Ana Cecília Pedrosa de Azevedo

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

Radiation protection in paediatric radiology deserves special attention since it is assumed that children are more sensitive to radiation than adults. The aim of this work is to estimate the entrance skin dose (ESD), the body organ dose (BOD) and the effective dose (E) for chest x-ray exposure of paediatric patients in five large units, three in Sudan and two in Brazil, and to compare the results obtained in both countries with each other and with other values obtained by some European countries. Two examination projections have been investigated, namely, postero-anterior (PA) and antero-posterior (AP). The age intervals considered were: 0-1 year, 1-5 years, 5-10 years and 10-15 years. The results have been obtained with the use of a software called DoseCal. Results of mean ESD for the age interval 1-5 years and AP projection are: 66 microGy (Instituto de Pediatria e Puericultura Martagão Gesteira--IPPMG Hospital), 41, 86 and 68 microGy (Instituto Fernandes Figueira--IFF Hospital), 161 microGy (Omdurman Hospital), 395 microGy (Khartoum Hospital) and 23 microGy (Ahmed Gasim Hospital). In the case of the IFF Hospital, the results refer, respectively, to rooms 1, 2 and for the six mobile equipments. The reference dose values given by the European Guidelines were exceeded in the Khartoum Hospital whilst in all the other hospitals results obtained were below CEC reference values and comparable with the results found in Sweden, Germany, Spain and Italy. The mean E for the same age interval was 11 microSv in the IPPMG, 6, 15 and 11 microSv in the IFF, respectively for rooms 1, 2 and the 6 mobiles, 25 microSv in the Omdurman Hospital, 45 microSv in the Khartoum Hospital and 3 microSv in the Ahmed Gasim Hospital. These are some examples of the large discrepancies that have been detected in this survey.

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.

Dose measurements using thermoluminescent dosimeters and DoseCal software at two paediatric hospitals in Rio de Janeiro.

A dosimetric survey in paediatric radiology is currently being carried out at the paediatric units of two large hospitals in Rio de Janiero city: IPPMG (Instituto de Pediatria e Puericultura Martagão Gesteira, University Hospital of Federal University of Rio de Janeiro) and IFF (Instituto Fernandes Figueira, FIOCRUZ). Chest X-ray examination doses for AP, PA and LAT projections of paediatric patients have been obtained with thermoluminescent dosimeters (TLDs) and with use of a software package DoseCal. In IPPMG and IFF 100 patients have been evaluated with the use of the TLDs and another group of 100 patients with the DoseCal software. The aim of this work was to estimate the entrance skin dose (ESD) for frontal, back and lateral chest X-rays exposure of paediatric patients. For ESD evaluation, three different TL dosimeters have been used, namely LIF:Mg,Ti (TLD100), CaSO4:Dy and LiF:Mg,Cu,P (TLD100H). The age intervals considered were 0-1, 1-5, 5-10 and 10-15 years. The results obtained with all dosimeters are similar, and it is in good agreement with the DoseCal software, especially for AP and PA projections. However, some larger discrepancies are presented for the LAT projection.

Exposição de pacientes e qualidade da imagem em radiografias de tórax: uma avaliação crítica

OBJECTIVE: Entrance skin dose, effective dose, and imaging quality in chest radiographs of adult patients have been evaluated. MATERIALS AND METHODS: The study has been developed in eight institutions - seven public hospitals (two of them philanthropic institutions) and one private - in the cities of Agra dos Reis, Cabo Frio, Campos dos Goytacazes, Itaperuna, Niteroi, Recife and Rio de Janeiro. Entrance skin dose and effective dose have been evaluated in 735 chest radiographs obtained in posteroanterior/anteroposterior and lateral projections. As regards imaging criteria, 44 radiographs have been evaluated. RESULTS: Variations of up to nine times in entrance skin dose, and six times in effective dose have been detected for a same type of projection. Also, significant discrepancies have been found in values resulting from radiographic techniques employed. Besides, imaging quality has not been good since the rate of compliance with imaging criteria was only 55%. CONCLUSION: There is a pressing need for improvement/standardization of procedures in conventional radiology; this can be achieved by implementing a quality control and assurance program in the department of radiology, including training of technicians, x-ray equipment calibration, and sensitometric control of films processors.

Análise e gerenciamento de efluentes de serviços de radiologia

OBJECTIVE: With the aim of reducing and preventing environmental damages, handling and disposing practices of chemical effluents from radiology departments were investigated and a service management model was created in order to obtain financial resources for the department. MATERIALS AND METHODS: The proposed model, based on the evaluation of chemical effluents from automatic processors of radiographic films, showed that fixer reprocessing can be an adequate choice to solve environmental and financial problems in these departments. This model also emphasizes that compliance with management guidelines should be observed, i.e. other effluents (developer and water) must be chemically treated before disposal in the natural environment. The economical analysis has confirmed that the income originated from commercializing the silver (of which concentration ranges from 3.5 to 10.2 g/l), recovered from the used fixer, in addition to the income from the reuse of the fixer (after its recovery), is in the worst scenario (when the silver concentration is 3.5 g/l) enough to cover all the expenses with the implementation of the project. CONCLUSION: The proposed model can be a good choice for solution of environmental and financial problems. Moreover, it is ecologically correct, a potential source of financial resources to radiology departments, and can be applied to other institutions due to the similarity of problems and resources.

