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The Center for Radiation Protection and Hygiene (CPHR) is the institution in Cuba that provides dosimetric calibration services of instruments at radiationl protection, radiotherapy, diagnostic radiology and interventionism level. This practice is developed by the Secondary Standard Dosimetric Laboratory and guarantees the metrological traceability of dose magnitudes to a Primary Standard Dosimetric Laboratory. It is carried out in compliance with a strict Radiation Protection Program designed to guarantee the radiation safety of people and the environment and to obtain the Operating License established in the national regulatory framework. The radiation protection program includes the necessary provisions to ensure the radiation protection of people while working with ionizing radiation sources. The safety of the personnel is one of the key elements of the program and is based on requirements such as radiological control both individually and of the workplaces, the design of the facilities, operational and safety procedures and inventory control, among other aspects that have allowed compliance with the annual dose constraints imposed by the Regulatory Authority for this category of exposed personnel. This paper presents the experiences in the application of these requirements for more than 20 years. [ABSTRACT FROM AUTHOR]

A summary of the fundamental lines of medical equipment for Cuban public health developed by the Center for Technological Applications and Nuclear Development (CEADEN) is made. These lines are grouped in two fundamental directions: optical instrumentation and nuclear instrumentation for medical diagnosis, quality control and dosimetry. The main developments and impacts achieved in these two directions in the National Health System are exposed, as well as their perspectives for present and future developments. [ABSTRACT FROM AUTHOR]

A basic element to achieve the measurement traceability is the correct implementation and dissemination of the measurement standards. In the case of dosimetry, there are internationally harmonized calibration methods; however difficulties may arise in their introduction related to the technical characteristics of the standards and the methods described in the technical documents. The use of commercially available dosimetry systems as secondary standards requires the personalized studies of their technical characteristics. The recommended methods do not always compatible with the available infrastructure and modifications are needed. The article makes a critical analysis of the implementation of the dosimetry secondary standards in the international arena based on the identified difficulties. [ABSTRACT FROM AUTHOR]

Given the lack of an internationally accepted code of practice for patient-specific quality control (PS-QA) of intensity-modulated radiation therapy (IMRT) treatments and the need to introduce this advanced modality into the clinical practice of the Radiation Therapy Service at the cedt-CIMEQ, the methodology recommended by the American Association of Physicists in Medicine Working Group 119 (AAPM TG-119) was assimilated and implemented. The procedures used for its habilitation and the results obtained are shown. It can be seen that the results obtained with the cedt-CIMEQ system for PS-QA, applied to all TG-119 test cases, fall within the confidence limits emanating from 10 reference centers. It could be concluded that, from the point of view of the reliability of the linear accelerator, the accuracy of the planning system and the precision of the PS-QA system, the cedt-CIMEQ is suitable for the introduction of IMRT in the clinic. [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.

Clinical Computed Tomography (CT) imaging is supported by a patient - technology - observers system. Such system involves dosimetric quantities associated with image quality descriptors, where operational factors are predictors. Knowledge of quantitative association between CT dosimetric and image quality quantities with systemic factors, provides the basis to devise scanner-specific optimization strategies. Kerma indexes were measured with a pencil ionization chamber free in air C a,100 and in phantom C pmma,x (x changes into c and p for center and periphery respectively). Polymethyl Methacrylate (PMMA) standard phantoms were used (diameters of 16 and 32 cm). Several operational factors of a Siemens Sensation 64 Cardiac were considered: estimated spectrums, tube potential F 8 (80 - 140 kV), tube current x time product F 1 (40 - 350 mAs) and total collimation at isocenter F 3 (2,7 - 19,2 mm). The water equivalent radius R w , an important factor for patient Size Specific Dose Estimators (SSDE), was estimated by taking into account the spectrums in each phantom. Average pixel noise was measured from Regions of Interest (ROIs) in water phantoms with radius of 2,5; 3; 6; 8 and 11,5 cm. A linear association was found between C pmma,p and C pmma,c . A dose reduction of C pmma,c = 2 mGy per tube rotation can be obtained from data analysis (head mode), with F 1 = 50 mAs, F 3 = 19,2 mm, resulting in average pixel noise of 20 Hounsfield Units (HU). Knowledge of noise association with C pmma,c provides a straightforward tool for quantitative optimization, considering a systemic approach, which includes patient - technology - observer factors.

