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. 2025 May 11;17(5):e83935.
doi: 10.7759/cureus.83935. eCollection 2025 May.

A Quality Control Procedure for Single Fiducial Tracking of Lung Lesions

Martina Descovich  1 , Evan Lau  1 , Katelyn Hasse  1 , Alexander Gottschalk  1
Affiliations

A Quality Control Procedure for Single Fiducial Tracking of Lung Lesions

Martina Descovich et al. Cureus. .

Abstract

Real-time adaptive motion management enables the synchronization of radiation delivery with the patient's breathing motion, thus reducing target margins and normal tissue exposure. The respiratory model is created by correlating the position of external markers placed on the patient's chest with the internal target position extracted from planar X-ray images. While a fiducial-less tracking algorithm is available for lung lesions with high radiographic contrast, many patients require the implantation of radio-opaque markers for localization. To limit the incidence of complications from the implantation procedure, a single fiducial marker may be implanted. As fiducials can migrate following implantation, it is important to verify the relationship between the tumor and the fiducial prior to treatment. The goal of this technical report is to provide a quality control (QC) procedure to assess the possibility of fiducial migration in lung patients treated on the robotic radiosurgery platform.

Keywords: anatomical alignment; breathing motion; dynamic tracking; fiducial migrations; rotational corrections.

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Conflict of interest statement

Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Human Research Protection Program Institutional Review Board (IRB) - Mount Zion Committee issued approval 20-32527. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Fiducial evaluation workflow.
Figure 2
Figure 2. Example of sagittal images from the planning CT (A), exhale phase of the 4DCT (B), and inhale phase of the 4DCT (C), used to evaluate fiducial excursion.
(A) Breath-hold exhale planning CT; (B) Exhale phase of 4DCT; (C) Inhale phase of 4DCT.
Figure 3
Figure 3. Couch shifts after the spine alignment step. The red diamonds indicate the expected shifts based on breathing motion, and the blue circles represent the actual shifts applied during each fraction.
RLL: Right Lower Lobe; LLL: Left Lower Lobe; RML: Right Middle Lobe; RUL: Right Upper Lobe; Fx#: Fraction Number; SI: Superior-Inferior; LR: Left-Right; AP: Anterior-Posterior.
See this image and copyright information in PMC

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