Application value of liquid fiducial marker in image-guided radiotherapy

This study was conducted to evaluate the application value of a degradable liquid fiducial marker (LFM) in image-guided radiotherapy. In vitro experiment: using a solid fiducial marker (SFM) as a reference, the visibility, artifact, and optimal injection volume of an LFM under different cone beam CT tube voltage conditions were evaluated. In vivo experiment: using the SFM as a reference, the stability and degradation status of the LFM in nude mice were evaluated. Nude mice implanted with tumor cells were randomly divided into four groups: single fraction radiotherapy group (16 Gy/fraction) without LFM injection, single fraction radiotherapy group (16 Gy/fraction) with LFM injection, 2 fractions radiotherapy group (8 Gy/fraction) with LFM injection, and 4 fractions radiotherapy group (4 Gy/fraction) with LFM injection. The impact of LFM on tumor growth was evaluated based on the irradiation results. Compared with SFM, the LFM artifacts were significantly smaller (all p