흉부 디지털토모영상의 기본모드 및 부가여과사용 시 환자선량과 화질비교 Digital Tomosynthesis Imaging of the Chest : Comparison of Patient Exposure Dose and Image Quality between Default Setting and Use Additional Filter원문보기
흉부 디지털토모장치는 가장 발달한 촬영방법중의 하나이지만 일반 흉부촬영방법에 비해 환자의 피폭선량이 높다는 단점이 있다. 이런 이유 때문에 본 연구는 흉부 디지털토모영상에서 부가여과를 사용하여 환자선량을 저감시키는 방법을 검토하여 보았으며, 화질의 변화도 실험하였다. 그 결과 부가여과가 없는 장치의 기본상태에서 피부입사선량, 면적선량, 실효선량은 1.95 mGy, 17.66 $dGycm^2$, 0.133 mSv로, 부가여과사용시는 0.312 mGy, 2.27 $dGy.cm^2$, 0.052 mSv로 나타나 선량이 각 각 66.2%, 73.6%, 57.4%로 감소하였다. 화질에서 병소의 검출율은 중심부 미소병소 검출율(p < .001)을 제외한 나머지 주변부, 중심부병변 및 주변부 미소병소에서는 두 방법에서 큰 차이를 보이지 않았으며, 환자의 선량감소에는 큰 효과를 볼 수 있었다.
흉부 디지털토모장치는 가장 발달한 촬영방법중의 하나이지만 일반 흉부촬영방법에 비해 환자의 피폭선량이 높다는 단점이 있다. 이런 이유 때문에 본 연구는 흉부 디지털토모영상에서 부가여과를 사용하여 환자선량을 저감시키는 방법을 검토하여 보았으며, 화질의 변화도 실험하였다. 그 결과 부가여과가 없는 장치의 기본상태에서 피부입사선량, 면적선량, 실효선량은 1.95 mGy, 17.66 $dGycm^2$, 0.133 mSv로, 부가여과사용시는 0.312 mGy, 2.27 $dGy.cm^2$, 0.052 mSv로 나타나 선량이 각 각 66.2%, 73.6%, 57.4%로 감소하였다. 화질에서 병소의 검출율은 중심부 미소병소 검출율(p < .001)을 제외한 나머지 주변부, 중심부병변 및 주변부 미소병소에서는 두 방법에서 큰 차이를 보이지 않았으며, 환자의 선량감소에는 큰 효과를 볼 수 있었다.
Chest digital tomosynthesis was the most advanced digital radiography technology, but it was higher patient dose than conventional chest radiography. Thus we tried to reduce a patient dose of chest digital tomosynthesis and evaluated its image quality. Result shows that radiation dose such as ESD, D...
Chest digital tomosynthesis was the most advanced digital radiography technology, but it was higher patient dose than conventional chest radiography. Thus we tried to reduce a patient dose of chest digital tomosynthesis and evaluated its image quality. Result shows that radiation dose such as ESD, DAP and ED were 1.95 mGy, 17.66 $dGycm^2$ and 0.133 mSv respectively in default setting and 0.312 mGy, 2.27 $dGy.cm^2$ and 0.052 mSv in use additional filter, respectively. Doses were decrease 66.2%, 73.6% and 57.4% in ESD, DAP and ED, respectively. At the image quality assessment, overall sensitivities of use additional filter for nodule detection were not inferior to default mode for peripheral, central and peripheral micro nodules. However, sensitivity of low dose mode was significantly inferior to the default for central micro-nodules(p < .001).
Chest digital tomosynthesis was the most advanced digital radiography technology, but it was higher patient dose than conventional chest radiography. Thus we tried to reduce a patient dose of chest digital tomosynthesis and evaluated its image quality. Result shows that radiation dose such as ESD, DAP and ED were 1.95 mGy, 17.66 $dGycm^2$ and 0.133 mSv respectively in default setting and 0.312 mGy, 2.27 $dGy.cm^2$ and 0.052 mSv in use additional filter, respectively. Doses were decrease 66.2%, 73.6% and 57.4% in ESD, DAP and ED, respectively. At the image quality assessment, overall sensitivities of use additional filter for nodule detection were not inferior to default mode for peripheral, central and peripheral micro nodules. However, sensitivity of low dose mode was significantly inferior to the default for central micro-nodules(p < .001).
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제안 방법
Also, inserted 3 sets of artificial nodules into the inside of phantom and attached 20 artificial nodules randomly on the surface(lower lung, vertebral region) of model which looks like diaphragm to support the model such as original lung to insert into phantom.
Thus, the purpose of this study was to find dose reduction setting to reduce the patient dose in DTS examination and compare the image quality between the default setting.
To evaluate the image quality, take out the lung model and diaphragm inserted into lung/chest Phantom and made and fixed 3 set of artificial nodules phantom inside.
Tube voltages, copper filter thickness, and dose ratio were changed to the followings and exposed, and recorded ESD, DAP displayed on the equipment from each combination.
We checked the significance in the numbers of nodule and sensitivities detected under the four conditions combined differently by size and region like central micro nodules, peripheral micro nodules, central nodules and peripheral nodules using ANOVA analysis in LD setting and default setting. (SPSS 1.
We cut the Styrofoam fit to the internal size of phantom and attached randomly total 20 grains of soaked adlay, red-bean, millet and un-soaked millet, 5 grains each, on one of Styrofoam and made 3 sets of artificial nodules.
성능/효과
Also, in case of dose ratio 1:5, the values of DAP and ESD at 120 kVp were decreased by 65.42% and 58.7% and at 100 kVp and 80 kVp, the value of DAP was decreased by 55.58% and 46.18%, the value of ESD were by 53.73% and 46.38% respectively.
Therefore, in this study, we have tried to find out the method to reduce the patient dose in DTS to that of chest PA. As a result, average DAP and ESD at three tube voltages were reduced by 49.7% and 48.3% respectively at dose ration 1:5 compared to doses ration 1:10 and when Cu filter was used (dose ratio was fixed at 1:5), DAP and ESD were decreased by 49.7% and 52.9% each.
Finally, looking at the dose change according to the change of kVp when the Cu filer was used or not (dose ratio fixed at 1:5) at tube voltage from 120 kVp to 100 kVp, the value of DAP was decreased by 23.57% and 40.51% and the value of ESD was decreased by 18.4% and 27.1% respectively.
Second, Compared by the use of Cu filter, the measured values of DAP and ESD at 120 kVp in dose rate 1:10 were decreased 72.99% and 69.08% respectively and at 100 kVp and 80 kVp, the value of DAP was decreased by 56.75% and 48.87%, the value of ESD was decreased 53.6% and 42,52% respectively.
The conclusion of this study could reduce dose of chest DTS comparable to the conventional chest radiograph. This low dose DTS was comparable to the DTS with default dose setting for detecting lung nodules bigger than 4 mm in diameter
We have tested setting dose ratio as 1:10(default) and 1:5. When the test was performed with 1:5 ratio at 120 kVp, the values of DAD and ESD were decreased by 51.36% and 52.82% respectively compared with 1:10 ratio and at 100 kVp and 80 kVp, the value of DAP was decreased by 52.06% and 51.49% respectively and the value of ESD was decreased by 46.4% and 45.67% respectively.
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