Contrast Study of chest Dr double energy subtraction and DR chest X-ray and chest CT absorption dose

Comparison of Dr dual-energy subtraction and DR chest X-ray and CT absorption dose in the chest; Research Institute of medical imaging, Nanjing General Hospital of Nanjing Military Region (210002) Wang Jun digital X-ray photography (DR) chest double-energy subtraction plays a role in the diagnosis of pneumothorax, pulmonary nodules and calcification in nodules, rib fracture, coronary artery calcification, etc. [1-5]. However, it brings medical benefits to the clinic, but also has a negative impact due to the increased X-ray absorption dose of the person being examined. Therefore, from the perspective of X-ray absorption dose, this paper discusses the Dual Energy Subtraction (DES), Dr high kilovolt X-ray photography, Dr sub-high kilovolt X-ray photography, as well as the differences between conventional chest CT scans and low-dose Chest CT scans examined by X-ray absorption dose, chest imaging procedures are clarified from the perspective of dose. Materials and MethodsThis study uses Ge DR (revolution XQ/I, amorphous silicon detector) for chest dual-energy subtraction, high kilovolt X-ray photography, sub-kilovolt X-ray photography, and conventional chest CT (Siemens SOMATOM spirit) SOMATOM emotion scan and low-dose Chest CT scan were performed to randomly detect 72 patients with absorbed dose and perform comparative analysis. Both X-ray photography and CT examination, the subjects were examined with deep breath-taking screen exposure, CT scan using a horizontal position, X-ray examination using a standing position, focal-piece distance of 180. Place the recorder in the upper right shoulder and X-ray exposure area of the subject. Measuring Instrument: FJ-427A thermal release light measuring instrument, relative sensitivity: 2.23 ~ 2.25. Photography conditions: DR chest dual-energy subtraction respectively uses a button within 320mA ms for 140kv, 500mA, 60kv, 1st Automatic Exposure to 320mA groups, and 110kv, 60 kv, 500mA were automatically exposed to 2nd groups, and Kv ~ 3rd kV groups are scanned. The Automatic Exposure of DR chest was set to 200mA with 140kv and 4th, and the automatic exposure of DR chest was set to 200mA with 110kv and 5th. Multi-layer spiral CT was used for low-dose chest scan with 6th groups of 110kv. Statistical analysis: SPSS 10.0 software was used for relevant statistical analysis to detect the comparison of multiple groups of absorbed dose using the single-factor variance analysis method. The overall comparison adopted the Welch approximate variance analysis, and the Levene statistics were calculated, the differences between two groups were statistically significant. LSD or tamhane's T2 tests were used to compare the differences between the two groups. P <0.05 was statistically significant. ResultStatistical Analysis of the random absorbed dose of all tests using the statistical software SPSS 10.0 is shown in Table 3-4 and figure 3-9. From the mean value () ± standard deviation (s) of each group, the stochastic dose caused by different chest imaging methods is roughly divided into three levels: 4th, 5th, 6th, and 0.1274 groups with the lowest random dose absorption (= 0.1699, 0.1412, 1st), and 2nd and groups with moderate dose, the 3rd group is the highest (= 0.8372 ). In general, the approximate variance of Welch is analyzed as follows: F = 22.290, P = 0.000, indicating that there is a significant difference in total. Result of variance Homogeneity test. The Levene statistic is 6.693, and the corresponding P value is 0.000 <A = 0.05, indicating that the overall variance is not consistent. For more information about the comparison using the tamhane's T2 test, see Table 3-4 and figure 3-9.

