Diagnostic X-ray Installations Research Articles

An Enumeration Survey on Diagnostic X-Ray Generators and Essential Safety Parameters in Mizoram, India

Introduction: Best radiography practice involves operational optimal machine performance, delivering cost-effective healthcare services under appropriate safety conditions for workers and the public. The present study aimed to investigate the safety status of diagnostic X-ray installations in Mizoram, India. Material and Methods: Linearity of time (sec), linearity of current (mA), output reproducibility, table dose (μGy/mAs), peak voltage (kVp) accuracy, and 16 essential safety parameters of 135 X-ray machines were considered in this study. A battery-operated dosimeter and wide-range digital kVp meter were used to measure output radiation and effective peak potential of X-ray tube. Data analysis was performed using SPSS software to obtain the mean, standard deviation, and coefficient of variation. Results: Among different electronic parameters, 59.2% linearity of time, 82.6% linearity of current, 89.7% kVp accuracy, 35.1% output reproducibility, and 92.8% table dose were beyond the acceptable limits. Based on 16 essential safety parameters, it was observed that 98.7% of X-ray machines did not receive proper quality assurance test, 1.9% of the installations employed lead-line patient entrance doors, 46.8% of the machines were operated without any protective barriers and 83.1% of the units were operated without personnel monitoring service. Conclusion: The present study had concluded with more problems than the previous studies in different parts of the world in this regard. Due to the absence of proper quality control (QC) programs, many installations did not follow standard installation guidelines. The authors recommended that proper QC should be implemented by the frequent monitoring of each and every diagnostic X-ray installation.

Evaluation of radiation doses at diagnostic X-ray control panels and outside patient entrance doors in Aizawl district, India.

The purpose of this research was to measure the radiation level and estimate the dosage at the control panel (CP) and outside the patient entrance door (PED) of diagnostic X-ray installations. This is important for ensuring the safety of workers and the public, particularly in the study area, where there is no proper radiation monitoring service. A water phantom, 10-L fresh water in a plastic container, was used as the source of scattered radiation. Using an ion-chamber survey meter, the stray radiation rate was measured at the CP and outside the PED for both chest and couch missions. The CPs were fully covered by a protective barrier, providing a negligible exposure rate (i.e., 0.07-4.2mR/h for chest and 0.21-3.8mR/h for couch). By contrast, installations that did not properly cover the CP showed relatively high exposures (from 18 to 205mR/h for chest and 2.4-270mR/h for couch). The radiation rates outside the PED in installations having lead-lined doors were negligibly low; whereas, in installations having no lead-lining, exposure rates reached as high as 95 and 110mR/h for chest and couch missions, respectively. The occupational doses were well below the Atomic Energy Regulatory Board dose limit (i.e., 40mR/week). However, excessive doses were observed in public spaces outside the PED, compared with the dose limit for the public (i.e., 2mR/week).

Study on the intensity of radiation attenuated by protective barriers in diagnostic X-ray installations

The main objective of the present study is to find out the intensity of radiation attenuated by different types of patient entrance doors (PED) as well as control panel (CP) protective barriers in diagnostic X-ray installations. To measure the intensity of ionizing radiation, ion chamber survey meter was used; all measurements were performed in freeze mode. In setting maximum accelerating potential, minimum tube current and fixed exposure time, a water phantom was exposed through maximum field size. Radiation exposure rates were measured at CPs as well as PEDs with and without barriers. In chest mission, radiation rates with PED ranged from 0.3 µSv/h to 0.7 mSv/h and without PED 0.2 mSv/h to 1.2 mSv/h. At the same time, in couch mission, radiation rates measured behind PED ranged from 0.3 µSv/h to 2.2 mSv/h and 0.03 mSv/h to 2.25 mSv/h in front of PED. All institutions showed higher exposure rates without PED; all types of doors considerably attenuated radiation. Among different types of door, lead-lined door attenuated 99.53% in chest mission and 97.44% in couch mission. While plywood doors attenuated approximately 40% of the incident radiation, it is more or less similar as air does in every half meter away from the phantom. Radiation rates in chest missions with CP barriers ranged from 2 µSv/h to 0.38 mSv/h, while 0.4 mSv/h to 2.35 mSv/h without CP barriers. In couch missions, radiation rates measured with CP barriers varied from 4 µSv/h to 0.6 mSv/h whereas without CP barriers from 0.7 mSv/h to 5 mSv/h. There was a significant difference between radiation measured behind and in front of the CP barriers. Among them, the percentage of attenuation was high in lead and concrete barriers.

