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1、Apr20 1 0，Volume 4，No4(Serial No29) Journal of Materials Science and Engineering，ISSN 1 9348959，USA N Study on Image Quality of Computed Radiography Gede Bayu Suparta，Nugroho Waskito and Lestari Sri Department ofPhysics，Faculty ofMathematics and Natural Sciences，Gadjah Mada University，tbg),akarta 55
2、281，Indonesia Received：January 13，2010Accepted：January 222010Published：April 25，2010 Abstract：This study examined the image quailty on Computed Radiography(CR)in conjunction with the proper radiation dose as indicated based on the set-up on the anodecathode voltage(V)and filament current(i)During th
3、is studya set of radiographic images of step wedge for various combinations of V and i was developedThe results showed that good image quality may be achieved by considering the effective V and i set upIncreasing V had a better effect to the image quality rather than increasing iThe Xray power setuD
4、 of 2540 kW with voltage 50 kV80 kV and current of 50 mA may be chosen depends on the targeted aluminum thickness equivalent to obtain good image quality at the acceptable low radiation dose Optimization setup based on aluminum(AI)thickness equivalent may lead to significant reduction on the radiati
5、on dose and power consumption Key words：Computed radiograph) radiation doseXrayradiology 1Introduction Computed Radiography(CR)is a new trend for radiography technique1】CR is very impressive due tO its ability in providing high resolution digital images， quantitative measurement，quick image producti
6、on and consistent performance on image developmentIt is also able to be processed and manipulated for better clarity2】CR has been applied on medical imaging， specifically on diagnostic radiography3The use of phosphor storage for developing temporary images has great benefit since the phosphor storag
7、e can be used many timesAlthough CR sounds promising，radiation safety still becomes a great concern4-8 In Indonesia，although CR has been accepted，the standard operation procedure for CR is still based on film radiography【9，1 0，especially in conjunction with the set-up on the anode-cathode voltage( a
8、nd the filament current i of the X-ray tubeV(in kV)and i(in mA)set up directly contributes to the X-ray radiation intensity that impinge the obj ect，so that the absorbed Xray energy in the objectHence，that Xray radiation Corresponding author：Gede Bayu Suparla(1 965-)，male， associate professor，resear
9、ch fields：physicsphysics of imagingEmail：gbsupartaugmacid intensity( correlates to the absorbed energy dose(rad) or the equivalent dose(rem)in the object1 1141The relation between intensity l to the V and i setup can be described by Equation(1)【1 5 oc (1) Equation(1)shows that intensity I increases
10、by power of(20士01)when Vincreases，while it changes linearly when i increasesSince increasing V leads to increasing the mean energy，the penetration capability of the Xray also increasesHence the radiation dose also increasesConsidering the radiation safety，the combination between V and f has to be de
11、termined in accordance to the image quality being resultedThe V mainly effects to the power of penetration and so it is responsible to the image contrastThe i mainly effects to the image brightnessThe image sharpness mainly defined by the object position relative to the X-ray source and film screen(
12、CR casseue) This paper reported our study in a hospital in Indonesia related with the examination of the CR image quality based on the V and i setupThe aim of this research was to explore the possibility on reducing radiation dose to the patient through the V and i set-up in the CR implementation 2E
13、xperiment Study on Image Quality of Computed Radiography Experiment was carried out at one hospital closed to the Gadjah Mada UniversityThe CR facility comprised of an X-ray facility for providing X-ray radiation tracer to the object，a phosphor storage casseRe(PSC)to store a temporary image ofthe ob
14、ject， and a CR panel for converting the image on the PSC to a digital image of the objectThe CR images were taken and developed by an authorized operator in that hospita1The radiography process has followed the standard procedure that is regularly conducted by the radiographer The test was carried o
15、ut for a step wedge made of aluminum as the object targetIt is about 1 40 mm long and 40 mm width and it has 1 1 stepsThere was about 3 mm thick difference between stepsOn the radiography session，the PSC were laid on the object table，while the stepwedge was laid on the PSCThe object was set about 1
16、00 cm to the focal spot of Xray tubeSome images were taken for some V and i set-upsThe same PSC was used，hence the position of the PSC on the table and the position ofthe object on the PSC were set at about the same positions for all V and I setupsThe way the CR panel reads the PSC such that the orientations and the position of the casseRe were about the same The anode-cathode voltage V varied by 50 kV，6
