RESUMO
OBJECTIVE: To investigate the relationship between osteoporosis and nutritional status as determined by the Mini-Nutritional Assessment (MNA). DESIGN: A cross-sectional study. SETTING: Stockholm, Sweden. SUBJECTS: A total of 351 elderly free-living women (mean age 73+/-2.3 years). METHODS: MNA (range 0-30 points; <17 indicates malnutrition, 17.5-23.5 risk of malnutrition and >or=24 well nourished), measurements of bone mineral density of the left hip and lumbar spine using Hologic QDR 4500, and of the heel using Calscan DEXA-T. RESULTS: The median MNA score was 27 (range 12.5-30). One woman was classified as malnourished and 7.4% were at risk of malnutrition. Osteoporosis of the femoral neck was observed in 22% and a fracture after the age of 50 was reported by 31% of the participants. The following items in the MNA questionnaire exhibited an increased risk of having osteoporosis in the femoral neck and/or total hip: an MNA score of <27 (odds ratio (OR)=2.09; CI=1.14-3.83); a mid-arm circumference of less than 28 cm (OR=2.97; CI=1.29-6.81); and regular use of more than 3 drugs each day (OR=2.12; CI=1.00-4.50). A body weight of more than 70 kg exhibited a decreased risk of having osteoporosis (OR=0.31; CI=0.14-0.70). CONCLUSIONS: In general, the nutritional status was good in this population of free-living elderly women. Nevertheless, half of the women who displayed an MNA score <27 points had a twofold increased risk of having osteoporosis. SPONSORSHIP: Karolinska Institutet, Stockholm County Council.
Assuntos
Densidade Óssea , Fraturas Ósseas/epidemiologia , Avaliação Nutricional , Estado Nutricional , Osteoporose Pós-Menopausa/epidemiologia , Absorciometria de Fóton/métodos , Idoso , Estudos Transversais , Feminino , Avaliação Geriátrica , Fraturas do Quadril/epidemiologia , Humanos , Inquéritos Nutricionais , Razão de Chances , Osteoporose Pós-Menopausa/diagnóstico , Fatores de Risco , Suécia/epidemiologiaRESUMO
BACKGROUND: Glucocorticoid induced osteoporosis is a well-known side effect of glucocorticoid treatment. In sarcoidosis the impact on bone by glucocorticoid treatment is complex due to hormonal disturbances of calcium and vitamin-D, which by itself may cause bone loss. In this study we aimed to investigate the longitudinal impact of glucocorticoids on cortical and trabecular bone in patients with mild, recently diagnosed sarcoidosis. METHODS: Ten patients (8 females; mean age 44 (±13)) were studied during one year of glucocorticoid treatment. The assessment of mainly cortical to purely trabecular bone was made by dual X-ray absorptiometry (DXA) of the spine and hip, quantitative ultrasound of the calcaneus, and magnetic resonance relaxometry of the spine and calcaneus. Bone and hormonal measurements were performed at baseline, after 3, 6, and 12 months, and baseline, 3 weeks and 3 months, respectively. RESULTS: DXA of the spine, decreased from baseline at 6 months (P=0.01). R2' of the calcaneus decreased with time (B: -3.6;P=0.03). In the females (n=8) there was a significant decrease in DXA of the spine when comparing 3 months and 6 months (P=0.03), and 3 months and 12 months (P=0.02) and a decrease in R2'of the calcaneus from baseline to 12 months (P=0.01). There was no change in hormonal levels. CONCLUSION: Treatment of initial mild sarcoidosis with dose tapered glucocorticoid therapy only mildly affects the final trabecular and cortical bone and hormone levels. Dose tapering is an important part in glucocorticoid therapy, likely contributing to the mild effects on bone observed in this study.
Assuntos
Corticosteroides/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Prednisolona/efeitos adversos , Sarcoidose/tratamento farmacológico , Absorciometria de Fóton/métodos , Corticosteroides/uso terapêutico , Adulto , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Seguimentos , Hospitais Universitários , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Prednisolona/uso terapêutico , Estudos Prospectivos , Sarcoidose/diagnóstico , Suécia , Resultado do TratamentoRESUMO
Magnetic resonance imaging (MRI) is a promising new diagnostic modality that is well suited for the evaluation of children with hematological or oncological diagnosis. The side effects of ionizing radiation are avoided, the tomographic pathological anatomy in three orthogonal planes can be obtained, and differences between normal and abnormal tissues are often present. In order to present our preliminary clinical experience with MRI in pediatric hematology and oncology, the historical background of MRI, the technique, and possibilities for tissue characterization are reviewed.