Quality Control Tests in Some Diagnostic X-Ray Units in Bangladesh

Regular implementation of quality control in diagnostic x-ray facilities is essential to provide good quality images which lead to proper diagnoses with minimum hazard and distress. Important performance tests in diagnostic radiology in Bangladesh are carried out according to a quality control protocol and the measured parameter values are compared to the relevant acceptance limits. In this work, beam alignment, field congruence, nominal focal spot, film-screen contact and half value layer for diagnostic x-ray facilities are measured by using beam alignment test tool, RMI/Victoreen collimator test tool, Bar pattern focal spot test tool, film/screen contact test tool (RMI143D), Gammex RMI step wedge and densitometer from forty different diagnostic x-ray facilities in Bangladesh. For congruence between optical and radiation fields, 77.5% are found to be within limit and 60% of facilities are within the beam alignment limit. For most of the installations, 92.5% nominal focal spot size of diagnostic x-ray machines is matched perfectly with the rating of focal spot size. In an effort to improve image quality, this study has checked the film-screen contacts of multiple facilities and found 65% to have the expected uniformity. While investigating half value layers (HVL), a measure of x-ray beam quality, it is found that none of the diagnostic x-ray installations can achieve the recommended levels. DOI: http://dx.doi.org/10.3329/bjmp.v4i1.14688 Bangladesh Journal of Medical Physics Vol.4 No.1 2011 59-66

The Challenges of Leadership in the New Era of Health Care

The first new era of health care for radiology began in 1895, at which time physicians were marveling at the recent discovery of the tubercle bacillus, the ability to vaccinate against anthrax, and the treatment of diphtheria with antitoxin. The tetanus bacillus and malaria parasite had recently been isolated, and the thermometer, laryngoscope, and ophthalmoscope had come into widespread use. In December of that year, Wilhelm Conrad Roentgen forever changed the practice of medicine with his discovery of the x-ray, and the next new era of health care was born [1,2]. Between 1896 and 1930, x-ray equipment was initially inexpensive, and there were more than 200 diagnostic x-ray installations in the United States and Europe by 1900. Shielding was poorly understood, resulting in severe injury to radiologic personnel. However, refined equipment was rapidly developed, leading George C. Johnston, ARRS president in 1909, to remark, “The apparatus of today is obsolete tomorrow. There is a constant race between our pocketbooks and the inventive genius of the up to date manufacturer.” It was during this time that the ARRS, Radiological Society of North America, American Radium Society, and ACR were created [1,2]. Between 1930 and 1970, another new era of health care was marked by the proliferation of radiology residency programs, increasing respect for radiologists as “the doctor’s doctor,” and the development of the hospital radiology department as the central hub for direct physician consultation. This era was also enhanced by the emergence of specialization in radiation oncology, nuclear radiology, and

A Study on Some Physical Parameters Related to Image Quality and Radiation Safety in Diagnostic Radiology

