The Evaluation of Conventional X-ray Exposure Parameters Including Tube Voltage and Exposure Time in Private and Governmental Hospitals of Lorestan Province, Iran
01 Jun 2015-Iranian Journal of Medical Physics (Mashhad University of Medical Sciences)-Vol. 12, Iss: 2, pp 85-92
TL;DR: The results of this study showed that old X-ray equipments with poor or no maintenance are probably the main sources of reducing radiographic image quality and increasing patient radiation dose.
Abstract: Introduction In radiography, dose and image quality are dependent on radiographic parameters. The problem is caused from incorrect use of radiography equipment and from the radiation exposure to patients much more than required. Therefore, the aim of this study was to implement a quality-control program to detect changes in exposure parameters, which may affect diagnosis or patient radiation dose. Materials and Methods This cross-sectional study was performed on seven stationary X-ray units in sixhospitals of Lorestan province. The measurements were performed, using a factory-calibrated Barracuda dosimeter (model: SE-43137). Results According to the results, the highest output was obtained in A Hospital (M1 device), ranging from 107×10-3 to 147×10-3 mGy/mAs. The evaluation of tube voltage accuracy showed a deviation from the standard value, which ranged between 0.81% (M1 device) and 17.94% (M2 device) at A Hospital. The deviation ranges at other hospitals were as follows: 0.30-27.52% in B Hospital (the highest in this study), 8.11-20.34% in C Hospital, 1.68-2.58% in D Hospital, 0.90-2.42% in E Hospital and 0.10-1.63% in F Hospital. The evaluation of exposure time accuracy showed that E, C, D and A (M2 device) hospitals complied with the requirements (allowing a deviation of ±5%), whereas A (M1 device), F and B hospitals exceeded the permitted limit. Conclusion The results of this study showed that old X-ray equipments with poor or no maintenance are probably the main sources of reducing radiographic image quality and increasing patient radiation dose.
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TL;DR: In this article, the authors conducted a systematic review of published articles to survey radiation protection in diagnostic x-ray imaging in Iran, which revealed undesirable level of radiation protection regarding the use of shielding tools for patients, radiation collimation, use of film bag in dental radiography and quality control programs.
Abstract: Background and purpose: Increasing number of patients undergoing x-ray examinations has created a global concern due to the deleterious biological effects associated with x-ray exposure. Adherence to ionizing radiation protection principles could be of great benefit in decreasing these effects. Accordingly, the aim of this study was to survey radiation protection in diagnostic x-ray imaging in Iran using systematic review of published articles. Materials and methods: Without any time limitation, some databases including SID, Magiran, IranMedex, Irandoc, Google-Scholar, Medlin, Embase and PubMed were searched. A total of 122 articles was obtained during the primary research. After elimination of duplicate and irrelevant articles, 39 articles (published in 1997 to 2015) were selected for final review. Results: The researches were performed in conventional radiology centers (n=24), dental radiography (n= 8), nuclear medicine (n=2), mammography (n= 1), computed tomography (n=1), dental radiography and radiology (n= 1), and total diagnostic X-ray departments (n= 2). Totally, 874 diagnostic centers and 1677 radiographers were studied. These studies revealed undesirable level of radiation protection regarding the use of shielding tools for patients, radiation collimation, use of film bag in dental radiography, and quality control programs. But, environmental radiation doses and the use of film bag in radiology centers were found to be in appropriate level. Conclusion: Despite increasing application of x-ray in medical diagnosis, radiation protection did not considerably change in Iran. So a national strategic program on radiation protection seems to be necessary. Such programs must be developed by ministry of health and radiation protection affairs of national atomic energy organization and its administration must be monitored permanently.
19 citations
TL;DR: There were wide variations in QC test results, perhaps mainly due to the fact that it is not an obligation to implement QC programs in Iran, and the most important problems were non-reciprocity of exposure, nonlinearity of Exposure with milliampere-second (mAs), kVp and timer inaccuracy.
Abstract: Introduction Quality control (QC) techniques are used in monitoring and maintenance of the components of an x-ray system. QC of radiology devices plays a significant role in reduction of medication dose and optimization of image quality. This study aimed to conduct QC tests on randomly selected radiology devices, installed in diagnostic imaging departments of Iran. Materials and Methods In total, quality control tests were conducted on 51 conventional radiology devices installed in 20 cities of Iran in order to assess the accuracy of peak kilovoltage (kVp), exposure time, exposure linearity and reciprocity, reproducibility of exposure and determination of half-value layer (HVL) using a calibrated Mult-O-Meter. Results In this study, 38.6% of devices had intolerable variance of kVp accuracy. The results of 34.5% of devices were out of the acceptable limits in exposure time accuracy test. In 46.7% and 53.1% of devices, variance was greater than the acceptable range for exposure linearity and exposure reciprocity, respectively. In terms of reproducibility of exposure test, the reproducibility variance and percentage of tube output variations in 19.4% of devices exceeded the limits. Moreover, the thickness of first HVL was lower than the acceptable limit in 14.7% of devices. Conclusion According to the results of this study, there were wide variations in QC test results, perhaps mainly due to the fact that it is not an obligation to implement QC programs in Iran. The most important problems were non-reciprocity of exposure, nonlinearity of exposure with milliampere-second (mAs), kVp and timer inaccuracy. Involvement of medical physicists, radiologists and radiographers in the implementation of QC programs at various stages of development, installation and use of equipment should enable the gradual improvement in equipment performance.