Assuntos
Doenças Hematológicas/diagnóstico , Espectroscopia de Ressonância Magnética , Neoplasias/diagnóstico , Criança , HumanosRESUMO
Preliminary clinical experience with magnetic resonance imaging (MRI) in 28 pediatric patients with 20 different hematological diseases, benign tumors, or malignant neoplasms is presented. The clinical results are presented in the form of case presentations that are discussed in the context of alternative diagnostic imaging modalities. Also discussed are the known biological effects, or lack thereof, the need for sedation, the effect of motion, the effect of MRI on foreign metallic objects, the financial considerations, and the trends for the future of MRI. This imaging modality has many unique merits. Present difficulties should be overcome by future innovations, making MRI even more efficacious for the diagnosis of blood diseases and cancer in children.
Assuntos
Doenças Hematológicas/diagnóstico , Espectroscopia de Ressonância Magnética , Neoplasias/diagnóstico , Adolescente , Criança , Pré-Escolar , Custos e Análise de Custo , Feminino , Humanos , Espectroscopia de Ressonância Magnética/efeitos adversos , Masculino , Movimento , Tomografia Computadorizada por Raios XRESUMO
Using a new computed tomographic (CT) scanner design that uses a rapidly moving focused electron beam, 50-ms CT scans were obtained at 2 axial levels simultaneously through the hearts of 6 dogs in order to analyze left ventricular (LV) wall thickness and cross-sectional chamber area after acute occlusion of the left anterior descending coronary artery (LAD). Ten or fifteen 50-ms CT scans (rate of 17 scans/s through the middle of the left ventricle were performed in 1 second (cine acquisition) during intravenous administration of contrast medium at rest, 60 seconds after acute occlusion of the LAD, and 60 seconds after release of the occlusion. The percent extent of systolic wall thickening of the potentially ischemic anterior segment was 37 +/- 15% (+/- standard deviation) in the control state and -5 +/- 6.5% during LAD occlusion (p less than 0.01). There was no significant difference in the percent change in LV luminal area from end-diastole to end-systole between the control state (50 +/- 19%) compared with LAD occlusion (47 +/- 21%). There were no significant differences in the extent of systolic wall thickening or LV luminal area between the control state and 60 seconds after release of occlusion. The alterations in regional myocardial function during acute ischemia are characterized by wall thinning during systole in the jeopardized segment and no significant change in global LV function. These features can be assessed by cine computed tomography during a solitary heart cycle.
Assuntos
Doença das Coronárias/fisiopatologia , Contração Miocárdica , Tomografia Computadorizada por Raios X , Animais , Arteriopatias Oclusivas/fisiopatologia , Doença das Coronárias/diagnóstico por imagem , Cães , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Hemodinâmica , Fatores de Tempo , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
Bone mineral density (BMD), bone mineral content and body composition were determined in 47 middle-aged (mean age 47.9 +/- 1.1 years) women with Turner's syndrome. Bone mineral density was measured in the forearm, femoral neck and total body. The women investigated had a BMD lower than the normal mean. When expressed as Z scores (individual values compared to normal reference data matched for age, weight and sex), the median Z score of the total body was -1.23. When comparing women with the karyotype 45,X and mosaic women, the latter showed a higher BMD in all sites of measurement. Duration of hormonal replacement therapy (HRT) differed significantly between the mosaic and the 45,X women, with a longer duration in the mosaic group (20.7 +/- 2 vs 12.1 +/- 2.6 years; p < 0.01). The duration of HRT was found to be the more important factor to maintain bone mass, not the karyotype. Bone mineral density increased with years of HRT but not until after > 20 years of HRT could a significant difference be shown between the women with HRT < or = 20 years and those with HRT > 20 years. No correlation was found between BMD and body weight, body fat or percentage body fat. Whether the osteopenia found in women with Turner's syndrome is similar to that found postmenopausally or is a specific form related to the chromosome aberration remains to be investigated further. The present data support a relation to estrogen deficiency.
