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Nanoparticles for Radiation Therapy Enhancement: the Key Parameters.

Retif P, Pinel S, Toussaint M, Frochot C, Chouikrat R, Bastogne T, Barberi-Heyob M - Theranostics (2015)

Bottom Line: It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy.Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist.We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy.

View Article: PubMed Central - PubMed

Affiliation: 1. CHR Metz-Thionville, Hôpital de Mercy, Service de radiothérapie, 1 allée du Château, Ars-Laquenexy, 57530, France; ; 2. Université de Lorraine, CRAN, UMR 7039, Campus Sciences, BP 70239, Vandœuvre-lès-Nancy Cedex, 54506, France; ; 3. CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy Cedex, 54506, France;

ABSTRACT
This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development.

No MeSH data available.


Interactions of X-rays with NPs result directly or indirectly in the production of secondary species: photons, electrons and later ROS. Secondary photons or electrons are mostly generated either by photoelectric or Compton effect. The photoelectric effect interaction probability varies with Z4 or Z5 and dominant until the incident photon energy reaches ≈ 500 keV.
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Figure 5: Interactions of X-rays with NPs result directly or indirectly in the production of secondary species: photons, electrons and later ROS. Secondary photons or electrons are mostly generated either by photoelectric or Compton effect. The photoelectric effect interaction probability varies with Z4 or Z5 and dominant until the incident photon energy reaches ≈ 500 keV.

Mentions: Theoretical principles of X-rays interactions with NP have already been described 33. X-ray interactions with matter happen mostly at low energy where the photoelectric effect is dominant (Fig. 5). The photoelectric effect occurs when the incident X-ray photon is absorbed by the atom, resulting in the ejection of an electron. This effect is prevailing until the photon energy reaches a medium energy (e.g. 500 keV for Au) with a cross-section varying with Z4 or Z5 depending on the material and is enhanced by an increased absorption by electron shells (K, L, M, etc.) at low energies. As the atom is left in an ionized state, a characteristic X-ray or an Auger-electron emission follows the ejection of a photoelectron. That is why the radiosensitizing NPs are based on high-Z materials. More theoretical proofs can be found in the literature 6, 55. The Auger effect especially concerns low-Z atoms 56 and therefore would not be a major contributor to the dose deposited in the presence of high-Z NPs. Indeed, it is dominant for Z < 15 but almost equal to 0 for Z > 60 57.


Nanoparticles for Radiation Therapy Enhancement: the Key Parameters.

Retif P, Pinel S, Toussaint M, Frochot C, Chouikrat R, Bastogne T, Barberi-Heyob M - Theranostics (2015)

Interactions of X-rays with NPs result directly or indirectly in the production of secondary species: photons, electrons and later ROS. Secondary photons or electrons are mostly generated either by photoelectric or Compton effect. The photoelectric effect interaction probability varies with Z4 or Z5 and dominant until the incident photon energy reaches ≈ 500 keV.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4493540&req=5

Figure 5: Interactions of X-rays with NPs result directly or indirectly in the production of secondary species: photons, electrons and later ROS. Secondary photons or electrons are mostly generated either by photoelectric or Compton effect. The photoelectric effect interaction probability varies with Z4 or Z5 and dominant until the incident photon energy reaches ≈ 500 keV.
Mentions: Theoretical principles of X-rays interactions with NP have already been described 33. X-ray interactions with matter happen mostly at low energy where the photoelectric effect is dominant (Fig. 5). The photoelectric effect occurs when the incident X-ray photon is absorbed by the atom, resulting in the ejection of an electron. This effect is prevailing until the photon energy reaches a medium energy (e.g. 500 keV for Au) with a cross-section varying with Z4 or Z5 depending on the material and is enhanced by an increased absorption by electron shells (K, L, M, etc.) at low energies. As the atom is left in an ionized state, a characteristic X-ray or an Auger-electron emission follows the ejection of a photoelectron. That is why the radiosensitizing NPs are based on high-Z materials. More theoretical proofs can be found in the literature 6, 55. The Auger effect especially concerns low-Z atoms 56 and therefore would not be a major contributor to the dose deposited in the presence of high-Z NPs. Indeed, it is dominant for Z < 15 but almost equal to 0 for Z > 60 57.

Bottom Line: It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy.Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist.We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy.

View Article: PubMed Central - PubMed

Affiliation: 1. CHR Metz-Thionville, Hôpital de Mercy, Service de radiothérapie, 1 allée du Château, Ars-Laquenexy, 57530, France; ; 2. Université de Lorraine, CRAN, UMR 7039, Campus Sciences, BP 70239, Vandœuvre-lès-Nancy Cedex, 54506, France; ; 3. CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy Cedex, 54506, France;

ABSTRACT
This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development.

No MeSH data available.