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M Ginjaume

Publications and source records attributed to M Ginjaume.

At least 19 recordsLinked to original sources
PubMed2006

Overview of active personal dosemeters for individual monitoring in the European Union.

In 2001, the European Radiation Dosimetry Group, EURADOS, started a working group on 'Harmonisation of Individual Monitoring in Europe and the Dissemination of Information on New Techniques in this Field'. Within this group, one of the projects consisted of analysing the status of active personal dosemeters (APDs) in Europe. This paper reviews the regulatory requirements for APDs in 15 EU member states and summarises the main characteristics of commercial and new developments in this field. In particular, it focuses on the comparison of APD performance and standard passive dosimetry systems. Based on this information, an evaluation is initiated to establish why several countries are reluctant to accept APDs for dose records.

Environmental Exposure↗
PubMed2006

Comparison of two extremity dosemeters based on LiF:Mg,Cu,P thin detectors for mixed beta-gamma fields.

Two types of thin LiF:Mg,Cu,P detectors, GR-200F and MCP-Ns, have been characterised for use in the design of an extremity dosemeter for mixed beta-photon radiation fields. Both detectors consist of an extremely thin layer of sensitive material with effective thicknesses of 5 and 8 mg cm(-2), respectively, held in a 5 mg cm(-2) PVC ring holder. Dosimetric performance was analysed according to the ISO 12794 standard and compared with 240 mg cm(-2) TLD-100 measurements. In particular, the energy response was obtained for ISO narrow X-ray spectra, (137)Cs, (60)Co, (204)Tl and (90)Sr/(90)Y. From these measurements a mean calibration factor was calculated to estimate H(p)(0.07). Subsequently, the performance of the dosemeters was checked for a set of 10 different mixed photon and beta-photon fields. The study shows that the proposed dosemeters can estimate H(p)(0.07) in a wide range of mixed beta-photon fields with a maximum deviation from the given dose of 30% and an overall uncertainty of the order of 25% (k = 1). However, the results also highlight a large variability among the different thin detectors and, thus, the standard TLD-100 material is recommended whenever the workplace does not include low-energy beta radiation.

Beta Particles↗
PubMed2006

Dose evaluation in lung-equivalent media in high-energy photon external radiotherapy.

In high-energy photon external radiotherapy treatment planning systems (TPSs) are used to calculate the dose to the target volume and the dose distribution around it. Commonly used TPSs include algorithms based on measurements in water and often fail in the estimate of dose in the presence of heterogeneities. In this study TL detectors were used to study the reliability of the Cadplan (Varian) TPS in the presence of low-density heterogeneities such as the lung for 6 and 18 MV photon beams at different field sizes. TL measurements were compared with TPS calculations and Monte Carlo simulations performed with the PENELOPE MC code. In a phantom with lung heterogeneity, TL measurements and MC simulations agreed, with an average deviation inside the lung of 2%. In contrast, TPS results overestimated the dose inside the lung, with a maximum deviation of 39% for the 18 MV photon beam and a field size of 2 x 2 cm(2).

Algorithms↗
PubMed2006

Aspects of harmonisation of individual monitoring for external radiation in Europe: conclusions of a EURADOS action.

Following the publication of the EU Council Directive 96/29, EURADOS coordinated two working groups (WGs) for promoting the process of harmonisation on individual monitoring of occupationally exposed persons in Europe. An overview of the major findings of the second WG is presented. Information on the technical and quality standards and on the accreditation and approval procedures has been compiled. The catalogue of dosimetric services has been updated and extended. An overview of national regulations and standards for protection from radon and other natural sources in workplaces has been made, attempting to combine the results from individual monitoring for external, internal and workplace monitoring. A first status description of the active personal dosemeters, including legislative and technical information, and their implementation has been made. The importance of practical factors on the uncertainty in the dose measurement has been estimated. Even if a big progress has been made towards harmonisation, there is still work to be done.

Europe↗
PubMed2004

Photonuclear isotope characterization of a Siemens KDS 18 MV linac head.