Assuntos
Densidade Óssea , Síndrome de Turner/metabolismo , Absorciometria de Fóton , Terapia de Reposição de Estrogênios , Feminino , Humanos , Pessoa de Meia-Idade , Mosaicismo , Fatores de Tempo , Síndrome de Turner/tratamento farmacológico , Síndrome de Turner/genética , Cromossomo XRESUMO
AIM: To study bone mass, body composition and androgenic/anabolic activity in adult women with virilizing congenital adrenal hyperplasia (CAH) treated with glucocorticoids since infancy and to relate this to the postmenarcheal glucocorticoid impact. PATIENTS AND METHODS: Thirteen adult women with virilizing CAH treated with gluco- and mineralocorticoids but otherwise medicine-free were investigated with respect to bone mineral content, body composition by dual energy X-ray absorptiometry and endocrine status. In addition an index of accumulated postmenarcheal exogenous glucocorticoid impact was calculated. Seven of the patients had regular menstrual periods, and six were oligomenorrheic but responded with withdrawal bleedings on cyclic progestagens. The data for the patients were compared with those of age-matched healthy reference subjects. RESULTS: In spite of their shorter stature, CAH patients were significantly heavier and had a significantly higher body mass index and fat/lean body mass ratio than the controls. Their bone mineral area density (BMD) was significantly lower than that of the controls. Serum concentrations of androgens were subnormal in all except two of the patients. Strong negative associations were found between BMD and the calculated index of accumulated postmenarcheal glucocorticoid dose but not between BMD and circulating androgen levels. CONCLUSION: The results indicate that glucocorticoids were administered in excess in most of the patients, resulting in subnormal levels of adrenocortical androgens, increased body fat and bone demineralization. Increased catabolic activity due to hypercortisolism rather than decreased androgenic/anabolic steroids is probably the major cause of the subnormal BMD in the treated CAH patients.
Assuntos
Hiperplasia Suprarrenal Congênita/tratamento farmacológico , Hiperplasia Suprarrenal Congênita/patologia , Composição Corporal/fisiologia , Osso e Ossos/patologia , Glucocorticoides/uso terapêutico , Absorciometria de Fóton , Adulto , Composição Corporal/efeitos dos fármacos , Densidade Óssea/efeitos dos fármacos , Feminino , Glucocorticoides/efeitos adversos , Hormônios/sangue , HumanosRESUMO
We investigated the effect of the device known as the linear accelerator flow control (linear-rise) available on some angiographic power injectors used for delivering contrast medium. Its influence on catheter tip recoil during selective arteriography was evaluated in two glass models, which simulated assessment of catheter position in visceral and cerebral arterial branches. Contrast medium was injected over a clinical range with and without the linear flow accelerator in operation. Biplane high speed video recordings simultaneously referenced time in thousandths of seconds and the catheter position. The linear flow accelerator failed to prevent, but did delay, catheter tip recoil in proportion to the prolongation of contrast medium injection time. These laboratory results conformed with the findings of catheter behavior during similar experiments in animals undergoing arteriography.
Assuntos
Angiografia/instrumentação , Cateterismo/instrumentação , Meios de Contraste/administração & dosagem , Angiografia Cerebral/instrumentação , HumanosRESUMO
A radiographic method for use in the closed-chest dog is described which allows the quantitation of segmental mechanical performance. Previous work has shown that the area of the pressure-length loop (an approximation of a stress-strain integral) is a useful measure of the mechanical work performed by a segment of myocardium. The position of radiopaque markers previously placed to define segments of myocardium is recorded by biplane cineradiography. From simultaneous measurements of left ventricular pressure the integral of pressure with respect to segment length during one cardiac cycle is calculated. An example illustrating the utility of this model for the study of regional myocardial ischemia is presented.
Assuntos
Cinerradiografia/métodos , Doença das Coronárias/fisiopatologia , Animais , Cinerradiografia/instrumentação , Doença das Coronárias/diagnóstico por imagem , CãesRESUMO
A high-speed computed tomography (CT) scanner was used for measuring flow in a phantom and in the common carotid arteries of six dogs. The general ability of the scanner to assess flow using contrast media boluses was tested with the phantom. The validated simple concept was then used in the animals. The carotid blood flow was varied with a distal occluder on one side and measured with electromagnetic flow probes in both vessels. The results are promising and demonstrate a good correlation between the high-speed CT findings and those measured with the flow probes.
Assuntos
Artérias Carótidas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Animais , Velocidade do Fluxo Sanguíneo , Artérias Carótidas/fisiologia , Cães , Modelos EstruturaisRESUMO
Angiocardiographic methods available for cardiac chamber volume measurements have been shown to be less accurate although more practical than CT for the evaluation of the LV. To explore the capability of CT for RV volume measurements, silastic casts of seven normal RV were measured by a displacement method, conventional angiocardiographic biplane methods, and CT. The displacement method used degassing beneath vacuum to remove air trapped in the casts, and the actual volumes, which varied between 62 and 188 cc, were measured by Archimedes' principle. Cast volumes measured by biplane angiogram methods displayed a varying degree of spread around the regression line, caused by the chamber's irregular shape and its variation in orientation relative to the x-ray beams. CT measurements were in all aspects significantly more accurate.
