# Radioactive nanoparticle

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A **radioactive nanoparticle** is a [nanoparticle](/source/Nanoparticle) that contains [radioactive materials](/source/Radionuclide). Radioactive nanoparticles have applications in [medical diagnostics](/source/Medical_diagnosis), [medical imaging](/source/Medical_imaging), [toxicokinetics](/source/Toxicokinetics), and [environmental health](/source/Environmental_health), and are being investigated for applications in [nuclear](/source/Nuclear_medicine) [nanomedicine](/source/Nanomedicine). Radioactive nanoparticles present special challenges in [operational health physics](/source/Operational_health_physics) and [internal dosimetry](/source/Internal_dosimetry) that are not present for other substances, although existing [radiation protection](/source/Radiation_protection) measures and [hazard controls for nanoparticles](/source/Health_and_safety_hazards_of_nanomaterials) generally apply.

## Types and applications

### Engineered

Engineered radioactive nanoparticles are used in [medical imaging](/source/Medical_imaging) techniques such as [positron emission tomography](/source/Positron_emission_tomography) and [single-photon emission computed tomography](/source/Single-photon_emission_computed_tomography),[1] and an aerosol of carbon nanoparticles containing [technetium-99m](/source/Technetium-99m) are used in a commercially available procedure for [ventilation/perfusion](/source/Ventilation/perfusion_scan) [scintigraphy](/source/Scintigraphy) of the [lungs.](/source/Lung)[2][: 122–125](/source/Lung) Engineered radioactive nanoparticles are also used as a [radiolabel](/source/Radioactive_tracer) to detect the presence of the nanoparticles themselves in [environmental health](/source/Environmental_health) and [toxicokinetics](/source/Toxicokinetics) studies.[2]: 119–122

Engineered radioactive nanoparticles are being investigated for [therapeutic](/source/Therapeutic) use combining [nuclear medicine](/source/Nuclear_medicine) with [nanomedicine](/source/Nanomedicine), especially for cancer.[2]: 125–130 [Neutron capture therapy](/source/Neutron_capture_therapy_of_cancer) is one such potential application.[1][3] In addition, nanoparticles can help to sequester the toxic daughter nuclides of [alpha emitters](/source/Alpha_emitter) when used in radiotherapy.[4]

Nuclear imaging is non-invasive and has high sensitivity, and nanoparticles are useful as a platform for combining multiple copies of targeting vectors and effectors in order to selectively deliver radioisotopes to a specific region of interest.[5] Other benefits of nanoparticles for diagnostic and therapeutic use include increased blood and tumor retention time, as well as the possibility of using their unique physical and chemical properties in treatment.[citation needed] However, the nanoparticles must be engineered to avoid being recognized by the [mononuclear phagocyte system](/source/Mononuclear_phagocyte_system) and transported to the [liver](/source/Liver) or [spleen](/source/Spleen), often through manipulating their surface functionalization.[3][5]

Targeting techniques include functionalizing radioactive nanoparticles with [antibodies](/source/Antibody) to target them to a specific tissue, and using [magnetic nanoparticles](/source/Magnetic_nanoparticles) that are attracted to a magnet placed over the tumor site.[3] Technetium-99m, [indium-111](/source/Indium-111), and [iodine-131](/source/Iodine-131) are common radioisotopes used for these purposes,[2]: 119–130[3] with many others used as well.[6][7] Radioactive nanoparticles can be produced by either synthesizing the nanoparticles directly from the radioactive materials, or by irradiating non-radioactive particles with [neutrons](/source/Neutron) or [accelerated ions](/source/Ion_beam), sometimes *[in situ](/source/In_situ)*.[2]: 119[8]

