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Measurements of pediatric radiation exposure during barium imaging procedures
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Abstracts / Physica Medica 32 (2016) 284–339
Purpose. The aim of this work is to measure the structural complexity of brain neurons’ using 2 dimensional tractography DTI images and compare the complexity of the textures originating from healthy brain neurons. Materials and methods. Two-dimensional diffusion tensor images from a group of healthy subjects were studied. The generated neuronal tracts by various ROIs on the DTI maps were processed using the Box Counting method and measure self-similarity. The Hausdorff fractal dimension Df was then calculated. Lacunarity studies were also performed in order to describe the complex interconnectivity of neurons. Results. Average fractal dimensions were calculated based on the current resolution of the 2D images for different observational angles. High lacunarity derived values indicate the interconnection in the neurons’ distribution as well as clustering and connectivity of the neuron imaged ensemble. Conclusion. The results of this study demonstrate firstly that, the average estimated fractal dimension of tractography images for healthy subjects is Df = 1.60 and secondly statistical self-similarity features. http://dx.doi.org/10.1016/j.ejmp.2016.07.246
MEASUREMENTS OF PEDIATRIC RADIATION EXPOSURE DURING BARIUM IMAGING PROCEDURES A. Sulieman a,*, B. Elhag b, K. Alzimami c, C. Kappas d, K. Theodorou d a Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, P.O. Box 422, Alkharj 11943, Saudi Arabia b Radiology and Medical Imaging Department, Alghad International Colleges for Applied Medical Sciences, Almadinah Almunawra, Saudi Arabia d King Abdulaziz University, School of Medicine, Radiology Department, Saudi Arabia c Radiological Sciences Department, College of Applied Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia d Medical Physics Department, University Hospital of Larissa, PO Box 1425, Larissa 41110, Greece ⇑ Corresponding author.
Radiological imaging has been considered a vital tool in the diagnosis of gastrointestinal tract (GIT) disorders. Gastrointestinal radiography (GIR) has been a major and first-choice method for diagnosing GIT diseases with barium as contrast media since its emergence in 1910. Radiographic examination of children, especially neonates, attracts particular interest because of the increased opportunity for expression of delayed radiogenic cancers as a consequence of relative longer life expectancy. Barium studies are of particular interest because it constitutes 5% of the total number of radiological examinations and 17% of the collective doses. Although, the task is important, there are few data on radiation doses to infants and children undergoing barium procedures. The current study intends to evaluate the radiation dose to pediatric patients during barium studies and to estimate the effective doses and radiation risk of the aforementioned procedures. A total of 43 pediatric barium procedures were performed in this study. 21.7% of the sample was barium meal, 8.6% were undergone barium swallow while 69.5% of the sample were barium enemas. Entrance surface air kerma (ESAKs) were calculated from patient exposure parameters using DosCal software. Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB).
The mean film numbers was 12.4, 8.9 and 8 for barium meal, barium enema and barium swallow, respectively. The maximum number of X rays was obtained in barium meal (21 film per a single procedure). The mean patient doses per procedure were 2.1 ± 0.8 mGy, 3.0 ± 23 mGy and 1.2 ± 0.2 mGy for barium meal, swallow and enema, respectively. The mean effective doses were 0.3 mSv, 1.0 mSv and 0.2 mSv at the same order. The dose values in this study were higher than previous studies. The unnecessary radiation exposure can be reduced significantly by reducing the number of films and screening time. Diagnostic reference level is recommended to improve the practice. Disclosure. Authors have nothing to disclose. http://dx.doi.org/10.1016/j.ejmp.2016.07.247
DAILY CLINAC QA RESULTS WITH ARCCHECK IN ELEKTA SYNERGY Fernando Tato de las Cuevas *, Pablo Domingo Fernandez Medical Physics Department, Hospital Universitario de Canarias, Tenerife, Spain ⇑ Corresponding author. Introduction. ArcCheck (Sun Nuclear, FL) is a 4D detector phantom designed to check helical treatments in radiotherapy. The phantom software and detectors data accessibility makes possible to use this phantom in LINAC QA (lineal accelerator quality assurance). Purpose. Develop a daily LINAC QA program using ArcCheck phantom that checks dosimetry parameters and evaluate the results after 5 months. Materials and methods. The LINAC is an Elekta Synergy. The QA steps are: Full arc warning up beam (FAW). Warms up the ionization chamber placed inside the phantom with a beam that covers the whole phantom (20 cm inplane, 2.5 cm crossplane). Make a gamma analysis with 20% threshold comparing the measured with the reference state. Static beam. Irradiate a 10 10 cm static field and import the detectors dose from an Excel Workbook that evaluates beam shape, beam quality factor, dose output and diodes signal degradation. Irradiate a VMAT treatment. Make a gamma analysis comparing the measured with the reference data in order to check monitor unit system, gantry speed and MLC reproducibility Results. FAW: The result in SNC patient must be a uniform dose distribution in the detector matrix. It has detected misalignments in sagittal laser direction as low as 0.3°. Static beam: All measured parameters are in tolerance. VMAT treatment: The gamma analysis has a coincidence of more than 95% every day. These results are in agreement with other QA test. All QA take less than 8 min. Conclusion. The daily QA developed is fast, complete and effective. Disclosure. None. http://dx.doi.org/10.1016/j.ejmp.2016.07.248
