ABSTRACT
Objective To investigate the entrance surface dose to the examined patients in radiography using digital and screen-film system in hospitals at different levels in 15 provinces and municipalities in China,in order to provide data for developing diagnostic reference level of radiography suitable for our national physical characteristics.Methods According to the requirements of the Technical Study on Medical Radiation Hazard Assessment and Control,the examined patients aged 20-70 years were selected,with body weight ranging from 55 to 80 kg for male and 50 to 70 kg for female.TLDs were used to measure the entrance surface dose to adult patients in radiography.No less than 10 examined patients were required at each body position,with examined locations including head (PA,LAT),chest (PA,LAT),abdomen (AP),pelvis (AP),lumbar (AP,LAT),and thoracic vertebra (AP,LAT).Results A total of 19 975 individuals undergoing radiography and 1 813 radiographic equipment of different types including screen-film radiography,computed radiography (CR) and digital radiography (DR),were investigated in 342 hospitals in 15 provinces and municipalities throughout the country.For these three types of equipment,the average entrance surface dose to the examined were 1.75,1.9,and 1.15 mGy in head (PA),1.69,1.46and 1.03 mGy in head (LAT),0.75,0.65 and 0.36 mGy in chest (PA),1.81,1.26 and 0.88 mGy in chest (LAT),4.37,3.77 and 2.15 mGy in abdomen (AP),3.73,3.56 and 2.75 mGy in pelvis (AP),5.49,5.84 and 4.17 mGy in lumbar (AP),12.01,9.37 and 6.82 mGy in lumbar (LAT),4.53,3.65 and 2.49 mGy in thoracic vertebra (AP),and 6.91,6.43 and 4.15 Gy in thoracic vertebra (LAT).Conclusions Entrance surface dose caused by radiography examination varies dependent on different exposure locations.Entrance surface doses caused by digital radiography are all lower than by screen-film radiography;those caused by digital radiography are lower than by computed radiography,except for thoracic vertebra (AP).In all examinations,no difference of statistical significance is found between CR and screen-film radiography in entrance surface dose.
ABSTRACT
According to the comparison of CR and DR in such aspects as principle analysis,main parameters,software operation capability and development prospects,along with our experience,it is concluded that CR is now fit for the middle and small hospitals as an expedient intergrading digital image equipment,while for the hospitals with workload of over 100 persons per day,DR should be the primary digital image equipment and CR should work as auxililiary digital image equipment.
ABSTRACT
Objective To investgate the CR signs of mammary cancer, to raise the cognitions of CR signs of mammary cancer. Methods 56 CR imaging of mammary cancer with confirmed by patholog and intact clinical data were analyzed retrospectively. Results The direct signs of mammary cancer were mass, cluster or needle poin calcification and hair pricking. The indirect signs were abnormal macula structure, local Thickening of skin, crater nipple, thick vessal imaging and choana sign. Conclusion The CR signs of mammary cancer were diversify, the characteristic signs was be seen in many patients. The direct or indirect signs of mammary cancer should be analysed carefully in clinical application for rising rate of diagnosis.
ABSTRACT
Objective To compare the dose exposure and the dose equivalent of computed radiography and common radiography.Methods The dose of exposure and the dose equivalent of three image carrier including average speed intensifying screen-film, green screen-film and IP plate were detected and compared using tools such as thermoluminescence determinator and line-pair card.Results In 2.0 L.P/mm, the dose exposure of IP plate was 5% of average speed intensifying screen-film and 33% of green screen-film,the mean dose equivalent of IP plate was 3% of average speed intensifying screen-film and 35% of green screen-film. In 4.0 L.P/mm, the dose exposure of IP plate was 200% of average speed intensifying screen-film and 950% of green screen-film,the mean dose equivalent of IP plate was 180% of average speed intensifying screen-film and 1110% of green screen-film. In 2.5～3.2 L.P/mm, the dose exposure of IP plate was 50%～75% of average speed intensifying screen-film and 220%～290% of green screen-film,the mean dose equivalent of IP plate was 37%～66% of midvelocity screen-film and 190%～270% of green screen-film.Conclusion In 2.5～3.2 L.P/mm, both dose exposure and mean dose equivalent of IP plate are lower than that of average speed intensifying screen-film about 1/2～3/4 times of mAs and 1/3～2/3 times of mSv; but higher than that of green screen-film about 2～3 times of mAs, 2～3 times of mSv.The high quality images of CR can be obtained as projection in this extent.
ABSTRACT
Objective To investigate the application of computed radiography(CR) in X-ray projection of whole lower limbs.Methods The radiography in the patient with bilateral knee-malformation was performed using 500 mA X-ray apparatus and several imaging plates(IP) jointed together,then the images including whole both sides of lower limbs were obtained by post-proccesing technique.Results The images not only could show the whole lower limbs on a single film,but be intact.The images also could be used for measuring the length of leg,the angle between the axises of the thigh and the magnifying really.Conclusion The image of whole bilateral lower limbs with a good quality and unity can be acquired using CR and post-processing technique appropriately.
ABSTRACT
Objective To investigate the applied value of computed radiography(CR) system in intravenous pyelography in children.Methods Intravenous pyelography were carried out by CR and traditional intensifying screen/film in 45 children respectively.The diagnostic specificity between CR and traditional intensifying screen/film was compared.Results Urinary system in children could be displayed well by CR,the quality of CR films was ensured.The diagnostic corresponding rate was 86.7% and 59.1% by CR and traditional intensifying screen/film respectively.Conclusion CR is of significance value in diagnosis of urologic diseases in children.
ABSTRACT
Objective To study the application values in chest bedside photograph of newborn by CR.Methods 210 CR images of newborn chest bedside photograph were analyzed retrospectively and evaluated.Class A is 201 leaves,the A rate is 95.7%;Class B is 9 leaves,the B rate is 4.3%;Class waste is 0,the waste rate is 0.Results The application value can be improved by appearing digitalization imaging and entering PACS system.Conclusion In spite of the characteristic in the faster diagnosis speed,the lower exposure of X-ray,the higher quality image and succeed rate,it can be given guides for clinic image diagnose.
ABSTRACT
Objective To study the adjustment principle and optimizing methods of the image processing parameters of Computed Radiography(CR), including the image density, contrast degree, tissue equalization, spatial frequency, LUT curve,etc. Methods Konica REGIUS MODEL170 CR was applied to adjust various image processing parameters on its CS-1 console. Results Images of all parts of body could be optimized and improved. Conclusion High-quality medical images are available only if the adjustment methods of image processing parameters are completely comprehended and reasonably applied.