### Natural and incidental

As with all nanoparticles, radioactive nanoparticles can also be naturally occurring or incidentally produced as a byproduct of industrial processes. The main source of naturally occurring nanomaterials containing radionuclides is the decay of [radon](/source/Radon) gas, whose immediate decay products are non-gaseous elements that precipitate into nanoscale particles along with atmospheric dust and vapors. Minor natural sources include [primordial radionuclides](/source/Primordial_nuclide) present in the nanoscale portion of [volcanic ash](/source/Volcanic_ash), and primordial and [cosmogenic nuclides](/source/Cosmogenic_nuclide) taken up by plants which are later burned. Radioactive nanoparticles may be incidentally produced by procedures in the [nuclear industry](/source/Nuclear_industry) such as [nuclear reprocessing](/source/Nuclear_reprocessing) and the cutting of contaminated objects.[2]: 16–20

## Health and safety

Radioactive nanoparticles combine the [hazards of radioactive materials](/source/Health_effects_of_radiation) with the [hazards of nanomaterials.](/source/Health_and_safety_hazards_of_nanomaterials)[2][: 2–6](/source/Health_and_safety_hazards_of_nanomaterials) [Inhalation exposure](/source/Inhalation_exposure) is the most common route of exposure to airborne particles in the workplace. Animal studies on some classes of nanoparticles indicate pulmonary effects including [inflammation](/source/Inflammation), [granulomas](/source/Granuloma), and [pulmonary fibrosis](/source/Pulmonary_fibrosis), which were of similar or greater potency when compared with other known [fibrogenic](/source/Fibrosis) materials such as [silica](/source/Silica_gel), [asbestos](/source/Asbestos), and ultrafine [carbon black](/source/Carbon_black). Some studies in cells or animals have shown [genotoxic](/source/Genotoxicity) or [carcinogenic](/source/Carcinogen) effects, or systemic [cardiovascular](/source/Cardiovascular_system) effects from pulmonary exposure.[9][10] The hazards of ionizing radiation depend on whether the exposure is [acute](/source/Acute_radiation_syndrome) or [chronic](/source/Chronic_radiation_syndrome), and includes effects like [radiation-induced cancer](/source/Radiation-induced_cancer) and [teratogenesis](/source/Teratogenesis).[11][12] In some cases, the inherent physicochemical toxicity of the nanoparticle itself may lead to lower [exposure limits](/source/Occupational_exposure_limit) than those associated with the radioactivity alone, which is not the case with most radioactive materials.[2]: 2–6

Radioactive nanoparticles present special challenges in [operational health physics](/source/Operational_health_physics) and [internal dosimetry](/source/Internal_dosimetry) that are not present for other substances, as the nanoparticles' [toxicokinetics](/source/Toxicokinetics) depend on their physical and chemical properties including [size](/source/Particle_size), [shape](/source/Nanoparticle#Morphology_and_structure), and [surface chemistry](/source/Surface_modification). For example, inhaled nanoparticles will deposit in different locations in the lungs, and will be metabolized and transported through the body differently, than vapors or larger particles.[2]: 2–6 There may also be hazards from associated processes such as strong magnetic fields and [cryogens](/source/Cryogenics) used in imaging equipment, and handling of lab animals in experimental studies.[13] Effective risk assessment and communication is important, as both nanotechnology and radiation have unique considerations with public perception.[14]

### Hazard controls

In general, most elements of a standard [radiation protection](/source/Radiation_protection) program are applicable to radioactive nanomaterials, and many [hazard controls for nanomaterials](/source/Health_and_safety_hazards_of_nanomaterials#Hazard_controls) will be effective with the radioactive versions. The [hierarchy of hazard controls](/source/Hierarchy_of_hazard_controls) encompasses a succession of five categories of control methods to reduce the risk of illness or injury. The two most effective are [elimination](/source/Hazard_elimination) and [substitution](/source/Hazard_substitution), for example reducing dust exposure by eliminating a [sonication](/source/Sonication) process or substituting a nanomaterial [slurry](/source/Slurry) or [suspension](/source/Colloid) in a liquid solvent instead of a dry powder. Substitutions should consider both the radioactivity and physicochemical hazards of all the options, and also take into account that radioactive nanomaterials are easier to detect than non-radioactive substances.[2]: 2–6, 35–41

