Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO₄ and biodegradable polymer for proton therapy

Abstract

BaSO4 mixed with PBS is a good contrast agent in biodegradable polymer marker because of minimal artifacts in x-ray images and minimal dose reduction in proton therapy. The flexibility of the size is considered to be an advantage of this material over solid type fiducials.

Biodegradable Fiducial Markers for Bimodal Near-Infrared Fluorescence- and X-ray-Based Imaging

“…Nonetheless, the released products of basic composite degradation did not affect the viability of cells in the performed cytotoxicity test (Figure F). Moreover, the safety of the usage of BaSO 4 and iohexol was also reported in other works. ,− …”

“…The majority of them require a temporary application of fiducial markers (FMs) implanted close to or in the surgical field as a reference point to precisely label tumor localization or determine the tumor margin. , For X-ray-based real-time imaging, mainly metallic FMs are used. However, after fulfilling the function, e.g., within a few months of adjuvant therapy, the nondegradable FMs are often removed due to possible interference during future diagnostic imaging , or the patient’s discomfort or pain. , Therefore, the development of materials for FMs with a defined lifetime in vivo may improve the quality of convalescence and life of the patients.…”

“…The first is a water-soluble, small-molecule iodinated nonionic contrast agent, which exhibits a lower incidence of adverse health effects than iodinated ionic contrast agents. The second, BaSO 4 , is a water-insoluble crystalline solid, which is nondegradable (e.g., PolyMark Fiducial Marker) and has been tested in biodegradable systems. ,, …”

Recent Advances in Polyesters for Biomedical Imaging

“…It can therefore be seen that the dosage used for X‐rays in the clinical setting is low enough to prevent injury from radiation, even after repeated doses over time. To decrease the exposure to ionization radiation and improve the contrast between tissues and polyesters, barium‐ and iodine‐containing compounds have been commonly used in nanoparticles, microspheres, and polymeric blends . These contrast agents have also been conjugated onto polymers and been incorporated through functionalization of monomers …”

Preparation of Biopex-Supported Gold Nanoparticles as Potential Fiducial Markers for Image-Guided Radiation Therapy

“…Normally, fiducial markers are metal-based solid implants with large physical dimensions. ,, These large-sized fiducial markers are considered highly invasive, especially for the elderly, and require complicated insertion procedures, which might result in the risk of complications, such as pneumothorax, − infection, , and bleeding. It is therefore critical to explore minimally invasive alternatives to the current large-sized tissue markers, such as injectable fiducial markers (colloidal- or liquid-like) − and several commercial markers, including gold anchor fiducial markers, polymark fiducial markers, and BioXmark.…”