12 citations
Cites background from "The Evaluation of Conventional X-ra..."
...Many studies have been performed on the QC of diagnostic radiographic equipment in Chaharmahal and Bakhtiari, Zanjan, Khorasan, Lorestan, Golestan, Khuzestan, Hormozgan and Kerman provinces of Iran [19-27]....
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...(2015) evaluated the performance of radiographic X-ray equipment in Khuzestan and Lorestan provinces, respectively [22, 24]....
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...Moreover, Rasuli et al. (2014) and Gholami et al. (2015) evaluated the performance of radiographic X-ray equipment in Khuzestan and Lorestan provinces, respectively [22, 24]....
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TL;DR: As radiographic X-ray equipments in Kerman province are relatively old with a high workload, it is recommended that AEOI modify the current policies by changing the frequency of QC test implementation to at least once a year.
Abstract: Introduction Application of quality control (QC) programs at diagnostic radiology departments is of great significance for optimization of image quality and reduction of patient dose. The main objective of this study was to perform QC tests on stationary radiographic X-ray machines, installed in 14 hospitals of Kerman province, Iran. Materials and Methods In this cross-sectional study, QC tests were performed on 28 conventional radiographic X-ray units in Kerman governmental hospitals, based on the protocols and criteria recommended by the Atomic Energy Organization of Iran (AEOI), using a calibrated Gammex QC kit. Each section of the QC kit incorporated different models. Results Based on the findings, kVp accuracy, kVp reproducibility, timer accuracy, timer reproducibility, exposure reproducibility, mA/timer linearity, and half-value layer were not within the acceptable limits in 25%, 4%, 29%, 18%, 11%, 12%, and 7% of the evaluated units (n=28), respectively. Conclusion As radiographic X-ray equipments in Kerman province are relatively old with a high workload, it is recommended that AEOI modify the current policies by changing the frequency of QC test implementation to at least once a year.
10 citations
Cites background from "The Evaluation of Conventional X-ra..."
...Materials and Methods In this cross-sectional study, QC tests were performed on 28 conventional radiographic X-ray units in Kerman governmental hospitals, based on the protocols and criteria recommended by the Atomic Energy Organization of Iran (AEOI), using a calibrated Gammex QC kit....
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...Some studies have revealed that QC parameters of radiographic equipments are unacceptable, based on QC regulations of diagnostic radiology, suggested by the Atomic Energy Organization of Iran (AEOI) [9-14]....
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...Conclusion As radiographic X-ray equipments in Kerman province are relatively old with a high workload, it is recommended that AEOI modify the current policies by changing the frequency of QC test implementation to at least once a year....
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...Specification of some conventional X-ray unit parameters, which were adopted in our study based on the basic criteria by AEOI, is presented in Table 1 [16]....
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...Therefore, as radiographic X-ray equipments in Kerman province are relatively old with a high workload, it is recommended that AEOI modify the current policies by changing the frequency of QC test implementation to at least once a year....
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TL;DR: Improving quality control standards may improve diagnostic quality, reduce the number of repeated tests, and reduce patient exposure in diagnostic imaging.