Total Body Irradiation (TBI) is a radiotherapy technique that consists of irradiating homogeneously the whole patient’s body and it is characterized by an extended source to surface distances and the use of large irradiation fields. The limitations of the available input data and inherent problems with the calculation procedures make it very difficult to accurately determine the dose distributions in TBI. For these reasons, it is highly recommended to use In Vivo Dosimetry (IVD), to guarantee the quality of TBI treatments as a direct measurement of the delivered dose. An IVD QA system was implemented based on semiconductor diodes and radiochromic films. For the commissioning of the system, both detector types were calibrated independently, using as reference an ionization chamber with a valid certificate in terms of absorbed dose to water (Dw). This guarantees the traceability of the measurements. An experiment was carried out to simulate a clinical TBI procedure to a phantom. In this way, the calibration of the dosimetry system was confirmed.

From 1990 till 2011, a free health care program for children from areas affected by the Chernobyl accident was organized and implemented by the Cuban Government.. A significant number of qualified personal in medicine and science collaborated with this program. The information gathered for more than 21 years and the conclusive results obtained in the program are presented here. During this time, 26 114 patients, 84 % children, mostly from Ukraine, Russia and Belarus were treated in the mentioned program. Other aspects of the Cuban medical assistance in Ukraine and the main results obtained in the radiological impact evaluation of the accident on the children treated in Cuba are also included.

The Center for Radiation Protection and Hygiene was founded in 1985 to support the safe application of nuclear technologies in Cuba. Nowdays, the institution is considered as a national and regional reference for radiation protection , thanks to the comprehensive institutional strategy that support the solutions of the problems with priority in the country. The paper presents the overview about the main results of the center up today.

The Center for Radiation Protection and Hygiene was founded in 1985 to support the safe application of nuclear technologies in Cuba. Nowdays, the institution is considered as a national and regional reference for radiation protection, thanks to the comprehensive institutional strategy that support the solutions of the problems with priority in the country. The paper presents the overview about the main results of the center up today. [ABSTRACT FROM AUTHOR]

From 1990 till 2011, a free health care program for children from areas affected by the Chernobyl accident was organized and implemented by the Cuban Government. A significant number of qualified personal in medicine and science collaborated with this program. The information gathered for more than 21 years and the conclusive results obtained in the program are presented here. During this time, 26 114 patients, 84 % children, mostly from Ukraine, Russia and Belarus were treated in the mentioned program. Other aspects of the Cuban medical assistance in Ukraine and the main results obtained in the radiological impact evaluation of the accident on the children treated in Cuba are also included. [ABSTRACT FROM AUTHOR]

Optimization and verification of Specific Patient Treatment Planning with unsealed 131I sources in hyperthyroidism diseases is a desirable goal from medical and radiation protection viewpoints. In order to verify the estimation of patient’s specific treatment dose and his/her related parameters, a combination of 3 different apparatus or pieces of equipment used in nuclear medicine were studied - the Iodine Probe, a Philips Forte Camera with pinhole collimators and a Mediso Nucline with HEGP for planar and SPECT techniques- by using the typical neck phantom and 131I sources simulating diagnosis and treatment procedure. The linear behavior on diagnostic and therapeutic activity range was verified, showing a linear correlation fitting factor R2 > 0,99. The differences between thyroid uptake determinations in all equipment were less than 6 % for therapeutic activities and less than 1,1 % in the diagnostic range. The combined protocol to calculate all the necessary parameters for the patient treatment dose planning using 2D or 3D approach was established and verified, avoiding wasting time with gamma cameras and with only one administration of 131I.