Induced activity due to photonuclear reactions produced in the vacuum window of the accelerating wave-guide, the x-ray target and the beam-flattening filter of an 18 MV Siemens KDS linac has been studied. Measurements were performed using a high-purity portable germanium detector. Radioisotopes such as 196Au, 57Co, 60Co and other traces were detected one week after the last clinical use of the linac.

Cobalt Radioisotopes↗
PubMed2004

Active personal dosemeters for individual monitoring and other new developments.

In this paper, we will present a first (but not complete) status description of active personal dosemeters (APDs) and their implementation in European countries. In modern radiation protection practices, APDs are becoming absolutely necessary operational tools for satisfying the ALARA principle. Despite their success, they are relatively new for individual monitoring of workers. Regulation, legal requirements and calibration procedures are different in European member states. A catalogue of commercially available and prototype devices is presented. Improvement on devices and in implementation of calibration method are expected in the forthcoming years. End-user feedback experience and requirements are reported.

Body Burden↗
PubMed2004

Comparison of dose calculation algorithms in phantoms with lung equivalent heterogeneities under conditions of lateral electronic disequilibrium.

An extensive set of benchmark measurement of PDDs and beam profiles was performed in a heterogeneous layer phantom, including a lung equivalent heterogeneity, by means of several detectors and compared against the predicted dose values by different calculation algorithms in two treatment planning systems. PDDs were measured with TLDs, plane parallel and cylindrical ionization chambers and beam profiles with films. Additionally, Monte Carlo simulations by means of the PENELOPE code were performed. Four different field sizes (10 x 10, 5 x 5, 2 x 2, and 1 x 1 cm2) and two lung equivalent materials (CIRS, p(w)e=0.195 and St. Bartholomew Hospital, London, p(w)e=0.244-0.322) were studied. The performance of four correction-based algorithms and one based on convolution-superposition was analyzed. The correction-based algorithms were the Batho, the Modified Batho, and the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system and the TMS Pencil Beam from the Helax-TMS (Nucletron) treatment planning system. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. The only studied calculation methods that correlated successfully with the measured values with a 2% average inside all media were the Collapsed Cone and the Monte Carlo simulation. The biggest difference between the predicted and the delivered dose in the beam axis was found for the EqTAR algorithm inside the CIRS lung equivalent material in a 2 x 2 cm2 18 MV x-ray beam. In these conditions, average and maximum difference against the TLD measurements were 32% and 39%, respectively. In the water equivalent part of the phantom every algorithm correctly predicted the dose (within 2%) everywhere except very close to the interfaces where differences up to 24% were found for 2 x 2 cm2 18 MV photon beams. Consistent values were found between the reference detector (ionization chamber in water and TLD in lung) and Monte Carlo simulations, yielding minimal differences (0.4%+/-1.2%). The penumbra broadening effect in low density media was not predicted by any of the correction-based algorithms, and the only one that matched the experimental values and the Monte Carlo simulations within the estimated uncertainties was the Collapsed Cone Algorithm.

Algorithms↗
PubMed2002

Extremity and whole-body dosemeters for beta and beta gamma fields based on LiF:Mg,Cu,P thin detectors.

This study aims at proposing two TL dosemeters: one for the whole body and another for the extremities, for beta and gamma fields. Selected sensible material consists of 5 mg x cm(-2) LiF:Mg,Cu,P film (GR-200F) manufactured in China. Calibration was carried out according to ISO 4037-3, in terms of Hp(0.07), and dosimetric performance was analysed on the basis of IEC-1066 and ISO-12794 Standards. Experiments showed a satisfactory sensitivity of the proposed dosemeters for detecting beta radiation at protection levels and a very good energy response; thus, highly recommending their use for weakly penetrating radiation measurements. However, the homogeneity and the reproducibility of GR-200F are not found to be as reliable as in standard materials.

Arm↗
PubMed2001

The outlook for the application of electronic dosemeters as legal dosimetry.