Assuntos
Angiocardiografia , Coração/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Coração/anatomia & histologia , Humanos , Modelos Anatômicos , Elastômeros de SiliconeRESUMO
OBJECTIVES: To investigate the influence of season and outdoor daylight exposure on serum levels of 25-hydroxyvitamin D (25OHD), intact parathyroid hormone (PTH), ionized calcium, and femoral neck bone mineral density (BMD). DESIGN: A 12-month, longitudinal, prospective study on a consecutively selected sample of healthy independent older people. SETTING: Men and women living in their own homes in the inner city of Stockholm (latitude 59.2 degrees N). PARTICIPANTS: Sixty-four healthy men (n = 13) and women (n = 51), age 79 to 96 (mean age 83.7) were requested to spend at least 3 hours per week outdoors during April through September. Fifteen of these, who failed to comply with the required time outdoors, constituted a separate group. Subjects with serious diseases and subjects with medication that could interfere with vitamin D metabolism or bone mineralization were excluded from the study. MEASUREMENTS: Daily dietary intakes of calcium and vitamin D were recorded on the basis of the subjects' recall. The participants kept a diary recording the time spent in sunlight and the area of skin exposed. Fasting blood samples were collected and analyzed on four occasions for 25OHD, intact PTH, and ionized calcium. BMD was determined at 6-month intervals in the femoral neck, using dual energy x-ray absorptiometry. RESULTS: At study start in the spring, 6% of the subjects had 25OHD levels below 10 ng/ml and 78% had levels below 31 ng/ml. Forty-seven percent had intact PTH levels above the upper limit of the reference range (8-51 ng/L). Seasonal variations in the serum levels of 25OHD (P <.001), intact PTH (P <.001) and ionized calcium (P <.001) were observed only in the group with > or =3 hours of weekly outdoor daylight exposure. The 25OHD levels in autumn were positively correlated with the number of hours spent outdoors during the preceding summer (r = 0.63, P <.001). In the whole group and in the group with weekly outdoor exposure of > or =3 hours, there were no significant changes detectable in mean values of femoral neck BMD during the study year. Femoral neck BMD, expressed as Z-score, was significantly and positively correlated with serum 25OHD (r = 0.38, P =.003 after summer; r = 0.37, P =.003 after winter). CONCLUSION: The seasonal changes in serum levels of 25OHD, PTH, and ionized calcium and the positive correlation between femoral neck BMD and 25OHD indicate that regular outdoor daylight exposure during the summer could enhance calcium homeostasis and possibly bone health, even among very old people living at northerly latitudes.
Assuntos
Densidade Óssea , Hormônio Paratireóideo/sangue , Estações do Ano , Luz Solar , Vitamina D/análogos & derivados , Vitamina D/sangue , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Feminino , Colo do Fêmur , Humanos , Masculino , Estudos Prospectivos , Análise de Regressão , Estatísticas não Paramétricas , Suécia , Fatores de TempoRESUMO
RATIONALE AND OBJECTIVES: This study investigates how magnetic resonance (MR) signal and T2* of trabecular bone are affected by chemical shift. METHODS: Five pigs were sacrificed, and 150 gradient-echo MR images with increasing echo times (TEs) were obtained of the lumbar spine. Two vertebrae were excised, defatted, and imaged. Commercial fat-protein emulsions with 40%, 27%, and 15% concentrations of fat were studied. Regions of interest in subcutaneous fat (n = 3), bladder (n = 4), vertebral body (n = 10), and defatted vertebral body (n = 10) were used to study decay of signal intensity. RESULTS: MR signal intensity of the vertebrae decreased with a superimposed modulation. The periodicity was 4.65 msec (range, 4.60-4.68 msec). At a TE of 0 msec, a phase shift of 24 degrees (range, 14 degrees-37 degrees), which corresponds to a shift in TE of 0.31 msec at 1.5 T, was present. In the fat-protein emulsions, the amplitude of the modulation increased with the amount of fat. CONCLUSION: Chemical shift and the amount of fat affects T2* measurements.
