An ultra-low-dose protocol for computed tomography-guided lung radiofrequency ablations

Abstract

Purpose To evaluate safetey and efficacy of an ultra low dose (ULD) protocol implementation during lung radiofrequency ablations. Methods All patients who underwent a lung RFA were consecutively and retrospectively included between November 2017 and January 2021. 30 patiens were treated with a historical standard protocol (SP), 31 with an ULD protocol. Patient characteristics, dose indicators, technical efficacy (minimal margin MM, recurrence during the follow up) and complications (pneumothorax, alveolar hemorrhage, hemoptysis) were recorded. Results 61 patients were included (median age, 65 [54. 73], 33 women). There was no significant difference in the characteristics of the patients according to the type of protocol, except for the type of anesthesia. Even if the number of helical acquisitions had not significantly changed, all the dose indicators significantly decreased by 1.5-fold to 3-fold. The median dose-length-product and effective dose were respectively 465mGy.cm [315; 554] and 6.5mSv [4.4; 7.8] in the SP group versus 178 mGy.cm [154; 267] and 2.5mSv [2.2; 3.7] in the ULD group, (p<.001). The ULD group presented a lower intra-operator variability and a better inter-operator alignment. The MM were not significantly different in the 2 groups (4.6mm versus 5mm, p=.16). One local recurrence was observed in each group, at 8 months for the SP and at one year for the ULD group (p=1). No significant difference was found in the complications rates. Conclusion Implmenting an ultra-low dose protocol during lung RFA may allow with the same efficacy, a reduction of dose indicators, intra- and inter-operator alignments, without increasing complications rates.