Requirements for Designing an Effective Metallic Nanoparticle (NP)-Boosted Radiation Therapy (RT)

Abstract

Many different tumor-targeted strategies are under development worldwide to limit the side effects and improve the effectiveness of cancer therapies. One promising method is to enhance the radiosensitization of the cancer cells while reducing or maintaining the normal tissue complication probability during radiation therapy using metallic nanoparticles (NPs). Radiotherapy with MV photons is more commonly available and applied in cancer clinics than high LET particle radiotherapy, so the addition of high-Z NPs has the potential to further increase the efficacy of photon radiotherapy in terms of NP radiosensitization. Generally, when using X-rays, mainly the inner electron shells are ionized, which creates cascades of both low and high energy Auger electrons. When using high LET particles, mainly the outer shells are ionized, which give electrons with lower energies than when using X-rays. The amount of the produced low energy electrons is higher when exposing NPs to heavy charged particles than when exposing them to X-rays. Since ions traverse the material along tracks, and therefore give rise to a much more inhomogeneous dose distributions than X-rays, there might be a need to introduce a higher number of NPs when using ions compared to when using X-rays to create enough primary and secondary electrons to get the desired dose escalations. This raises the questions of toxicity. This paper provides a review of the fundamental processes controlling the outcome of metallic NP-boosted photon beam and ion beam radiation therapy and presents some experimental procedures to study the biological effects of NPs’ radiosensitization. The overview shows the need for more systematic studies of the behavior of NPs when exposed to different kinds of ionizing radiation before applying metallic-based NPs in clinical practice to improve the effect of IR therapy.

NVCL-Based Galacto-Functionalized and Thermosensitive Nanogels with GNRDs for Chemo/Photothermal-Therapy

“…The physical effect occurs by the generation of photoelectrons and Auger electrons, while the chemical/biological effects include oxidative stress and reactive oxygen species production, DNA damage and reduced repair, cell cycle arrest, and bystander effects. These synergistic effects highlight the great importance of targeting GNRDs in cancer treatment [ 14 , 15 ].…”

The Effect of Hypoxia on Relative Biological Effectiveness and Oxygen Enhancement Ratio for Cells Irradiated with Grenz Rays

“…The RBE value for GT is 1.2–2.4 for severely hypoxic tumors, and it suggests the dose for GT can be as low as half to the total dose prescribed for XT and can reduce the complications. Further studies could use a combination of nanoparticles to increase the dose [ 93 ] and the synergistic effects could further improve the outcomes of clinical treatment.…”

Nano-Drug Delivery Systems Entrapping Natural Bioactive Compounds for Cancer: Recent Progress and Future Challenges

“…It is also employed in the production of bioactive compounds and phytochemical constituents ( 236 ). In now a day the clinical trial is performed in some inorganic nanomaterials such as gold nanoparticles and silica nanoparticles ( 237 ). Folic acid surface modification improves the targetability of curcumin magnetic nanoparticles.…”