Abstract: One of the most important steps in the optimization process in diagnostic imaging is the quality control (QC) of digital radiology devices. The defects of irradiation diagnostic devices in the framework of QC programs were assessed in imaging centers of Tehran province. To perform this schedule, various parameters such as kVp, milli-Ampere (mA), irradiation time, HVL, and additional filters were evaluated by three qualitative control tests. By using Pehamed phantom, Piranha dosimeter, and response time index, the QC of three radiological devices from three different companies—Samsung, Spellman, and Philips—was measured for the first time in Iran. The data obtained through the imagej software were analyzed. Different parameters including dynamic range, contrast, spatial resolution, beam quality, and homogeneity were compared from three devices. The HVL for Al was measured at 2.85 mm over the beam quality. Increasing the voltage increased the HVL so that the constant coefficients for PMX-III and a new electronic multimeter were 0.0787 and 0.0786, correspondingly. Also by raising dose, the irradiation index increased for different kVp and Al-HVL. The pixel values in different ROIs were assessed as there was no discrepancy at the center, but the greatest difference was emerged by 5.329 on the left. Of the pair of lead lines available in the phantom with size of 0.5–5 lp/mm at 45$$^\circ $$, 2.8 line pairs were completely separate to determine the resolution. Also, of the 16 copper sheets with thicknesses from 0 to 3.5, all sheets with thicknesses of 0.36 to 3.48 mm were visible. The coefficient of variation (CV) and the noise fluctuations were calculated for the adjusted voltage, irradiation time, and the output dose. At 100 mA, the maximum CV of the output dose was 0.0074 for 90 kVp-80 ms. The outcomes demonstrated that the Philips digital imaging system is of fairly good quality in all QC tests. Comparatively, the patient absorbed dose with the Spellman X-ray machine was less than with the other two devices. By recorded doses in assessment of linearity detector response, the Samsung and Philips machines demonstrated a great regression coefficient of 99% at different exposures. Improving quality control standards may improve diagnostic quality, reduce the number of repeated tests, and reduce patient exposure.
9 citations
TL;DR: The ovarian shield designed in this study has significantly reduced the radiation dose to the ovaries without adversely affecting diagnostically image quality and the testicular shield has improved the accuracy positioning of the shield.
Abstract: Background: The use and effectiveness of traditional lead gonad shields in pediatric pelvic radiography has been challenged by several literatures over the past two decades. The aim of this study was to develop a new radioprotective gonad shields to be use in pediatric pelvic radiography. Materials and Methods: The commercially available 0.06 mm lead equivalent bismuth garment has cropped squarely and used as ovarian shield to cover the entire region of pelvis. In order to prevent deterioration of image quality due to beam hardening artifacts, a 1-cm foam as spacer was located between the shield and patients pelvis. Moreover, we added a lead piece at the cranial position of the bismuth garment to absorb the scatter radiations to the radiosensitive organs. In girls, 49 radiographs with shield and 46 radiographs without shield was taken. The radiation dose was measured using thermoluminescent dosimeters (TLDs). Image quality assessments were performed using the European guidelines. For boys, the lead testicular shields was developed using 2 cm bismuth garment, added to the sides. The prevalence and efficacy of testicular shields was assessed in clinical practice fromFebruary 2016 to June 2016. Results: Without increasing the dose to the breast, thyroid and the lens of the eyes, the use of bismuth shield has reduced the entrance skin dose(ESD) of the pelvis and radiation dose to the ovaries by 62.2% and 61.7%, respectively (P<0.001). Image quality remained diagnostically acceptable in all shielded and non-shielded images, without non-diagnostic or poor quality image. In boy patients, the prevalence of shielding in lead and developed testicular shields were obtained 63.25% and 19.74%, respectively; the accuracy positioning of the shield 90% and 34%, as well as. Conclusion: The ovarian shield designed in this study has significantly reduced the radiation dose to the ovaries without adversely affecting diagnostically image quality. The testicular shield has improved the accuracy positioning of the shield. These developed shields have potential to be use in clinical practice.
7 citations
Cites background from "The Evaluation of Conventional X-ra..."
...Access to the good image quality associate with low patients dose is the philosophy of any radiological examination (42, 43)....
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References
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TL;DR: This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing, and explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose.
Abstract: The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems.
159 citations
"The Evaluation of Conventional X-ra..." refers background in this paper
...Some researchers have only focused on patient dose optimization [10-13], whereas some have examined both patient dose and image quality in radiographic devices [14-16]....
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TL;DR: Reference values (RVs) are recommended by the American Association of Physicists in Medicine for four radiographic projections, computed tomography, fluoroscopy, and dental radiography to compare radiation doses from individual pieces of radiographic equipment with doses from similar equipment assessed in national surveys.
Abstract: Reference values (RVs) are recommended by the American Association of Physicists in Medicine for four radiographic projections, computed tomography, fluoroscopy, and dental radiography. RVs are used to compare radiation doses from individual pieces of radiographic equipment with doses from similar equipment assessed in national surveys. RVs recommended by the American Association of Physicists in Medicine have been developed from the Nationwide Evaluation of X-ray Trends survey performed by the state radiation protection agencies with the cooperation and support of the U.S. Food and Drug Administration, the Conference of Radiation Control Program Directors, and the American College of Radiology. The RVs selected by the American Association of Physicists in Medicine represent, approximately, the 80th percentile of the survey distributions. Consequently, equipment exceeding the RVs is using higher radiation doses than is 80% of the equipment in the surveys. Radiation doses for specific projections, with standard phantoms, should be measured annually, as recommended by the American College of Radiology. When the RVs are exceeded, the medical physicist should investigate the cause and determine, in cooperation with the responsible radiologist, whether these doses are justified or the imaging system should be optimized to reduce patient radiation doses. RVs are a useful tool for comparing patient radiation doses at institutions throughout the United States and for providing information about radiographic equipment performance.