Avaliação dos padrões de dose em radiologia pediátrica

Neste trabalho avaliou-se o produto dose area e estimou-se a dose na entrada da pele em exames pediatricos, cujos resultados mostraram valores, em media, 100% acima do adotado como referencia para a realizacao deste trabalho (0,070 mGy). Simultaneamente, fez-se a afericao dos parâmetros tecnicos dos equipamentos usados para a obtencao das imagens radiograficas. Os resultados revelaram que o desempenho dos equipamentos esta de acordo com a legislacao sanitaria vigente. Logo, as doses elevadas foram atribuidas ao emprego de tecnicas de baixa tensao e a falta de especializacao para a realizacao de exames pediatricos. Realizaram-se medidas das doses absorvidas na regiao gonadal durante as exposicoes radiograficas utilizando-se dosimetros termoluminescentes, que se mostraram inadequados para a obtencao destas medidas. Usou-se entao uma câmara de ionizacao e os valores obtidos revelaram que as doses absorvidas sobre a regiao gonadal estao abaixo dos limites que poderiam causar esterilidade temporaria ou permanente.

Survey of Image Quality and Radiographic Technique of Pediatric Chest Examinations Performed in Brazil

This work presents the results of a survey of Entrance Surface Air Kerma (Ke) values, image quality and radiographic exposure parameters used in pediatric chest examinations performed in Brazil. The study is part of the activities of the IAEA Regional Project RLA/9/057 whose objective is to optimize the radiological protection of patients in diagnostic and interventional radiology, nuclear medicine and radiotherapy. The survey was performed in four hospitals in Brazil. The study group consisted of 420 pediatric patients from two age groups (Group I- from two days to one year, Group II- from four to six years of age) undergoing chest PA/AP examinations. At the time of the examination the exposure parameters (kVp, mAs, focal-spot-to-film distance, etc.) and patient information (gender, height, weight and age) were recorded. The radiographic image quality was evaluated by the local radiologist based on the European Guidelines on Quality Criteria for Diagnostic Radiographic Images in Pediatrics. The results showed that the exposure parameters used on newborn patients were in the majority outside the 60-65kV range recommended by the European Guidelines for a good radiographic practice. In the case of examinations of patients with age between 4 and 6 years, 80% were performed with a peak tube voltage within the 60-80 kV range, as recommended by the European Guidelines. The Ke values, for both patient groups showed a wide dispersion, ranging from 30.7 μGy to 163.8 μGy for the newborn patients and from 34.5 μGy to 236.6 μGy for infant patients. It is possible to conclude that, in the Brazilian hospitals participating in this project, the radiographic techniques of pediatric chest images and the radiation protection need to be optimized.

LINCE: a practical darkroom QC device

Diagnostic radiology departments are of increasing importance in hospitals nowadays. The implementation of a Quality Control Program (QCP) in hospitals and clinics is of major importance and contribute to the production of an optimal radiographic image. One of the main aspects of the QCP is the correct development of the radiographic images. Therefore, hygienic conditions of the darkrooms as well as best cleaning and maintenance of accessories (screens and cassettes) are of major importance. The presence of dust, grease and other impurities inside the darkroom and in the accessories contribute to degrade image quality and produce artifacts on the final image. LINCE is an inspection light that was constructed to be used as a complementary device in QC of diagnostic radiology darkrooms. It is composed of two bulbs: one black light and one UV light. The black light is used to check the cleaning inside the darkrooms since it enhance dust particles that become easily seen when reached by this light. The UV light is used to check the cleaning of radiographic screen as well as their integrity. The UV light enhances grease, fingerprints and scratches in the screens. The LINCE is of low cost, portable, light, of easy handling and can be used by personnel in charge of cleaning and maintenance of darkrooms and accessories of radiology departments. The use of LINCE will certainly contribute to improve the image quality as well as to reduce the presence of image artifacts. The LINCE is patent pending in Brazil with registration number 0000220503067803 dated of 07/25/2005.

Fluoroscopy examinations in pediatrics in Rio de Janeiro

An extensive program of doses’ evaluation in pediatric radiology is being developed in Rio de Janeiro. Data presented in this survey, were collected from October 2005 to February 2006, in a large dedicated public pediatric hospital in Rio de Janeiro city. The radiation doses were collected using a DIAMENTOR that has an ionization chamber directly attached to the X ray tube exit and connected to a display and a computer. One hundred and twelve patients took part in the evaluation and were classified according to age ranges: 0–1, 1–5, 5–10, 10–15 years. Several kinds of examinations that use fluoroscopy have been studied and the longest mean examination time per patient was for barium enema examination (∼ 9 minutes), seriography (∼8 minutes) and uretrocystography (6.5 minutes). The highest mean number of radiographs per patient was for uretrocystography (∼ 15), seriography (∼ 13) and genitography (∼ 13). The highest mean values of ESD (Entrance Surface Dose) were for abdomen (102.1 µGy), and skull (87,6 µGy). The Dose Area Product (DAP) showed the mean highest value for the uretrocystography examination (24.2 cGy.cm2) followed by the abdomen examination that presented a mean DAP value of 18.3 cGy.cm2. It has been observed that fluoroscopy is being used to locate the patient even in examinations that do not require fluoroscopy such as abdomen and skull. The results obtained in this survey will contribute to guide and advice the radiologists about the doses being imparted to the pediatric patients as well as to alert them about unnecessary irradiation helping them to reduce irradiation time in fluoroscopy procedures.