Abstracts / Physica Medica 32 (2016) 284–339
Purpose. The aim of this work is to measure the structural complexity of brain neurons’ using 2 dimensional tractography DTI images and compare the complexity of the textures originating from healthy brain neurons. Materials and methods. Two-dimensional diffusion tensor images from a group of healthy subjects were studied. The generated neuronal tracts by various ROIs on the DTI maps were processed using the Box Counting method and measure self-similarity. The Hausdorff fractal dimension Df was then calculated. Lacunarity studies were also performed in order to describe the complex interconnectivity of neurons. Results. Average fractal dimensions were calculated based on the current resolution of the 2D images for different observational angles. High lacunarity derived values indicate the interconnection in the neurons’ distribution as well as clustering and connectivity of the neuron imaged ensemble. Conclusion. The results of this study demonstrate firstly that, the average estimated fractal dimension of tractography images for healthy subjects is Df = 1.60 and secondly statistical self-similarity features. http://dx.doi.org/10.1016/j.ejmp.2016.07.246
MEASUREMENTS OF PEDIATRIC RADIATION EXPOSURE DURING BARIUM IMAGING PROCEDURES A. Sulieman a,*, B. Elhag b, K. Alzimami c, C. Kappas d, K. Theodorou d a Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, P.O. Box 422, Alkharj 11943, Saudi Arabia b Radiology and Medical Imaging Department, Alghad International Colleges for Applied Medical Sciences, Almadinah Almunawra, Saudi Arabia d King Abdulaziz University, School of Medicine, Radiology Department, Saudi Arabia c Radiological Sciences Department, College of Applied Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia d Medical Physics Department, University Hospital of Larissa, PO Box 1425, Larissa 41110, Greece ⇑ Corresponding author.
Radiological imaging has been considered a vital tool in the diagnosis of gastrointestinal tract (GIT) disorders. Gastrointestinal radiography (GIR) has been a major and first-choice method for diagnosing GIT diseases with barium as contrast media since its emergence in 1910. Radiographic examination of children, especially neonates, attracts particular interest because of the increased opportunity for expression of delayed radiogenic cancers as a consequence of relative longer life expectancy. Barium studies are of particular interest because it constitutes 5% of the total number of radiological examinations and 17% of the collective doses. Although, the task is important, there are few data on radiation doses to infants and children undergoing barium procedures. The current study intends to evaluate the radiation dose to pediatric patients during barium studies and to estimate the effective doses and radiation risk of the aforementioned procedures. A total of 43 pediatric barium procedures were performed in this study. 21.7% of the sample was barium meal, 8.6% were undergone barium swallow while 69.5% of the sample were barium enemas. Entrance surface air kerma (ESAKs) were calculated from patient exposure parameters using DosCal software. Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB).
The mean film numbers was 12.4, 8.9 and 8 for barium meal, barium enema and barium swallow, respectively. The maximum number of X rays was obtained in barium meal (21 film per a single procedure). The mean patient doses per procedure were 2.1 ± 0.8 mGy, 3.0 ± 23 mGy and 1.2 ± 0.2 mGy for barium meal, swallow and enema, respectively. The mean effective doses were 0.3 mSv, 1.0 mSv and 0.2 mSv at the same order. The dose values in this study were higher than previous studies. The unnecessary radiation exposure can be reduced significantly by reducing the number of films and screening time. Diagnostic reference level is recommended to improve the practice. Disclosure. Authors have nothing to disclose. http://dx.doi.org/10.1016/j.ejmp.2016.07.247
DAILY CLINAC QA RESULTS WITH ARCCHECK IN ELEKTA SYNERGY Fernando Tato de las Cuevas *, Pablo Domingo Fernandez Medical Physics Department, Hospital Universitario de Canarias, Tenerife, Spain ⇑ Corresponding author. Introduction. ArcCheck (Sun Nuclear, FL) is a 4D detector phantom designed to check helical treatments in radiotherapy. The phantom software and detectors data accessibility makes possible to use this phantom in LINAC QA (lineal accelerator quality assurance). Purpose. Develop a daily LINAC QA program using ArcCheck phantom that checks dosimetry parameters and evaluate the results after 5 months. Materials and methods. The LINAC is an Elekta Synergy. The QA steps are: Full arc warning up beam (FAW). Warms up the ionization chamber placed inside the phantom with a beam that covers the whole phantom (20 cm inplane, 2.5 cm crossplane). Make a gamma analysis with 20% threshold comparing the measured with the reference state. Static beam. Irradiate a 10 10 cm static field and import the detectors dose from an Excel Workbook that evaluates beam shape, beam quality factor, dose output and diodes signal degradation. Irradiate a VMAT treatment. Make a gamma analysis comparing the measured with the reference data in order to check monitor unit system, gantry speed and MLC reproducibility Results. FAW: The result in SNC patient must be a uniform dose distribution in the detector matrix. It has detected misalignments in sagittal laser direction as low as 0.3°. Static beam: All measured parameters are in tolerance. VMAT treatment: The gamma analysis has a coincidence of more than 95% every day. These results are in agreement with other QA test. All QA take less than 8 min. Conclusion. The daily QA developed is fast, complete and effective. Disclosure. None. http://dx.doi.org/10.1016/j.ejmp.2016.07.248