142 citations
"The Evaluation of Conventional X-ra..." refers background in this paper
...Some studies have presented reference values for clinical X-ray examinations by measuring phantom dose [17]....
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TL;DR: Different concepts must be introduced for a better understanding of the tradeoffs encountered when dealing with digital radiography and ALARA.
Abstract: Image quality takes on different perspectives and meanings when associated with the concept of as low as reasonably achievable (ALARA), which is chiefly focused on radiation dose delivered as a result of a medical imaging procedure. ALARA is important because of the increased radiosensitivity of children to ionizing radiation and the desire to keep the radiation dose low. By the same token, however, image quality is also important because of the need to provide the necessary information in a radiograph in order to make an accurate diagnosis. Thus, there are tradeoffs to be considered between image quality and radiation dose, which is the main topic of this article. ALARA does not necessarily mean the lowest radiation dose, nor, when implemented, does it result in the least desirable radiographic images. With the recent widespread implementation of digital radiographic detectors and displays, a new level of flexibility and complexity confronts the technologist, physicist, and radiologist in optimizing the pediatric radiography exam. This is due to the separation of the acquisition, display, and archiving events that were previously combined by the screen-film detector, which allows for compensation for under- and overexposures, image processing, and on-line image manipulation. As explained in the article, different concepts must be introduced for a better understanding of the tradeoffs encountered when dealing with digital radiography and ALARA. In addition, there are many instances during the image acquisition/display/interpretation process in which image quality and associated dose can be compromised. This requires continuous diligence to quality control and feedback mechanisms to verify that the goals of image quality, dose and ALARA are achieved.
69 citations
"The Evaluation of Conventional X-ra..." refers background in this paper
...Some researchers have only focused on patient dose optimization [10-13], whereas some have examined both patient dose and image quality in radiographic devices [14-16]....
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TL;DR: Experiences in implementation of a programme to reduce doses to patients from radiographic examinations are described, which revealed a wide range in other factors such as transmission of X-ray table tops and results are being used in planning replacement of equipment.
Abstract: Experiences in implementation of a programme to reduce doses to patients from radiographic examinations are described. A preliminary survey of entrance doses for selected examinations, calculated from mean exposure factors, identified equipment and examinations requiring attention. Subsequently more detailed studies were carried out with thermoluminescent dosemeters (TLDs). Results were coordinated with the aid of a database, which was used to monitor the agreement between dose calculations and TLD measurements. Surveys highlighted that doses from lumbar and thoracic spine examinations were high throughout the region. Reductions of 26-36% in entrance dose and 20-25% in effective dose were achieved by raising tube potentials for these examinations. This gave a reduction in annual collective dose of 4 man-Sv with no cost implication. In some departments dose charts were used to support the purchase of new screens. Surveys revealed a wide range in other factors such as transmission of X-ray table tops and results are being used in planning replacement of equipment.
41 citations
"The Evaluation of Conventional X-ra..." refers background in this paper
...According to earlier reports, increasing the tube voltage (kVp) from 8-1 (Table 1) 3 in lumbar spine and thoracic examinations results in a dose reduction of 26-36% [19]....
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TL;DR: Assessment of patient doses for the most frequent X-ray examinations for the first time in Serbia and Montenegro confirms that the dose level for complex fluoroscopy investigations is closely related to the technique and individual patient variation in terms of fluoroscope time and number of radiography exposures.
Abstract: The objective of this work is to assess patient doses for the most frequent X-ray examinations for the first time in Serbia and Montenegro. A total of 510 procedures for 11 different examination categories in 3 general hospitals were analysed. Mean and median entrance surface air kerma (ESAK) and kerma area product (KAP) values followed by mean effective doses were reported. Using X-ray tube output data, ESAK for each radiographic examination was calculated, as well as the effective dose for each patient. Except for chest PA examination, all estimated doses are less than stated European and International Atomic Energy Agency (IAEA) reference levels for simple radiographic examinations. For complex examinations involving fluoroscopy and radiography total KAP was measured and contributions from fluoroscopy and radiography were assessed. The study of KAP confirms that the dose level for complex fluoroscopy investigations is closely related to the technique and individual patient variation in terms of fluoroscopy time and number of radiography exposures. The obtained values are comparable to those reported in the UK. Survey data are aimed aid development of a national quality control and radiation protection programme for medical exposures.
32 citations