Abstract: Objective To explore the feasibility of reducing radiation dose in argon-helium cryotherapy under multi-slice spiral CT guidance using low-dose scanning program. Methods Fifty-two patients with lung tumor, treated with argon-helium cryoprotective surgery, were divided into low dose group (group A) and conventional group (group B).The group A patients (22 patients) and group B (30 patients) were treated respectively by low dose scanning program with 120 kV, ATCM (15-60 mA) and 120 kV, ATCM (50-600 mA). The image quality (argon helium cryoides, the frozen ice hockey), radiation dose CTDI, image noise were observed and evaluated. Results The radiation dose index between two groups was significant difference (P<0.05). Compared with group B, the radiation dose index in group A was decreased by 80.90%. The difference of CT value and image noise between two groups has not significant difference (P > 0.05). There difference in the image quality score between group A and group B have statistically significant (P=0.020).The other score about image evaluating was not significant difference between two group (P > 0.05). Conclusion In the lung cancer under CT guidance of argon-helium cryotherapy, the low-dose scanning program not only reduced the radiation dose of patients effectively but also ensure the accuracy, safety of the treatment.

Key words: low-dose, lung cancer, computed tomography, argon-helium cryotherapy, image quality