Dose evaluation for paediatric chest x-ray examinations in Brazil and Sudan: low doses and reliable examinations can be achieved in developing countries

ESTABLISHMENT OF RADIATION DOSES FOR PEDIATRIC X-RAY EXAMINATIONS IN A LARGE PEDIATRIC HOSPITAL IN TURKEY

Pediatric patients are more sensitive to ionizing radiation when compared with adults. The aim of this study was to evaluate the radiation doses for some common pediatric x-ray examinations performed with various digital radiography systems. Quality control tests of the digital radiography systems were carried out according to international published protocols before the pediatric dose measurements. Radiation dose measurement was performed by using the x-ray tube outputs and thermoluminescent dosimeter dose measurement methods. In the present study, radiation doses were assessed for 247 chest, 230 pelvis, 194 skull and 73 abdomen x-ray examinations and in total 744 pediatric patients doses were measured. Pediatric patients were classified into four age groups 0-1, 1-5, 5-10 and 10-15 years as given by European Commission guidance. Effective doses were determined for each examination using a PCXMC 2.0 Monte Carlo program. The mean measured entrance skin doses for the age interval 1-5 years and AP projection by using tube output measurement methods were 149 µGy for chest, 304 µGy for pelvis, 387 µGy for skull and 199 µGy for abdomen examinations. The radiation dose results obtained in this study were in the range of the published results in the literature.

Assessment of Pediatrics Radiation Dose from Routine X-Ray Examination at Jimma University Hospital, Southwest Ethiopia

BACKGROUND

Given the fact that children are more sensitive to ionizing radiation than adults, with an increased risk of developing radiation-induced cancer, special care should be taken when they undergo X-ray examinations. The main aim of the current study was to determine Entrance Surface Dose (ESD) to pediatric patients arising from routine x-ray examination in the Radiology Department of Jimma University Specialized Hospital (JUSH).

METHODS

Descriptive cross-sectional study was conducted on pediatric patients less than 15 years of age who visited to seek x-ray examinations in JUSH. In this study, chest (AP), skull (AP), Abdomen (AP) and Pelvic (AP) x-ray examinations were analyzed. Radiographic exposure factors were recorded in each examination. ESD was calculated using exposure parameters. The calculated ESD values were weighed against the Diagnostic Reference Level (DRL) recommended doses and similar published studies. Comparison was made among different age groups through mean comparison.

RESULT

The obtained ESD values were mostly higher than the values in internationally published studies and DRL for all age groups. For chest AP, the mean ESD values were 1.82mGy which is higher than similar studies in Nigeria (0.642Mgy), Brazil (o.o62mGy) and NRPB (0.050mGy) for ages of 0-1 years.

CONCLUSION

The higher pediatric patient dose obtained in this study is a further indicator that doses delivered to pediatric patients are not according to ALARA principle, and there is a need to optimize service and patients' radiation exposure in JUSH in particular and in Ethiopia in general.

A dose index as a tool to estimate paediatric patient doses in digital projection radiography

Radiation exposure during childhood is estimated to have a lifetime risk up to seven times greater than exposures at adult age. Therefore, paediatric patient dose monitoring is a major concern in radiology. The aim of this study is to evaluate the validity of a dose index, displayed at the digital imaging and communication in medicine (DICOM) header of the images, as a dosimetric quantity to estimate the entrance surface dose (ESD) for each procedure. It was carried out over a sample of 156 paediatric patients who underwent a chest examination. National Radiation Protection Board Report 318 model was used to categorise patients by age and to estimate their thickness. Corrected dose index values were compared with calculated ESD, estimated from tube output and radiographic technique. The deviation between both values remained within 2% for every age group, except for patients up to 1 y. Therefore, the index could be used to estimate ESD, allowing to manage greater patient dose databases.

Pediatric radiography entrance doses for some routine procedures in three hospitals within eastern Nigeria

A survey of the entrance surface doses in the routine radiography of children in eastern Nigeria has been carried out in three hospitals, using thermoluminescence detectors. Chest, abdomen, lumbar spine, skull and pelvis were covered in this study. Findings reveal that doses are higher than the recommended reference values elsewhere, as well as values reported for Sudan. The mean percentage difference in entrance doses for chest radiography for this study and an earlier one carried out for three hospitals in the west of Nigeria is about 44.7%. The high doses are traceable to a lack of standardization in procedure, resulting in use of low tube voltages and high currents for examination, as well as the status of facilities in the area. Recommendations are made for immediate corrective measures to lower the doses.

