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245:") shows how the originally monoenergetic proton beam with the sharp peak is widened by increasing the range of energies, so that a larger tumor volume can be treated. The plateau created by modifying the proton beam is referred to as the spread out Bragg Peak, or SOBP, which allows the treatment to conform to not only larger tumors, but to more specific 3D shapes. This can be achieved by using variable thickness
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increases as the charged particle's energy decreases. Energy lost by charged particles is inversely proportional to the square of their velocity, which explains the peak occurring just before the particle comes to a complete stop. In the upper figure, it is the peak for alpha particles of 5.49 MeV
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This characteristic of proton beams was first recommended for use in cancer therapy by Robert R. Wilson in his 1946 article, Radiological Use of Fast
Protons. Wilson studied how the depth of proton beam penetration could be controlled by the energy of the protons. This phenomenon is exploited in
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599:"Difference in the relative biological effectiveness and DNA damage repair processes in response to proton beam therapy according to the positions of the spread out Bragg peak"
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like spinning wedges. Momentum cooling in cyclotron-based proton therapy facilities enables a sharper distal fall-off of the Bragg peak and the attainment of high dose rates.
687:"Systematics of relative biological effectiveness measurements for proton radiation along the spread out Bragg peak: experimental validation of the local effect model"
170:, who discovered it in 1903 using alpha particles from radium, and wrote the first empirical formula for ionization energy loss per distance with Richard Kleeman.
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Maradia, V., Meer, D., Dölling, R. et al. Demonstration of momentum cooling to enhance the potential of cancer treatment with proton therapy. Nat. Phys. (2023).
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644:"Robert R. Wilson (1914–2000): the first scientist to propose particle therapy—use of particle beam for cancer treatment"
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moving through air. In the lower figure, it is the narrow peak of the "native" proton beam curve which is produced by a
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Particle Beam
Radiation Therapies for Cancer [Internet]. Comparative Effectiveness Technical Briefs, No. 1
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Bragg, W. H. (1904). "LXXIII. On the absorption of α rays, and on the classification of the α rays from radium".
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342:"XXXIX. On the α particles of radium, and their loss of range in passing through various atoms and molecules"
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448:. Rockville (MD): Agency for Healthcare Research and Quality (US). pp. ES1–ES5.
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The London, Edinburgh, and Dublin
Philosophical Magazine and Journal of Science
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The London, Edinburgh, and Dublin
Philosophical Magazine and Journal of Science
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in passing through tissue, compared to the absorption of a photon or x-ray beam
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being treated while minimizing the effect on the surrounding healthy tissue.
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of cancer, specifically in proton therapy, to concentrate the effect of light
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The Bragg curve of 5.49 MeV alphas in air has its peak to the right and is
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is a pronounced peak on the Bragg curve which plots the energy loss of
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198:. The figure also shows the absorption of a beam of energetic
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Path length of maximum energy loss of ionizing radiation
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along its path. A peak occurs because the interaction
62:. Unsourced material may be challenged and removed.
508:"Proton Beam Radiotherapy - The State of the Art1"
461:"Creating a spread-out Bragg peak in proton beams"
340:Bragg, William Henry; Kleeman, Richard (1905).
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537:https://doi.org/10.1038/s41567-023-02115-2
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142:to the left, unlike the x-ray beam below.
122:Learn how and when to remove this message
241:The blue curve in the figure ("modified
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217:The dose produced by a native and by a
154:during its travel through matter. For
506:Paganetti, Harald; Bortfeld, Thomas.
292:Charlie Ma, C-M; Lomax, Tony (2012).
181:atoms of the material and deposits a
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442:Trikalinos, TA; et al. (2009).
296:. Boca Raton: CRC Press. p. 4.
60:adding citations to reliable sources
648:Radiological Physics and Technology
259:Stopping power (particle radiation)
642:Endo, Masahiro (20 October 2017).
397:"Radiological Use of Fast Protons"
14:
685:Grun, Rebecca (10 January 2017).
25:, also known as reflections, see
21:For use of this term to describe
395:Wilson, Robert R. (1946-11-01).
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691:Physics in Medicine and Biology
465:Physics in Medicine and Biology
47:needs additional citations for
597:Hojo, Hidehiro (3 July 2017).
375:Brookhaven National Laboratory
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748:Experimental particle physics
294:Proton and carbon ion therapy
558:Radiation Physics Principles
459:Jette, D.; Chen, W. (2011).
477:10.1088/0031-9155/56/11/N01
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703:10.1088/1361-6560/62/3/890
552:Wagenaar, Douglas (1995).
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661:10.1007/s12194-017-0428-z
616:10.1186/s13014-017-0849-1
584:. Oxford University Press
357:10.1080/14786440509463378
327:10.1080/14786440409463245
177:moves through matter, it
371:"Bragg Curves and Peaks"
554:"7.1.3 The Bragg Curve"
269:Linear energy transfer
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219:modified proton beam
192:particle accelerator
56:improve this article
168:William Henry Bragg
743:Ionizing radiation
603:Radiation Oncology
351:. 10:57: 318-340.
321:. 8(48): 719–725.
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152:ionizing radiation
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722:. Retrieved
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562:the original
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71:"Bragg peak"
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54:Please help
49:verification
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247:attenuators
243:proton beam
208:exponential
737:Categories
654:(1): 1–6.
609:(1): 111.
588:27 January
568:27 January
521:27 January
380:27 January
280:References
148:Bragg peak
82:newspapers
421:0033-8419
401:Radiology
232:ion beams
724:19 March
719:24855475
711:28072575
670:29058267
635:28673358
493:37517481
485:21558588
429:20274616
253:See also
164:ion rays
678:3526846
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234:on the
200:photons
194:of 250
179:ionizes
156:protons
96:scholar
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204:X-rays
160:α-rays
140:skewed
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715:S2CID
674:S2CID
511:(PDF)
489:S2CID
345:(PDF)
236:tumor
103:JSTOR
89:books
726:2021
707:PMID
666:PMID
631:PMID
590:2016
570:2016
523:2016
515:AAPM
481:PMID
425:PMID
417:ISSN
382:2016
298:ISBN
183:dose
146:The
75:news
699:doi
656:doi
621:PMC
611:doi
473:doi
409:doi
353:doi
323:doi
196:MeV
58:by
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