Assuntos
Vértebras Lombares/química , Imageamento por Ressonância Magnética , Tecido Adiposo/química , Animais , Água Corporal/química , Medula Óssea/química , Periodicidade , SuínosRESUMO
RATIONALE AND OBJECTIVES: The authors used magnetic resonance (MR) imaging to investigate the correlation between T2* measurements of trabecular bone and the ultimate compressive strength of lumbar porcine vertebrae. METHODS: Five pigs that weighted 25-32 kg were sacrificed and imaged with a 1.5-T MR system. T2* of the lumbar vertebrae was measured from gradient-echo images. The vertebrae were individually compressed at a fixed speed in the direction of the spine until crushed. The maximum load a vertebra could resist was recorded. RESULTS: T2* ranged from 7.1 to 14.5 msec. T2* determined from 5-mm coronal sections differed from that determined from axial and sagittal sections (P < .05). Between 2.9 and 5.4 kN of force (296-550 kg) was needed to crush a vertebra. A linear correlation between the ultimate compressive strength and T2* of all vertebrae was observed for all imaging planes and section thicknesses (P < .001, except for 10-mm sagittal images, for which P < .002). The T2* determined for the axial plane showed the best correlation with the ultimate compressive strength (r = -0.83). CONCLUSION: The correlation between T2* values and vertebral strength indicates that MR imaging may potentially be used to predict fracture risks in patients.
Assuntos
Vértebras Lombares/fisiopatologia , Imageamento por Ressonância Magnética , Animais , Força Compressiva , Feminino , Vértebras Lombares/anatomia & histologia , SuínosRESUMO
We present a filmless pediatric radiology department for the Stockholm area (1.8 million inhabitants) producing 50000 examinations per year. Seventy percent of the examinations are non scheduled, 50% are emergency cases out of office hours. The system is designed for high reliability operating with 99.7% uptime. A large number of daily conferences are held throughout the Children's Hospital at the various specialized departments, distributed through the intranet, with one pediatric radiologist attending. Instant reading is made in the majority of examinations and reports are available with images throughout the hospital including PC's at doctors rooms. The system uses conventional hardware and software with an open systems standard based approach. The system is highly appreciated by clinicians and has improved availability of radiology information.
Assuntos
Hospitais Pediátricos , Redes Neurais de Computação , Sistemas de Informação em Radiologia , Humanos , Pediatria , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Sistemas de Informação em Radiologia/instrumentação , SuéciaRESUMO
A study was carried out of 302 major amputations for vascular insufficiency in the lower limb with respect to levels of amputation, postoperative revisions, re-amputations on a higher level and postoperative mortality. This information was related to vascular disease (diabetes mellitus/arteriosclerosis) and to the experience of the surgeon. There was a high incidence of above-knee amputations both of diabetics and arteriosclerotics and the rate of complications was high for "senior" as well as "junior" surgeons. The amputations were performed during 1978 and the study has shown that there is an urgent need to lower the level of amputation without increasing the rate of complications. The study indicates that there is a need for further information about the problems involved in rehabilitation of above-knee amputees.
Assuntos
Amputação Cirúrgica/métodos , Arteriosclerose/cirurgia , Angiopatias Diabéticas/cirurgia , Perna (Membro)/irrigação sanguínea , Idoso , Amputação Cirúrgica/mortalidade , Amputação Cirúrgica/reabilitação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , ReoperaçãoRESUMO
The SBU-report no 127 "Mätning av bentäthet" [Measuring bone density] was published in 1995 and its conclusions are still valid. However, since then new treatment modalities have placed increasing demands on the diagnostic capability and performance of the apparatus used for bone densitometry. The most well-established and widely used technique for bone mineral determination is dual energy X-ray absorptiometry. Several international studies have shown that quantitative ultrasound should not be used for diagnosis or monitoring of osteoporosis. The reproducibility of one's method is important for monitoring, and the method's accuracy is important for diagnosis. Due to the limitations of the techniques and the slow turnover of the skeleton, repeated measurements are not meaningful until at least two years have passed. In order to maintain high quality in measurement results it is important to have trained personnel and to have a regular quality assurance program for the apparatus.
Assuntos
Densidade Óssea , Densitometria/métodos , Osteoporose/diagnóstico , Absorciometria de Fóton/normas , Densitometria/normas , Humanos , Osteoporose/diagnóstico por imagem , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , UltrassonografiaRESUMO
Available films of 21 cases of erroneously diagnosed Wilms' tumor in the European Wilms' material have been studied. The diagnosis has been reassessed and the reasons for agreement in 6 cases and disagreement in the remaining 15 are discussed. General diagnostic recommendations are given to help secure optimal diagnostic information.