[Engineering controls](/source/Engineering_controls) should be the primary form of protection, including local exhaust systems such as [fume hoods](/source/Fume_hood), [gloveboxes](/source/Glovebox), [biosafety cabinets](/source/Biosafety_cabinet), and [vented balance enclosures](/source/Vented_balance_safety_enclosure); [radiation shielding](/source/Radiation_shielding); and [access control](/source/Access_control) systems.[2]: 41–48 The need for [negative room pressure](/source/Negative_room_pressure) to prevent contamination of outside areas can conflict with the customary use of [positive pressure](/source/Positive_pressure) when pharmaceuticals are being handled, although this can be overcome through use of a cascade pressure system, or by handling nanomaterials in enclosures.[13]

[Administrative controls](/source/Administrative_controls) include procedures to limit radiation doses, and [contamination control](/source/Contamination_control) procedures including encouraging good work practices and monitoring for contamination. [Personal protective equipment](/source/Personal_protective_equipment) is the least effective and should be used in conjunction with other hazard controls. In general, personal protective equipment intended for radioactive materials should be effective with radioactive nanomaterials, including impervious [laboratory coats](/source/Laboratory_coat), [goggles](/source/Goggles), [safety gloves](/source/Safety_glove), and in some cases [respirators](/source/Respirator), although the greater potential penetration through clothing and mobility in air of nanoparticles should be taken into account.[2]: 48–63

## See also

- [Health and safety hazards of nanomaterials](/source/Health_and_safety_hazards_of_nanomaterials)
- [Radiation protection](/source/Radiation_protection)

## References

1. Prasad, Paras N. (2012-05-11). [*Introduction to Nanomedicine and Nanobioengineering*](https://books.google.com/books?id=yp1a9rhftQIC&pg=PA121). John Wiley & Sons. pp. 121–124. ISBN 978-1-118-35107-9.

1. ["Radiation Safety Aspects of Nanotechnology"](http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-15-21975#page=136). *[National Council on Radiation Protection and Measurements](/source/National_Council_on_Radiation_Protection_and_Measurements)*. 2017-03-02. Retrieved 2017-07-07.

1. Hamoudeh, Misara; Kamleh, Muhammad Anas; Diab, Roudayna; Fessi, Hatem (2008-09-15). "Radionuclides delivery systems for nuclear imaging and radiotherapy of cancer". *Advanced Drug Delivery Reviews*. **60** (12): 1329–1346. [doi:10.1016/j.addr.2008.04.013](https://doi.org/10.1016/j.addr.2008.04.013). [PMID 18562040](https://pubmed.ncbi.nlm.nih.gov/18562040)

1. McLaughlin, Mark F.; Woodward, Jonathan; Boll, Rose A.; Wall, Jonathan S.; Rondinone, Adam J.; Kennel, Stephen J.; Mirzadeh, Saed; Robertson, J. David (2013-01-18). "Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy". *PLOS ONE*. **8** (1). [Bibcode:2013PLoSO...854531M](https://ui.adsabs.harvard.edu/abs/2013PLoSO...854531M). [doi:10.1371/journal.pone.0054531](https://doi.org/10.1371/journal.pone.0054531). [ISSN 1932-6203](https://www.worldcat.org/issn/1932-6203). [PMC 3548790](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548790). [PMID 23349921](https://pubmed.ncbi.nlm.nih.gov/23349921)

1. Lewis, Michael R. & Kannan, Raghuraman (November 2014). "Development and applications of radioactive nanoparticles for imaging of biological systems". *Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology*. **6** (6): 628–640. [doi:10.1002/wnan.1292](https://doi.org/10.1002/wnan.1292). [ISSN 1939-0041](https://www.worldcat.org/issn/1939-0041). [PMID 25196269](https://pubmed.ncbi.nlm.nih.gov/25196269)

1. Martín, Isabel García; Frigell, Jens; Llop, Jordi; Marradi, Marco (2016-03-22). "Radiolabelling of NPs Using Radiometals: 99mTc, 68Ga, 67Ga, 89Zr, and 64Cu". *Isotopes in Nanoparticles*. Llop, Jordi; Gomez-Vallejo, Vanessa; Gibson, Peter Neil (eds.). Pan Stanford. pp. 183–229. [doi:10.1201/b19950-9](https://doi.org/10.1201/b19950-9). ISBN 978-981-4669-08-5.