Different essential radiographic parameters were studied in order to assess radiographic image quality ensuring reduction of radiation exposure in some diagnostic X-ray facilities of Bangladesh. Different parameters for developing and fixing liquid were investigated in order to eliminate improper film processing techniques. General information about intensifying screen, radiography and mammography film was also collected. X-ray tube voltage, output radiation dose and exposure time for diagnostic X-ray machines were tested to achieve significant dose reduction without loss of diagnostic information. It is found that output radiation dose varies in different diagnostic X-ray installations. 70% X-ray installations achieve the recommended value for tube voltage while 87.5% measure the exposure time appropriately. Radiation dose level at patient waiting room, dark room and around control panel was also measured. About 92.5, 85 and 77.5% installations show their results within the acceptance limit at these positions respectively which provide radiation safety for patients, workers and public in diagnostic radiology.DOI: http://dx.doi.org/10.3329/jbas.v35i1.7967Journal of Bangladesh Academy of Sciences, Vol.35, No.1, 7-17, 2011

Radiological safety status and quality assurance audit of medical X-ray diagnostic installations in India.

We conducted a radiological safety and quality assurance (QA) audit of 118 medical X-ray diagnostic machines installed in 45 major hospitals in India. The main objective of the audit was to verify compliance with the regulatory requirements stipulated by the national regulatory body. The audit mainly covered accuracy check of accelerating potential (kVp), linearity of tube current (mA station) and timer, congruence of radiation and optical field, and total filtration; in addition, we also reviewed medical X-ray diagnostic installations with reference to room layout of X-ray machines and conduct of radiological protection survey. A QA kit consisting of a kVp Test-O-Meter (ToM) (Model RAD/FLU-9001), dose Test-O-Meter (ToM) (Model 6001), ionization chamber-based radiation survey meter model Gun Monitor and other standard accessories were used for the required measurements. The important areas where there was noncompliance with the national safety code were: inaccuracy of kVp calibration (23%), lack of congruence of radiation and optical field (23%), nonlinearity of mA station (16%) and timer (9%), improper collimator/diaphragm (19.6%), faulty adjustor knob for alignment of field size (4%), nonavailability of warning light (red light) at the entrance of the X-ray room (29%), and use of mobile protective barriers without lead glass viewing window (14%). The present study on the radiological safety status of diagnostic X-ray installations may be a reasonably good representation of the situation in the country as a whole. The study contributes significantly to the improvement of radiological safety by the way of the steps already taken and by providing a vital feed back to the national regulatory body.

EXPOSURE REDUCTION THROUGH QUALITY ASSURANCE FOR DIAGNOSTIC X-RAY PROCEDURES

Traditional state x-ray inspection programs concentrate on measurement of x-ray machine parameters such as kVp and mAs, timer accuracy, collimation, etc. In 1996, the New Jersey radiation control program began a paradigm shift from the traditional inspection to an outcome-based inspection that concentrated on two indicators of performance: image quality and entrance skin exposure (ESE). Through extensive outreach and involvement of stakeholders, a new approach was designed that placed an emphasis on quality assurance. Key to the positive outcome has been the credentialing of medical physicists. On 16 January 2001, the final regulation titled "Quality Assurance Programs for Medical Diagnostic X-ray Installations" was adopted. The new regulations require that each facility using diagnostic medical x-ray equipment (including radiographic, fluoroscopic, x-ray bone densitometric, and computed tomographic) establish and carry out a quality assurance program. The new regulation specifies the quality control tests, frequencies, and standards that are part of the quality assurance program. Five years of data have been gathered. Both ESE and image quality are checked and the inspectors conduct an audit of the facility's quality assurance program. ESE has been decreased by 34% for lumbar spine, 46% for chest, and 66% for foot x-ray procedures. Image quality has improved by 22%. Quality improvement initiatives were extended to the larger dental x-ray community. Through outreach and information sharing, stakeholders were instructed in the factors that affect patient radiation exposure and image quality and were encouraged to take actions to improve in these areas.

Dose Rate Limitations of Integrating Survey Meters for Diagnostic X-Ray Survevs

Medical and health physicists are often called upon to measure scatter and evaluate shielding for diagnostic x-ray installations. As exposure times are typically too short to allow rate meters to be successfully used, integrating survey meters are often employed. Pressurized survey meters are particularly valuable because of their increased sensitivity. In practice, some integrating survey meters may give erroneous results under typical measurement conditions.