This study analyses new trends of a set of 12 electronic personal dosemeters in order to gain an overview of their main advantages and limitations. Physical characteristics and radiological, mechanical and environmental performance were tested according to IEC-61526 Standard requirements. The study highlights the different behaviour of the selected dosemeters. In particular, it is demonstrated that three of the tested devices fulfilled most of the established requirements, whereas another three of them presented important faults. The parameters that need more development are, in general, the response at low energy photon and beta radiation, and the dose rate alarm features. In some cases, mechanical problems as well as interference in the response due to external electromagnetic fields were also found. However, the results of the study foresee a promising future for the application of the newest personal electronic dosemeters as legal personal dosemeters and show the need for internationally agreed technical requirements within the European countries.

Consumer Product Safety↗
PubMed2001

Implementing new recommendations for calibrating personal dosemeters.

This paper analyses the differences between the calibration procedures for personal dosemeters recommended by ICRU 47 and ISO 4037-3. The tissue equivalence of the PMMA and the ISO water slab phantoms are analysed by means of the Penelope Monte Carlo code for monoenergetic and filtered X ray photon beams and compared with the results of two other independent codes. The influence of the calibration method is also verified experimentally, both on a thermoluminescence and an electronic personal dosemeter. Good consistency between both calibration procedures is shown provided that a correction factor for backscatter differences between the PMMA and the ICRU phantom is introduced. The Monte Carlo simulation is used to determine this correction to a greater accuracy.

Calibration↗
PubMed1998

Thermoluminescence dosimetry applied to in vivo dose measurements for total body irradiation techniques.

BACKGROUND AND PURPOSE: In total body irradiation (TBI) treatments in vivo dosimetry is recommended because it makes it possible to ensure the accuracy and quality control of dose delivery. The aim of this work is to set up an in vivo thermoluminescence dosimetry (TLD) system to measure the dose distribution during the TBI technique used prior to bone marrow transplant. Some technical problems due to the presence of lung shielding blocks are discussed. MATERIALS AND METHODS: Irradiations were performed in the Hospital de la Santa Creu i Sant Pau by means of a Varian Clinac-1800 linear accelerator with 18 MV X-ray beams. Different TLD calibration experiments were set up to optimize in vivo dose assessment and to analyze the influence on dose measurement of shielding blocks. An algorithm to estimate midplane doses from entrance and exit doses is proposed and the estimated dose in critical organs is compared to internal dose measurements performed in an Alderson anthropomorphic phantom. RESULTS: The predictions of the dose algorithm, even in heterogeneous zones of the body such as the lungs, are in good agreement with the experimental results obtained with and without shielding blocks. The differences between measured and predicted values are in all cases lower than 2%. CONCLUSIONS: The TLD system described in this work has been proven to be appropriate for in vivo dosimetry in TBI irradiations. The described calibration experiments point out the difficulty of calibrating an in vivo dosimetry system when lung shielding blocks are used.

Algorithms↗
PubMed1998

Midplane dose determination during total body irradiation using in vivo dosimetry.

