Abstract: ［Abstract］Objective〖HTSS〗To investigate the accuracy and quality control of 1〖DK〗∶1 DR chest radiography in whole-body radiotherapy.
Methods〖HTSS〗The 47 patients who met the inclusion criteria were selected for 1〖DK〗∶1 DR chest radiography. According to the chest body thickness(front and back diameter), the patients were divided into A, B and C 3 groups, 17 in group A(body thickness H1≤ 20 cm), 15 in group B(body thickness H2 >20-24 cm), and 15 in group C(body thickness H3 >24 cm). According to the shape and size of lung field in 1〖DK〗∶1 DR chest radiograph, a lung block was made to shield the lung effectively in whole body radiotherapy. Set the left and right diameter of the patient′s chest as S1, and the distance between two chest walls of the chest image as S2. The printing proportion of photos before quality control was 100%, after quality control, the printing proportion of photos set according to the chest thickness range of patients was 93%, 91% and 89%, respectively. S1 and S2 of patients before and after quality control were compared. At the same time, the changes of S2 in the same patient under different respiratory states were compared.
Results〖HTSS〗Before quality control, the distance between two sides of chest wall(S2) in group A, B and C3 was significantly greater than that in group S1(P＜0.05). After quality control, there was no significant difference between left and right chest diameter(S1) and the distance between two sides of chest wall(S2) in group A, B and C(P＞0.05). The deep breath holding state S2 of the same patient was significantly higher than that of the calm breath holding state S2(P＜0.05).
Conclusion〖HTSS〗After control, according to the thickness of the patient′s chest, the printing proportion of the chest image was determined to be 93%, 91% and 89%, respectively. The DR chest film with the same lung field and lung size on the DR chest film, 1〖DK〗∶1 DR chest film, can be obtained. The lung lead block made according to it can shield the lung accurately in the whole body radiotherapy, which is worth popularizing and applying.

Key words: whole-body irradiation, 1〖DK〗∶1 DR chest radiograph, lung blockage lead