Evaluation of NCRP Report No. 49 assumptions on workloads and use factors in diagnostic radiology facilities.

A survey of modern medical institutions has been performed to measure the workload and primary beam use factors used in diagnostic x-ray installations in comparison to those suggested in Report 49 of the NCRP. Seven types of radiology installations were investigated, namely general radiographic rooms, general fluoroscopic and radiographic rooms (fluoroscopic and radiographic tubes surveyed separately), chest radiographic rooms, mammographic suites, and cardiac and peripheral angiographic suites. The radiologic technique (kVp and mAs) for each exposure performed on a total of 2396 patients was recorded either manually or by a commercially-available invasive electronic sensing system. Additionally, the direction of the primary beam during the exposure was recorded. The kVp distribution of the workload data was determined and normalized per patient for each of the seven types of installations. The total average workload per patient surveyed in each type of installation is 2.5, 13, 1.5, 0.22, 6.7, 160, and 64 mA min per patient for the above installation types. For general radiographic rooms the primary beam was directed at the floor for 69% of the total workload, with the remaining 21.5%, 6.5% and 1.6% of the workload directed toward three walls. When multiplied by the average number of patients examined weekly in each type of installation, the mean weekly workloads observed are 270, 230, 35, 44, 320, 3100, and 1400 mA min for the above-listed types of installations. Additionally, a significant fraction of the observed workloads occur at potentials much less than the kVp values typically assumed for radiation shielding.

Penetration quality measurement for standardization of radiographic image quality.

Interchange or transfer of radiographic techniques through measurement of penetration quality is discussed. The usefulness of this achievement is verified using an aluminum step wedge. Also, the procedure described provides a method for performance evaluation of kVp compensation on diagnostic x-ray installations.

Protective barriers about diagnostic x-ray installations.

The lead equivalence of structural barriers surrounding 203 diagnostic x-ray installations was measured and adequacy determined by comparison with the lead thickness specified by the ICRP for distance, nature of occupancy and workload applicable to each installation, assuming operation at 125 kVp. Barrier deficiencies were found in 9%. Protective clothing was also examined: 16 of 314 gloves and 4 of 337 aprons were defective.

Surface dose during spot-film radiography

The entrance surface dose per exposure received during spot-film radiography by a unit density phantom 2.3 cm thick was measured on approximately 60 diagnostic X-ray installations in the Province of Manitoba. The majority of these installations were equipped with automatic exposure timing devices. The surface doses observed varied by as much as a factor of 15:1. Possible reasons for these variations were discussed.

Workloads and use factors in diagnostic x-ray installations.

A report is made on the magnitude and distribution of workloads observed during the course of radiation surveys in diagnostic X-ray departments in hospitals in the Province of Manitoba. The data show that the magnitudes of the majority of these workloads were considerably lower than those quoted in tables relating to protective barrier requirements, and that the distribution of the primary beam workloads about an installation was such that suitable use factors deviated substantially from those recommended in the NCRP Report No. 34 and the Report of the Medical X-Ray Advisory Committee on Public Health Considerations in Medical Diagnostic Radiology (X-Rays).

Exposure characteristics of diagnostic X-ray machines.

Results of exposure and quality measurements carried out on 199 diagnostic X-ray installations are presented. In addition, the exposures that would be incident on the entrance surface of patients undergoing upright postero-anterior chest radiography are reported for 108 of these installations, and the exposure rates at the fluoroscope panel under conditions employed for normal gastric fluoroscopy are reported for 37 of them. A spread in radiographic exposure rates and exposure rates at the fluoroscope panel of as much as by a factor of 5 is indicated when the units are operated under similar conditions. The variation in patient exposure is even greater for chest radiography. The HVTs for practically all of the units are reported as being between 2·0 and 4·0 mm Al.