 

DiscussionFor a long time, chest x-ray photography has been favored by clinicians and those who have been examined for good image quality, and has become an indispensable routine examination in clinical evidence-based medicine. With the wide application of digital radiography (DR) in medical imaging technology and the increasing popularity of humanistic concepts, the recipient's X-ray dose has been mentioned on the agenda. In the end, the best diagnostic effect is achieved by using the lowest dose of X-ray absorption, which is the direction that medical imaging technicians need to work hard. 1. Dr dual-energy subtraction and the comparison of the dose randomly absorbed by X-ray of the examined person. With the continuous update of DR, it has been widely used in chest X-ray photography, its powerful post-processing function, appropriate edge enhancement at high spatial frequencies, can compensate for space resolution restrictions due to reduced Detector Pixel sizes to improve diagnostic performance [6]. In addition, it has a wide range of dynamic exposure, significantly improving the image success rate and image quality, while significantly reducing the X-ray absorption dose of the subject. What's even more valuable is that Dr has made great strides with computer development [7]. For example, Dual Energy Subtraction is one of them. Dr dual-energy Subtraction is a high-energy image and a low-energy image obtained after two exposures of high KV and low KV within ms with one button, because the bones and soft tissue signal strength in these two images are different, we can selectively remove the bone and soft tissue information from the images by means of weighted subtraction, the result is that the signal consistent with the skeleton is eliminated to obtain the soft tissue image, or the signal consistent with the soft tissue is eliminated to obtain the image of the bone tissue. Three images of the chest are obtained: standard images, bone tissue images, and soft tissue images after "separated bone and meat" (see Figure 3-10 ). In any case, one of the conditions required for obtaining high-quality subtraction images is that the X-ray energy difference between two exposures is large [8]. We use 320mA groups of 500mA kV, 1st, 60kv, and automatic exposures, 320mA, 500mA, 60kv, and 2nd were used for automatic exposure. groups were used to measure the randomly absorbed chest dose of the subjects. From the results of this study, we can see that the two groups of Dr dual-energy subtraction (between 1st and 2nd), P = 1.000, it indicates that there was no significant statistically significant difference in the random absorption dose of the subjects. Therefore, from the perspective of dose, it is necessary to increase the energy difference between two X-ray exposures to achieve better image quality. 2. Comparison of Dr dual-energy subtraction and CT random absorption dose is well known. the random absorption dose of CT Scan subjects depends on the thickness, density, and number of atoms of the subjects, it is also related to the scanning layer and number of layers. Although most of the current multi-row detector CT ball tubes are installed with "dose adjustment", its role is to automatically track and adjust the X-ray dose of CT ball tubes during the scanning process, the objective is to minimize the effective X-ray dose without affecting the diagnostic quality. The working principle is that during scanning, the dose adjustment device adjusts the CT ball tube in real time based on the measured degree of X-ray attenuation in different locations of the inspected tissue, allow the ball tube to output X-ray dose as needed during scanning. Low-dose scanning is used for low-attenuation X-ray tissue, and high-dose scanning is used for high-attenuation tissue. The exposure dose can be adjusted as needed. During selection, chest scan can reduce the effective dose by about 30% ~ 40%, meeting the needs of low-dose scans and infant CT examination [8]. However, during CT scanning, After lesions are often found, especially when considering the possibility of lung cancer, the subjects still need to perform thin-layer CT scans, or even multi-phase enhanced scans. In addition, with the increase of CT scan speed, the use of CT scan to diagnose the disease "spread the network" phenomenon increases, which further increases the randomly absorbed dose of the examined. In this study, the random dose absorbed by routine CT scans was the highest among all groups, with an average of 0.8372 (see Table 3-4, Figure 3-9). From the statistical analysis, there was a significant statistical difference with each group, P <0.05. However, once a low-dose Chest CT scan is used, the absorbed dose of the subjects is greatly reduced, with a significant statistical difference between 0.1412 and each group, P <0.05. The random dose absorbed by Dr dual-energy subtraction included between conventional chest CT scan and low dose Chest CT scan. Therefore, when Dr high kilovolt photography is suspected of a fracture, or a small nodules are found, you can consider replacing Dr dual-energy subtraction as needed [1]. However, the effect of dual-energy subtraction cannot be exaggerated. From the perspective of dose analysis, the X-ray absorption dose of dual-energy subtraction was higher than that of low-dose Chest CT scans. Therefore, the indications for extended low-dose Chest CT scans can be properly considered, especially when only plain scans are needed. In which cases, target scans can be performed, and direct thin-layer scans are only required for lesions; in which cases, only one operation specification needs to be directly enhanced to greatly reduce the random dose absorbed by CT subjects; from the table 3-4, we can see that the dose of routine CT absorption is higher than that of S in other groups, while the low dose of chest CT scan is lower in each group, this, in turn, proves the necessity of using a low-dose CT scan for the above reasons. 