Recent Advances in Brachytherapy Using Radioactive Nanoparticles: An Alternative to Seed-Based Brachytherapy

Abstract

Interstitial brachytherapy (BT) is generally used for the treatment of well-confined solid tumors. One example of this is in the treatment of prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several posttreatment adverse effects or symptoms and operational and logistical complications associated with it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor-specific biomolecules, injected intratumorally, have been reported as an alternative to seed-based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article, we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed-based BT. Here, we discuss the limitations of current seed-based BT and advantages of radio-NPs for BT applications. Recent progress on the types of radio-NPs, their features, synthesis methods, and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in BT treatments are also discussed.

Radiolabeled Gold Nanoseeds Decorated with Substance P Peptides: Synthesis, Characterization and In Vitro Evaluation in Glioblastoma Cellular Models

“…The designed AuNP-SP and AuNP-SPTyr8 were thought as nanoseeds for internal radiation therapy of glioblastoma, upon labeling with therapeutic radionuclides (e.g., 125 I and 177 Lu) and intratumoral administration, in alternative to classical brachytherapy seeds [ 54 ]. The decoration of these NPs with SP peptides for NK1R targeting was expected to promote the internalization in glioblastoma cells to prolong tumor retention and enhance radiobiological effects.…”

Image-Guided Nanodelivery of Pt(IV) Prodrugs to GRP-Receptor Positive Tumors

“…Furthermore, such a strategy allows a molecularly targeted image-guided approach to follow the local delivery of the cytotoxic drugs, being particularly useful for aggressive GRPR-positive solid tumors. In a way, this approach is related to a kind of nano-brachytherapy, using nanoseeds functionalized with tumor-specific biomolecules and injected intratumorally, which in recent year started to be envisaged for the delivery of therapeutic radionuclides as an alternative to classical brachytherapy seeds 48 . Most importantly, these injectable nanoseeds can reduce the trauma inherent to surgical implantation of the brachytherapy seeds in clinical use, namely in the case of prostate cancer.…”

Universal Chelator-Free Radiolabeling of Organic and Inorganic-Based Nanocarriers with Diagnostic and Therapeutic Isotopes for Internal Radiotherapy

“…In internal radiotherapy, radioactive sources are located inside or near the tumor to reach a maximum efficiency from local treatment . Recently, NPs drew significant attention as radionuclide carriers for internal radiotherapy (the so-called nanobrachytherapy) due to their advantages such as (i) precise and targeted delivery of various therapeutic agents; (ii) control over the size and shape of NPs, which allows achieving a homogenous NP distribution within tumors after their local injection; and (iii) additional features such as bioimaging, local heating at the nanoscale, nanothermometry, and others, which depend on the nature of carrier NPs. − …”