BACKGROUND AND PURPOSE: During TBI techniques an accurate determination of the dose distribution is very difficult when using commercial treatment planning systems. In order to determine the midplane dose, an algorithm was developed based on the use of in vivo dosimetry. MATERIALS AND METHODS: Scanditronix EDP-30 diodes were placed at the entrance and the exit surface for in vivo dosimetry. The proposed algorithm was validated firstly in a regular and homogeneous phantom of different thickness with an ionization chamber and TL dosimeters and secondly in an Alderson anthropomorphic phantom with TL dosimeters. In this study, in vivo measurements were evaluated in 60 patients and furthermore, in 20 of them, the midplane dose calculated with this algorithm was compared with the method described by Rizzotti A, Compri C, Garusi GF. Dose evaluation to patients irradiated by 60Co beams, by means of direct measurement on the incident and on the exit surfaces. Radiother. Oncol. 1985;3:279-283. RESULTS: No differences were found between the two methods. The differences between dose values calculated with both methods and dose values measured with the ionization chamber and TL dosimeters were within +/-22% and +/-4%, respectively, in the regular and homogeneous phantom and within +/-2% in the Alderson phantom. The algorithm was useful in calculating the midplane dose when heterogeneities as lungs were present. Even when partial transmission blocks were used to reduce the dose to the lungs, the algorithm with modified correction factors gave a midplane lung dose in the Alderson phantom within 1.3% of the measurements with TL dosimeters. For 360 patients' measurements in each A-P and P-A field, the relative deviations were analyzed between the measured and calculated entrance, exit dose and midplane dose and the prescribed dose, always applying the temperature correction factor. These deviations at the entrance dose were within +/-4%. Greater deviations were found for the exit dose measurements. Deviations larger than +/-10% corresponded in general to obese patients, with a thickness over 25 cm. The relative deviations between the total received and prescribed midplane doses in 60 patients were within +/-3%. CONCLUSIONS: The results indicate excellent correspondence between the total prescribed and calculated midplane doses using this algorithm while also no significant differences were found when the Rizzotti method was used. Comparison between doses measured with TL dosimeters in the core of Alderson phantom lungs and doses calculated from in vivo measurements showed that the proposed algorithm could be used in the presence of heterogeneities even when partial transmission blocks were used. The temperature correction factor must be applied in order to avoid a 2-3% dose overestimation.

Humans↗
PubMed1994

Estimation of peripheral dose from two linacs: Mevatron MX6700 and Mevatron KDS.

An empirical calculation method for high-energy beam peripheral dose estimation is described. The peripheral dose has been measured for a Siemens Mevatron MX6700 (6 MV) and a Siemens Mevatron KDS (6 and 18 MV) linear accelerators. The dose distribution is parameterized for each beam energy as a function of depth, distance from the edge of the field, and field size. A simple algorithm has been developed for dose calculation up to 100 cm from the field central axes. Predictions by this algorithm are compared with measurements in an Alderson phantom.

Particle Accelerators↗
PubMed1989

Gastric emptying in marathon runners.

Radionuclide gastric emptying studies using 99m-Tc human serum albumin egg omelette have been carried out in 10 long distance runners at rest and during a 90 minute run at sustained speed. Resting values are compared with controls comprising 10 sedentary subjects. Runners show a significantly accelerated basal gastric emptying (runners t 1/2 = 67.7 (5.9) min; sedentaries t 1/2 = 85.3 (4.5) min, p less than 0.001). The exercise had no significant effect on gastric emptying in these trained subjects (exercise t 1/2 = 66.8 (5.9) min, p = NS), suggesting adaptation to exercise.

Adaptation, Physiological↗
PubMed1988

Indium-111 antimyosin scintigraphy to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

Indium-111 antimyosin scans were used to assess myocardial damage in patients with suspected myocarditis and cardiac transplant rejection. The calculation of a myocardium to lung ratio (AM index) to quantify antimyosin uptake was performed. AM index in normal subjects (n = 8) at 48 hr postinjection was 1.46 +/- 0.04. In patients with suspected myocarditis (16 studies in 13 patients), AM index was 2.0 +/- 0.5 (p less than 0.001); suggesting a considerable incidence of ongoing cell damage in this group, despite the small proportion of positive right ventricular endomyocardial biopsy (RVbx) (4/13). In patients studied after cardiac transplantation (37 studies in 17 patients), AM indexes correlated with RVbx. In patients with RVbx proven rejection (n = 14), AM index was 1.87 +/- 0.19 (p less than 0.001). In patients with RVbx showing infiltrates but not myocyte damage (n = 13), AM index was 1.80 +/- 0.27 (p = 0.02). In patients with normal RVbx (n = 10), AM index was 1.56 +/- 0.17 (p = NS versus controls; p = 0.001 versus those with positive RVbx). Calculated AM indexes correlated with graded visual analysis of the scans (r = 0.823; p = 0.001). Antimyosin scans are an appropriate method to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

Adult↗