1. Llop, Jordi; Gómez-Vallejo, Vanessa; Martín, Isabel García; Marradi, Marco (2016-03-22). "Radiolabelling of Nanoparticles Using Radiohalogens, 13N, and 11C". *Isotopes in Nanoparticles*. Llop, Jordi; Gomez-Vallejo, Vanessa; Gibson, Peter Neil (eds.). Pan Stanford. pp. 231–260. [doi:10.1201/b19950-10](https://doi.org/10.1201/b19950-10). ISBN 978-981-4669-08-5.

1. Abbas, Kamel; Simonelli, Federica; Holzwarth, Uwe; Gibson, Peter (2009). ["Overview on the production of radioactive nanoparticles for bioscience applications at the JRC Cyclotron – European Commission"](https://ec.europa.eu/jrc/en/publication/contributions-conferences/overview-production-radioactive-nanoparticles-bioscience-applications-jrc-cyclotron). *Journal of Labelled Compounds and Radiopharmaceuticals*. **52**: S231–S255. [doi:10.1002/jlcr.1643](https://doi.org/10.1002/jlcr.1643). Retrieved 2017-07-11.

1. ["Current Intelligence Bulletin 65: Occupational Exposure to Carbon Nanotubes and Nanofibers"](https://www.cdc.gov/niosh/docs/2013-145/). *U.S. [National Institute for Occupational Safety and Health](/source/National_Institute_for_Occupational_Safety_and_Health)*. April 2013. [doi:10.26616/NIOSHPUB2013145](https://doi.org/10.26616/NIOSHPUB2013145). Retrieved 2017-04-26.

1. ["Current Intelligence Bulletin 63: Occupational Exposure to Titanium Dioxide"](https://www.cdc.gov/niosh/docs/2011-160/). *U.S. National Institute for Occupational Safety and Health*. April 2011. [doi:10.26616/NIOSHPUB2011160](https://doi.org/10.26616/NIOSHPUB2011160). Retrieved 2017-04-27.

1. ["Radiation Health Effects"](https://www.epa.gov/radiation/radiation-health-effects). *U.S. [Environmental Protection Agency](/source/United_States_Environmental_Protection_Agency)*. 2017-05-23. Retrieved 2017-07-17.

1. ["Radiation and Its Health Effects"](https://www.nrc.gov/about-nrc/radiation/rad-health-effects.html). *U.S. [Nuclear Regulatory Commission](/source/Nuclear_Regulatory_Commission)*. 2014-10-17. Retrieved 2017-07-17.

1. Reese, Torsten; Gómez-Vallejo, Vanessa; Ferreira, Paola; Llop, Jordi (2016-03-22). "Health and Safety Considerations for Radiolabelled Nanoparticles". *Isotopes in Nanoparticles*. Llop, Jordi; Gomez-Vallejo, Vanessa; Gibson, Peter Neil (eds.). Pan Stanford. pp. 493–512. [doi:10.1201/b19950-19](https://doi.org/10.1201/b19950-19). ISBN 978-981-4669-08-5.

1. Hoover, Mark D.; Myers, David S.; Cash, Leigh J.; Guilmette, Raymond A.; Kreyling, Wolfgang G.; Oberdörster, Günter; Smith, Rachel; Cassata, James R.; Boecker, Bruce B. (2015). ["Application of an Informatics-Based Decision-Making Framework and Process to the Assessment of Radiation Safety in Nanotechnology"](https://www.cdc.gov/niosh/nioshtic-2/20045572.html). *Health Physics*. **108** (2): 179–194. [doi:10.1097/hp.0000000000000250](https://doi.org/10.1097/hp.0000000000000250). [PMID 25551501](https://pubmed.ncbi.nlm.nih.gov/25551501). [S2CID 42732844](https://api.semanticscholar.org/CorpusID:42732844)

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Adapted from the Wikipedia article [Radioactive nanoparticle](https://en.wikipedia.org/wiki/Radioactive_nanoparticle) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Radioactive_nanoparticle?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.