1. CT-guided fiducial placement for robotic stereotactic body radiotherapy: Efficacy and safety.
- Author
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Loi, Mauro, Carnevale, Maria Grazia, Cataldo, Vanessa Di, Francolini, Giulio, Orsatti, Carolina, Caprara, Luisa, Burchini, Luca, Angelini, Lucia, Doro, Raffaella, Masi, Laura, Bonomo, Pierluigi, and Livi, Lorenzo
- Subjects
FIDUCIAL markers (Imaging systems) ,RADIOTHERAPY safety ,STEREOTACTIC radiotherapy ,X-ray imaging ,PELVIC bones ,TREATMENT delay (Medicine) - Abstract
Robotic Stereotactic Body Radiotherapy (SBRT) employs radiopaque fiducial markers implanted near the tumor for real-time tracking. Fiducials are usually placed before simulation under CT or ultrasound guidance. This represents a limitation to treatment availability and may result in potential treatment delay. In our Institution, an in-house percutaneous CTguided fiducial placement procedure was implemented for pelvic SBRT. The aim of our study is to evaluate the performance and side effects of in-house fiducial placement. Methods: Patients underwent percutaneous fiducial insertion with a 18 G needle under CT guidance, using a radiopaque skin marker to calculate the depth of target location from body surface (Figure 1). One week after placement, simulation CT and orthogonal X-ray imaging were acquired to verify fiducial usability for SBRT tracking. Data from a consecutive cohort of patients treated with fiducial-guided, robotic-arm pelvic SBRT were collected from January 2018 to September 2021. Success rate was defined as the implanted/tracked fiducials ratio. Kruskal Wallis-test was used to compare median success rate over time. Results: In the observed time frame, 282 patients underwent CT-guided fiducial placement, accounting for 883 implanted fiducials (median 3, range 1-4). Implantation sites were the prostate bed, extra-spinal bones and pelvic lymph nodes in 158 (56%), 37 (13%) and 87 (31%) patients, respectively. Side effects consisted of minor bleeding at the insertion site and transient pain requiring medication after 24 hours in 5 patients (2%). No grade >2 toxicity was observed. Overall success rate was 86% (719/833); median success rate per procedure was 100% (range 50-100%). Among the 114 fiducials rejected for tracking, failure was due to migration in 63 cases (55%) and misplacement in 51 cases (45%). Overall success rate increased across the observed time window from 2018 (53/73, 74%) to 2019 (245/293, 84%) to 2020 (246/272, 90%) to 2021 (175/195, 90%) (Figure 2). A consistent, statistically significant improvement in median success rate was observed over time from 2018 (75%, Interquartile Range, IQR 67-100%) to 2019 (100%, IQR 75-100%) to 2020 (100%, IQR 75-100%) to 2021 (100%, IQR 100- 100%) : p= 0.0008. Conclusions: Our in-house percutaneous CT-guided fiducial placement is a safe procedure requiring minimal standard equipment, resulting in success rates comparable with published experiences performed in a dedicated interventional radiology setting. A consistent improvement in median success rate was observed over 4 years, suggesting the need for appropriate interventions to shorten the learning curve. [ABSTRACT FROM AUTHOR]
- Published
- 2022