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目的比较数字化乳腺摄影系统与屏片乳腺摄影系统(Screen Film Mammography,SFM)在影像质量与授予剂量方面的差异,并通过对各种乳腺摄影方式的系统研究,探索其各自的影像质量与剂量关系,以及各系统之间影像质量与剂量的比较关系。方法选取屏片摄影系统、数字摄影(Digital radiography,DR)系统和计算机X射线乳腺摄影(Computed Radiography,CR)系统,利用乳腺摄影模体(CDMAM)获取不同摄影系统的影像,并根据所用摄影条件确定所获取影像所接受的平均腺体剂量(Average Glandular Dose,AGD),采用实验研究与统计分析相结合,分别对影像质量随AGD变化的趋势进行分析,并对相同或相近AGD时不同类型成像设备的影像质量进行比较。结果影像质量随AGD变化的趋势:在设定的剂量范围内,随剂量增加,所有数字摄影系统的影像质量都有所改善,但改善程度不显著;对SFM而言,随剂量增加,影像质量首先有所改善,随后随剂量继续增加,影像质量有所降低,具有明显的最优剂量点,对应AGD在2.4 mGy左右。结论所有的乳腺摄影系统,在常用曝光条件下,随着剂量的增加,影像质量先有所提高,然后随着剂量继续增加,影像质量变差或趋于平稳,其中SFM系统存在较为明显的剂量拐点,即该剂量点影像质量最好。
Objective To compare the differences in image quality and dose between digital mammography system and screen film Mammography (SFM). Through the systematic study of various mammographic methods, explore their relationship between image quality and dose , As well as the comparison of image quality and dose between systems. Methods The radiography system, digital radiography (DR) system and computerized radiography (Computed Radiography) system were selected to obtain the images of different photographic systems by using the mammography phantom (CDMAM). According to the photographic conditions The mean Glandular Dose (AGD) accepted by the obtained images was determined. The experimental study and statistical analysis were combined to analyze the trend of the image quality changes with the AGD. The different types of images at the same or similar AGD The image quality of the device is compared. Results The trend of image quality with AGD was as follows: within the set dose range, the image quality of all digital photography systems improved with dose increase, but the degree of improvement was not significant; for SFM, with the increase of dose, image quality The first improvement, then with the dose continued to increase, the image quality has decreased, with the most obvious dose point, corresponding to AGD at 2.4 mGy or so. Conclusion All the mammography systems have improved the image quality with the increase of the dose under the common exposure conditions. Then the image quality deteriorates or tends to be stable as the dose continues to increase, in which the SFM system has a more obvious dose Inflection point, that the dose point image quality is the best.