This paper describes the development of an instrument for radiological monitoring, identified as Gamma Alarm (GAMAL01). The instrument monitors the increment of radiation count rate and produces an alarm signal, when the count rate becomes superior to a fixed threshold value. The threshold is fixed to assure that the signal emission will start when the value of the radiation count rate may cause a non acceptable radiological exposition of the personnel, according to the radiological safety regulations existing in the country. Following the signal the personnel must be evacuated from the affected place. The instrument consists of two sections, an analogical section and a digital one.

Total Body Irradiation (TBI) is a radiotherapy technique that consists of irradiating homogeneously the whole patient's body and it is characterized by an extended source to surface distances and the use of large irradiation fields. The limitations of the available input data and inherent problems with the calculation procedures make it very difficult to accurately determine the dose distributions in TBI. For these reasons, it is highly recommended to use In Vivo Dosimetry (IVD), to guarantee the quality of TBI treatments as a direct measurement of the delivered dose. An IVD QA system was implemented based on semiconductor diodes and radiochromic films. For the commissioning of the system, both detector types were calibrated independently, using as reference an ionization chamber with a valid certificate in terms of absorbed dose to water (Dw). This guarantees the traceability of the measurements. An experiment was carried out to simulate a clinical TBI procedure to a phantom. In this way, the calibration of the dosimetry system was confirmed. [ABSTRACT FROM AUTHOR]

Clinical Computed Tomography (CT) imaging is supported by a patient - technology - observers system. Such system involves dosimetric quantities associated with image quality descriptors, where operational factors are predictors. Knowledge of quantitative association between CT dosimetric and image quality quantities with systemic factors, provides the basis to devise scanner-specific optimization strategies. Kerma indexes were measured with a pencil ionization chamber free in air Ca,100 and in phantom Cpmma,x (x changes into c and p for center and periphery respectively). Polymethyl Methacrylate (PMMA) standard phantoms were used (diameters of 16 and 32 cm). Several operational factors of a Siemens Sensation 64 Cardiac were considered: estimated spectrums, tube potential F8 (80 - 140 kV), tube current x time product F1 (40 - 350 mAs) and total collimation at isocenter F3 (2,7 - 19,2 mm). The water equivalent radius Rw, an important factor for patient Size Specific Dose Estimators (SSDE), was estimated by taking into account the spectrums in each phantom. Average pixel noise was measured from Regions of Interest (ROIs) in water phantoms with radius of 2,5; 3; 6; 8 and 11,5 cm. A linear association was found between Cpmma,p and Cpmma,c. A dose reduction of Cpmma,c = 2 mGy per tube rotation can be obtained from data analysis (head mode), with F1 = 50 mAs, F3 = 19,2 mm, resulting in average pixel noise of 20 Hounsfield Units (HU). Knowledge of noise association with Cpmma,c provides a straightforward tool for quantitative optimization, considering a systemic approach, which includes patient - technology - observer factors. [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]

From 1990 till 2011, a free health care program for children from areas affected by the Chernobyl accident was organized and implemented by the Cuban Government. A significant number of qualified personal in medicine and science collaborated with this program. The information gathered for more than 21 years and the conclusive results obtained in the program are presented here. During this time, 26 114 patients, 84 % children, mostly from Ukraine, Russia and Belarus were treated in the mentioned program. Other aspects of the Cuban medical assistance in Ukraine and the main results obtained in the radiological impact evaluation of the accident on the children treated in Cuba are also included.

A patient-specific quality assurance (QA) program to carry out the dosimetric verification of the intensity modulated radiation therapy (IMRT) was optimized at the Department of Radiotherapy at the Institute of Oncology and Radiobiology, belonging to the Ministry of Public Health of Cuba. A dosimetric set-up composed of two-dimensional (2D) ionization chambers and an octagonal phantom were used to implement a patient-specific IMRT QA in a more comprehensive manner (collapsed and non-collapsed fields), keeping the accuracy and precision standards of these controls according to institutional protocols and international guidelines. The proposed procedure was used in three clinical IMRT cases for head and neck cancers. The confidence limit calculated from the passing rates for evaluated points in the compound dose maps was 90 % for the Gamma function comparison. The tolerance criteria used was a distance to agreement of 3 mm and the dose difference of 4 %. These results are within the institutional accepted limits and the recommended values as set by international guidelines for these kinds of tests.