3. Comparison between Dr dual-energy subtraction and Dr high kilovolt X-ray photography at random dose absorption. Dr is based on cesium iodide and CEI and amorphous silicon, a-Si) the sensitive matrix flat-panel X-ray detector provides high spatial resolution, high contrast resolution, and digital X-ray photos with the potential to reduce X-ray dose [9, 10]. It consists of an X-ray ball tube, a generator, and a large-area amorphous silicon flat detector. The detector is composed of a CEI flashing device and an array of amorphous silicon PHOTODIODES mounted on a glass chip. The CEI flashing device coated with e-grams converts X-rays to visible light. The flashing device has a fine structure like a needle and is placed on a amorphous silicon diode array. The amorphous silicon diode array converts light into a charge, which is read by electrons and converted into a 14bit signal. This digital detector has a high quantum detection efficiency (DQE). The obtained image quality and the display capability of the organizational structure are superior, the location and exposure conditions of the person being examined can be quickly reported to the X-ray photography technician [11]. In addition, the application of high kilovolt X-ray photography technology and the application of tissue balancing improve the visibility of the background images of the ribs and the heart, and enrich the image layers of chest X-ray photography. Dr dual-energy subtraction has two X-ray exposures, and the X-ray dose increases accordingly. According to the results of this study, dr dual-energy subtraction chest X-ray photography the recipient's random X-ray absorption dose is higher than Dr high kilovolt chest photography (see Table 3-4, Figure 3-9 ), 1st groups and 2nd groups were significantly higher than 4th groups and 5th groups. Therefore, from the perspective of dose, Dr dual-energy subtraction can only be used as an auxiliary method for chest examination, which is a supplement to Dr high kilovolt chest X-ray photography. Only in special circumstances, if a rib fracture may be considered [2], can the examination be the first choice. In other words, Dr high-kilovolt chest X-ray photography is still one of the conventional examination methods, Dr double energy subtraction technology cannot be listed as the conventional use of chest X-ray examination. 4. The rational use of low dose can be seen from table 3-4: 4th groups and 5th groups of High-kilovolt chest X-ray photography and 6th groups of low-dose Chest CT scans, it is the lowest among all groups, which may be associated with Dr high-kilovolt 1-time automatic exposure and low-dose CT scanning software; chest double-energy subtraction in the middle, it was automatically exposed twice on X-ray. Therefore, compared with Dr high-kilovolt chest X-ray photography, the absorption dose and fluctuation range increased, while the absorption dose of routine chest CT scans was the highest among those examined, its Influencing Factors depend not only on the automatic adjustment function of the X-ray dose, but also on the thin-layer scan and multiple checks between the plain scan and enhancement. Therefore, these factors are the basis for increasing the X-ray absorption dose and fluctuation range. Therefore, the chest imaging examination plays an important role in the diagnosis of chest diseases, while ensuring the image quality, how to reduce the random absorption dose of the examinee; or, comprehensive advantages and disadvantages, scientific selection of imaging methods, and appropriate application. In any case, the protection for the imaging of the person being examined is not only the responsibility of the Medical Imaging Technician, but also the obligation of all medical staff to achieve reasonable use of low dose (as low as reasonably achievable, ALARA) [12]. Therefore, according to this study, the minimum dose of imaging methods should be used for various imaging examinations according to their respective indications. For example, the double energy Subtraction Technique is relatively high because of its relatively high X-ray absorption dose, appropriate applications should be used as a supplement to conventional DR chest high kilovolt photography, while low-dose Chest CT scans can expand their indications due to their relatively low X-ray absorption dose, in addition, the objective scan and direct enhancement should be taken into consideration based on the condition to minimize the X-ray absorption dose. Conclusion from the perspective of dose, there is a significant difference between Dr dual-energy subtraction and Dr high kilovolt chest X-ray photography, as well as the randomly absorbed dose between CT and chest scans, the random absorption dose of Dr dual-energy subtraction was between Dr high kilovolt chest X-ray photography, low dose Chest CT scan and conventional CT chest scan. Therefore, it is recommended that Dr dual-energy subtraction be used as a supplement to Dr high-kilovolt chest X-ray photography when the condition permits, however, it cannot be exaggerated only from the perspective of dose. The Dr double energy subtraction technique should be used appropriately, especially the chest CT scan with low dose, to reduce the random dose absorbed by the examinee as a whole.

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