Assuntos
Neoplasias Renais/diagnóstico por imagem , Tumor de Wilms/diagnóstico por imagem , Pré-Escolar , Erros de Diagnóstico , Feminino , Humanos , Masculino , RadiografiaRESUMO
Paediatric patients have a higher average risk of developing cancer compared with adults receiving the same dose. The longer life expectancy in children allows more time for any harmful effects of radiation to manifest, and developing organs and tissues are more sensitive to the effects of radiation. This publication aims to provide guiding principles of radiological protection for referring clinicians and clinical staff performing diagnostic imaging and interventional procedures for paediatric patients. It begins with a brief description of the basic concepts of radiological protection, followed by the general aspects of radiological protection, including principles of justification and optimisation. Guidelines and suggestions for radiological protection in specific modalities - radiography and fluoroscopy, interventional radiology, and computed tomography - are subsequently covered in depth. The report concludes with a summary and recommendations. The importance of rigorous justification of radiological procedures is emphasised for every procedure involving ionising radiation, and the use of imaging modalities that are non-ionising should always be considered. The basic aim of optimisation of radiological protection is to adjust imaging parameters and institute protective measures such that the required image is obtained with the lowest possible dose of radiation, and that net benefit is maximised to maintain sufficient quality for diagnostic interpretation. Special consideration should be given to the availability of dose reduction measures when purchasing new imaging equipment for paediatric use. One of the unique aspects of paediatric imaging is with regards to the wide range in patient size (and weight), therefore requiring special attention to optimisation and modification of equipment, technique, and imaging parameters. Examples of good radiographic and fluoroscopic technique include attention to patient positioning, field size and adequate collimation, use of protective shielding, optimisation of exposure factors, use of pulsed fluoroscopy, limiting fluoroscopy time, etc. Major paediatric interventional procedures should be performed by experienced paediatric interventional operators, and a second, specific level of training in radiological protection is desirable (in some countries, this is mandatory). For computed tomography, dose reduction should be optimised by the adjustment of scan parameters (such as mA, kVp, and pitch) according to patient weight or age, region scanned, and study indication (e.g. images with greater noise should be accepted if they are of sufficient diagnostic quality). Other strategies include restricting multiphase examination protocols, avoiding overlapping of scan regions, and only scanning the area in question. Up-to-date dose reduction technology such as tube current modulation, organ-based dose modulation, auto kV technology, and iterative reconstruction should be utilised when appropriate. It is anticipated that this publication will assist institutions in encouraging the standardisation of procedures, and that it may help increase awareness and ultimately improve practices for the benefit of patients.
Assuntos
Proteção Radiológica/métodos , Proteção Radiológica/normas , Radiologia Intervencionista/métodos , Radiologia Intervencionista/normas , Radiologia/métodos , Radiologia/normas , Adolescente , Criança , Pré-Escolar , Feminino , Fluoroscopia/métodos , Fluoroscopia/normas , Humanos , Lactente , Recém-Nascido , Cooperação Internacional , Masculino , Pediatria/métodos , Pediatria/normas , Doses de Radiação , Lesões por Radiação/prevenção & controle , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/normasRESUMO
It is well known that paediatric patients are generally at greater risk for the development of cancer per unit of radiation dose compared with adults, due both to the longer life expectancy for any harmful effects of radiation to manifest, and the fact that developing organs and tissues are more sensitive to the effects of radiation. Multiple computed tomography (CT) examinations may cumulatively involve absorbed doses to organs and tissues that can sometimes approach or exceed the levels known from epidemiological studies to significantly increase the probability of cancer development. Radiation protection strategies include rigorous justification of CT examinations and the use of imaging techniques that are non-ionising, followed by optimisation of radiation dose exposure (according to the 'as low as reasonably achievable' principle). Special consideration should be given to the availability of dose reduction technology when acquiring CT scanners. Dose reduction should be optimised by adjustment of scan parameters (such as mAs, kVp, and pitch) according to patient weight or age, region scanned, and study indication (e.g. images with greater noise should be accepted if they are of sufficient diagnostic quality). Other strategies include restricting multiphase examination protocols, avoiding overlapping of scan regions, and only scanning the area in question. Newer technologies such as tube current modulation, organ-based dose modulation, and iterative reconstruction should be used when appropriate. Attention should also be paid to optimising study quality (e.g. by image post-processing to facilitate radiological diagnoses and interpretation). Finally, improving awareness through education and advocacy, and further research in paediatric radiological protection are important to help reduce patient dose.