Measurement of entrance skin dose and estimation of organ dose during pediatric chest radiography

Entrance skin dose (ESD) was measured to calculate the organ doses from the anteroposterior (AP) and posteroanterior (PA) chest x-ray projections for pediatric patients in an Indian hospital. High sensitivity tissue-equivalent thermoluminescent dosimeters (TLD, LiF: Mg, Cu, P chips) were used for measuring entrance skin dose. The respective organ doses were calculated using the Monte Carlo method (MCNP 3.1) to simulate the examination set-up and a three-dimensional mathematical phantom for representing an average 5-y-old Indian child. Using this method, conversion coefficients were derived for translating the measured ESD to organ doses. The average measured ESDs for the chest AP and PA projections were 0.305 mGy and 0.171 mGy, respectively. The average calculated organ doses in the AP and the PA projections were 0.196 and 0.086 mSv for the thyroid, 0.167 and 0.045 mSv for the trachea, 0.078 and 0.043 mSv for the lungs, 0.110 and 0.013 mSv for the liver, 0.002 and 0.016 mSv for the bone marrow, 0.024 and 0.002 mSv for the kidneys, and 0.109 and 0.023 mSv for the heart, respectively. The ESD and organ doses can be reduced significantly with the proper radiological technique. According to these results, the chest PA projection should be preferred over the AP projection in pediatric patients. The estimated organ doses for the chest AP and PA projections can be used for the estimation of the associated risk.

Evaluation of paediatric X-ray doses in Moroccan university hospitals

This work evaluates the entrance skin dose (ESD), the body organ dose (BOD) and the effective dose (E) for chest X-ray exposures of paediatric patients. Two Moroccan university hospitals in Rabat, composed of two departments, and one in Casablanca with one paediatric compartment has been considered. For reasons of confidentiality, the departments are named A, B and C. Patients were divided into four age groups: 0-1, 1-5, 5-10 and 10-15 y, so that the results could be compared with previous published data found in the literature. The results have been calculated with the use of the Dose Cal software. Results of mean ESD for the age interval 1-5 y and antero-posterior (AP) projection are: 162 µGy for hospital A, 91 µGy for hospital B and 105 µGy for hospital C. The diagnostic reference levels (DRLs) of 100 µGy for this age range is exceeded in hospital A, while in the other two hospitals results were within the DRL and comparable with the results found in Brazil, Soudan, Nigeria and other radiological centres inpean Countries. The results of BOD and E showed that for the three departments, the BOD varies in the same proportion as the ESD. The highest values are those of hospital A. For the PA examination, the dose is reduced compared with the AP projection, especially for sensitive organs.

Radiation doses from some common paediatric X-ray examinations in Sudan

Radiation doses to patients from some common paediatric X-ray examinations were studied in three hospitals in Khartoum state, Sudan. Entrance surface dose (ESD) was determined from exposure settings using DosCal software. Totally, 459 patients were included in this study. Mean ESDs obtained from anteroposterior projection for chest, skull, abdomen and pelvis for neonates falls in the range of 52-100, 115-169, 145-183, 204-242 microGy, respectively. For a 1-y-old infant, mean ESD range was 80-114, 153-202, 204-209, 181-264 microGy, respectively. Some doses for neonates and infants were exceeding the reference doses by >20%. The results highlighted that a good technique has to adhere to guidelines necessarily. As demonstrated elsewhere, patients' doses were high in departments using single-phase generators compared with those using constant potential. The results presented will serve as a baseline data needed for deriving reference doses for paediatric X-ray examinations in Sudan.

Dose and image quality optimization in neonatal radiography

In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening diseases, the timely diagnosis and treatment of which may require a large number of radiographs. Increased neonatal radiosensitivity and longer life expectancy increase the risk of radiation-induced cancer, which emphasizes the importance of minimizing dose while maintaining clinically satisfactory image quality. An optimization study on radiation dose and image quality in neonatal radiography is presented. Neonates were categorized into four groups depending on birthweight. For a total of 378 chest and chest-abdomen radiographs, exposure parameters were recorded. Entrance surface dose (ESD) was estimated and dose-area product (DAP) was measured. Image quality evaluation was performed by two observers and was based on the visibility of certain anatomical features and catheters placed during treatment using a five-grade scale. ESD values increased with neonatal weight and demonstrated wide variation (16.4-76.9 microGy, mean 38.2 microGy). A wide variation was also observed in DAP values (1.2-15.0 mGycm2, mean 7.2 mGycm2). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image (score >70%) using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The majority of estimated ESDs are in accordance with the reference level of 50 microGy recommended by the National Radiological Protection Board for neonatal radiography. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight.

Paediatric dose measurement in a full-body digital radiography unit

BACKGROUND

Ionizing radiation has a detrimental effect on the human body, particularly in children. Thus it is important to minimize the dose. Linear slit-scanning X-ray units offer the possibility of dose reductions. In order to further develop linear slit-scanning radiography, the dose needs to be accurately calculated for various examinations.