This paper describes the development of an instrument for radiological monitoring, identified as Gamma Alarm (GAMAL01). The instrument monitors the increment of radiation count rate and produces an alarm signal, when the count rate becomes superior to a fixed threshold value. The threshold is fixed to assure that the signal emission will start when the value of the radiation count rate may cause a non acceptable radiological exposition of the personnel, according to the radiological safety regulations existing in the country. Following the signal the personnel must be evacuated from the affected place. The instrument consists of two sections, an analogical section and a digital one. [ABSTRACT FROM AUTHOR]

From 1990 till 2011, a free health care program for children from areas affected by the Chernobyl accident was organized and implemented by the Cuban Government. A significant number of qualified personal in medicine and science collaborated with this program. The information gathered for more than 21 years and the conclusive results obtained in the program are presented here. During this time, 26 114 patients, 84 % children, mostly from Ukraine, Russia and Belarus were treated in the mentioned program. Other aspects of the Cuban medical assistance in Ukraine and the main results obtained in the radiological impact evaluation of the accident on the children treated in Cuba are also included. [ABSTRACT FROM AUTHOR]

The evaluation of the solid state detectors response based on a Monte Carlo model of an Elekta Precise lineal accelerator, was done in this work for the beam energies of 6 y 15 MV. Simulations were performed using the EGSnrc code. Employing the optimal values of mean energy and FWHM from the primary electron beam, deposited dose in a voxelized water phantom at 100 cm of source to surface distance was calculated. Depth dose curves and lateral dose profi les were obtained. Comparison between simulations and the experimental values obtained for each detector, were done using acceptability criteria based on confi dence limits. Additionally outputs factors were analyzed in each one of the study cases. Good agreement between simulations and measurements were reached.

A patient-specific quality assurance (QA) program to carry out the dosimetric verification of the intensity modulated radiation therapy (IMRT) was optimized at the Department of Radiotherapy at the Institute of Oncology and Radiobiology, belonging to the Ministry of Public Health of Cuba. A dosimetric set-up composed of two-dimensional (2D) ionization chambers and an octagonal phantom were used to implement a patient-specific IMRT QA in a more comprehensive manner (collapsed and non-collapsed fields), keeping the accuracy and precision standards of these controls according to institutional protocols and international guidelines. The proposed procedure was used in three clinical IMRT cases for head and neck cancers. The confidence limit calculated from the passing rates for evaluated points in the compound dose maps was 90 % for the Gamma function comparison. The tolerance criteria used was a distance to agreement of 3 mm and the dose difference of 4 %. These results are within the institutional accepted limits and the recommended values as set by international guidelines for these kinds of tests. [ABSTRACT FROM AUTHOR]

The evaluation of the solid state detectors response based on a Monte Carlo model of an Elekta Precise lineal accelerator, was done in this work for the beam energies of 6 y 15 MV. Simulations were performed using the EGSnrc code. Employing the optimal values of mean energy and FWHM from the primary electron beam, deposited dose in a voxelized water phantom at 100 cm of source to surface distance was calculated. Depth dose curves and lateral dose profiles were obtained. Comparison between simulations and the experimental values obtained for each detector, were done using acceptability criteria based on confidence limits. Additionally outputs factors were analyzed in each one of the study cases. Good agreement between simulations and measurements were reached. [ABSTRACT FROM AUTHOR]

The Secondary Standard Dosimetry Laboratory of Cuba has implemented the calibration methodology of well-type chambers using the high dose rate 192Ir sources. The use of different source types, at the hospital site as a modification of the procedure using other source types in a permanent facility of the primary laboratory leads to the need to evaluate the performance of the secondary procedure for calibration. The present paper describes the proficiency test to Cuban laboratory by making a comparison of dosimetry standards used in Germany and Cuba. [ABSTRACT FROM AUTHOR]