating and strengthening radioguided surgery techniques. This project had the objective of raising the quality in the diagnosis and treatment of patients with cancer and other diseases, by introducing, expanding and optimizing the clinical use of radioguided surgery in Cuba. First, the technique was started in the “Hermanos Ameijeiras” hospitals, the National Institute of Oncology and Radiobiology and the Center for Medical Surgical Research, with the protocolized follow-up and the analysis of the clinical impact, the national guidelines were drawn up and the accreditation proceeded. of courses and workshops for the training of human resources, guaranteeing sustainability and extension to other hospitals. As main results, in February 2020, 570 breasts had been operated with this technique, with a rate between 65-70 % of unnecessary axillary emptyings avoided, noting the improvement in staging and diagnostic precision the decrease in surgical time per patient in 30 %, lower costs of surgery, fewer associated complications and shorter hospital stays due to minimally invasive surgery and a significant improvement in the quality of life of patients. Conclusions: radioguided surgery was introduced and consolidated as an oncological surgical optimization method. [ABSTRACT FROM AUTHOR]

Copyright of Revista Habanera de Ciencias Médicas is the property of Universidad de Ciencias Medicas de La Habana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Scattering is quite important for image activity quantification. In order to study the scattering factors and the efficacy of 3 multiple window energy scatter correction methods during 131I thyroid studies with a pinhole collimator (5 mm hole) a Monte Carlo simulation (MC) was developed. The GAMOS MC code was used to model the gamma camera and the thyroid source geometry. First, to validate the MC gamma camera pinhole-source model, sensibility in air and water of the simulated and measured thyroid phantom geometries were compared. Next, simulations to investigate scattering and the result of triple energy (TEW), Double energy (DW) and Reduced double (RDW) energy windows correction methods were performed for different thyroid sizes and depth thicknesses. The relative discrepancies to MC real event were evaluated. The accuracy of the GAMOS MC model was verified and validated. The image's scattering contribution was significant, between 27-40 %. The discrepancies between 3 multiple window energy correction method results were significant (between 9-86 %). The Reduce Double Window methods (15 %) provide discrepancies of 9-16 %. Conclusions: For the simulated thyroid geometry with pinhole, the RDW (15 %) was the most effective. [ABSTRACT FROM AUTHOR]

Breast cancer is the second most frequent neoplasm in the Cuban woman. Image techniques play a fundamental role for the diagnosis, staging and monitoring of the disease. This work had the objective of: Implement the Clinical Protocol for the scintimammography with 99mTc-MIBI for the detection of palpable tumor lesions in dense breasts, difficult mammographic assessment and suspected axillary metastatic lymph nodes employing a craft device of prone decubitus positioning. 35 patients were included with an average age of 51 years, who attended the central consultation of breast pathology at Dr. Salvador Allende Hospital. It was designed and constructed an artisanal device that made it possible to carry out the studies from an anatomical position pendant or pendulum of the breast, demonstrating its usefulness in the medical assessment of the scintimammography images. Of the studies carried out 17.1 % was positive for malignant mammary neoplastic tissue, with a specificity of 100 %. The number of unnecessary biopsies by false positive mammograms or inconclusive in lesions greater than 10 mm in diameter was decreased by 82.9 %. The clinical protocol was implemented for the scintimammography with 99mTc-MIBI for the detection of palpable tumor lesions in dense breasts, difficult mammographic assessment and suspected axillary metastatic lymph nodes employing a craft device of prone decubitus positioning. It proved to be a simple, reproducible and non-invasive test, which can facilitate and improve the diagnosis of breast cancer. [ABSTRACT FROM AUTHOR]

The paper focuses on a high-priority subject nationwide: the growing need for training in radiation protection for occupationally exposed workers and the strength of having specialized web portals on this matter. The Specialized Web Portal, EDUCPRA "Cuba's Portal for Education and Training in Radiological Protection", has been developed in this context, which makes available to its users, in an easy and integrated way, access to contents, regulations, national and international standards, directories, applications and services related to the matter that allow the identification, dissemination, and promotion of the training capacities in radiation protection. The main objective of EDUCPRA is to become the technological support of the National Strategy for Education and Training in Radiological Protection. EDUCPRA allows supervising the operation of the education and training activity in Radiological Protection in Cuba, and contributing to the processes of identification of needs, certification of personnel, and competence recognition of radiation protection courses. Through EDUCPRA, the available capacities to the country can be promoted to be able to comply with the training requirements established in the national regulatory framework, and the number of personnel trained by practice and occupational category can be known, allowing the evaluation of the effectiveness of the national training program. EDUCPRÁ will give visibility to the performance indicators of the training in Radiological protection in the country. [ABSTRACT FROM AUTHOR]