OBJECTIVE

To measure the entrance dose (free-in-air) and calculate the effective doses for various radiological examinations in children on Lodox Statscan and Shimadzu radiography units.

MATERIALS AND METHODS

Entrance doses (free-in-air) were measured using a dose meter and ionization chamber on the Statscan and Shimadzu units at two South African hospitals. The entrance doses were measured for a number of common examinations and were used to compute the effective dose using a Monte Carlo program.

RESULTS

The standard deviation of the entrance doses was in the range 0-0.6%. The effective dose from the Statscan unit was well below that from the Shimadzu unit as well as that found in other radiological studies from around the world in children. The one exception was chest examination where the dose was similar to that in other studies worldwide due to the use of Chest AP projection compared to Chest PA used in the comparative studies.

CONCLUSION

Linear slit-scanning systems help reduce the dose in radiological examinations in children.

Optimising the use of computed radiography in pediatric chest imaging

The objective of this study was to analyze image quality of chest examinations in pediatric patients using computed radiography (CR) obtained with a wide range of doses to suggest the appropriate parameters for optimal image quality. A sample of 240 chest images in four age ranges was randomly selected from the examinations performed during 2004. Images were obtained using a CR system and were evaluated independently by three radiologists. Each image was scored using criteria proposed by the European Guidelines on Quality Criteria in Pediatrics. Mean global scoring and scoring of individual criteria more sensitive to noise were used to evaluate image quality. Agfa dose level (DL) was in the range 1.20 to 2.85. It was found that there was not significant correlation (R < 0.5) between image quality and DL for any of the age ranges for either global score or for individual criteria more related to noise. The mean value of DL was in the ranges 1.9-2.1 for the four age bands. From this study, a DL value of 1.6 is proposed for pediatric CR chest imaging. This could yield a reduction of approximately a factor of 2.5 in mean patient entrance surface doses.

Entrance surface doses to patients undergoing selected diagnostic X-ray examinations in Sudan

The aim of the study was to evaluate the entrance surface doses (ESDs) to patients undergoing selected diagnostic X-ray examinations in major Sudanese hospitals. ESD per examination was estimated from X-ray tube output parameters in four hospitals comprising eight X-ray units and a sample of 346 radiographs. Hospital mean ESDs estimated range from 0.17 to 0.27 mGy for chest AP, 1.04-2.26 mGy for Skull AP/PA, 0.83-1.32 mGy for Skull LAT, 1.31-1.89 mGy for Pelvis AP, 1.46-3.33 mGy for Lumbar Spine AP and 2.9-9.9 mGy for Lumbar Spine LAT. With exception of chest PA examination at two hospitals, mean ESDs were found to be within the established international reference doses. The results are useful to national and professional organisations and can be used as a baseline upon which future dose measurements may be compared.

Survey of doses and frequency of X-ray examinations on children at the intensive care unit of a large reference pediatric hospital

OBJECTIVE

This work aims to evaluate the entrance surface dose (ESD), the body organ dose (BOD) and the effective dose (E) resulting from pediatric radiological procedures with the use of portable X-ray equipments.

MATERIALS AND METHODS

The software DoseCal was used to evaluate the doses imparted to patients. The children were classified according to their weight and age groups, and the study included three sectors of the intensive care unit of a large reference pediatric hospital in Rio de Janeiro.

RESULTS

A total of 518 radiographs have been performed, (424 for chest and 94 for abdomen). The statistical data were compared with previously published results. The BOD is presented for the most exposed organs.

CONCLUSION

The mean value of ESD and E varied widely among neonates. The highest number of radiographs per infant peaked 33 for chest examination in the age group 0-1 year.

Paediatric x-ray examinations in Rio de Janeiro

This work presents the results of a dose survey performed for paediatric patients and carried out in two large paediatric public hospitals in Rio de Janeiro city. The entrance surface dose (ESD) and the effective dose (ED) were evaluated for chest, skull, abdomen, lumbar spine, cervical spine and pelvis in antero-posterior (AP), postero-anterior (PA) and lateral (LAT) projections. For each examination, four age groups 0-1, 1-5, 5-10 and 10-15 years were studied. The DoseCal software was used to calculate these doses. Wide variations for the same type of examination and projection have been detected. These variations were evident, in Brazil, from previous work. In spite of the present results being still preliminary, they can give an idea of what paediatric ESDs are like in Brazil. Also, with respect to the entrance surface dose, some of the results are above the reference levels, which cause high ED, as well. On the other hand, the wide range of ESD reflects the disparity of radiographic techniques and demonstrates that the ALARA principle is not being applied in Brazilian hospitals and becomes a concern in terms of public health.