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Review
. 2019 Mar;92(1095):20180466.
doi: 10.1259/bjr.20180466. Epub 2018 Nov 7.

Spatially fractionated proton minibeams

Juergen Meyer  1 , John Eley  2 , Thomas E Schmid  3   4   5 , Stephanie E Combs  3   4   5 , Remi Dendale  6 , Yolanda Prezado  7
Affiliations
Review

Spatially fractionated proton minibeams

Juergen Meyer et al. Br J Radiol. 2019 Mar.

Abstract

Extraordinary normal tissue response to highly spatially fractionated X-ray beams has been explored for over 25 years. More recently, alternative radiation sources have been developed and utilized with the aim to evoke comparable effects. These include protons, which lend themselves well for this endeavour due to their physical depth dose characteristics as well as corresponding variable biological effectiveness. This paper addresses the motivation for using protons to generate spatially fractionated beams and reviews the technological implementations and experimental results to date. This includes simulation and feasibility studies, collimation and beam characteristics, dosimetry and biological considerations as well as the results of in vivo and in vitro studies. Experimental results are emerging indicating an extraordinary normal tissue sparing effect analogous to what has been observed for synchrotron generated X-ray microbeams. The potential for translational research and feasibility of spatially modulated proton beams in clinical settings is discussed.

Keywords: Equivalent Uniform Dose; Microbeam Radiotherapy; Normal Tissue Sparing; Relative Biological Effectiveness; Spatially Fractionated Radiation Therapy.

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Figures

Figure 1.
Figure 1.
Illustration of spatially fractionated proton beams that produce a uniform dose at depth. (a) multiplanar beams generated with a collimator and (b) pencil beams generated with steering magnets.
Figure 2.
Figure 2.
Concept of proton minibeams. Simulated dose distributions with spread out Bragg peak for (a) homogeneous broad beam (top) and (b) minibeam (bottom) irradiation. Figure adapted from Sammer et al with permission.
Figure 3.
Figure 3.
Comparison of the RBEDSB (left axis) at different depths for different nominal proton beam energies simulated on the University of Washington research proton beamline. The depth of the BP is shown on the right axis. BP, Bragg peak.
See this image and copyright information in PMC

References

    1. Garibaldi C, Jereczek-Fossa BA, Marvaso G, Dicuonzo S, Rojas DP, Cattani F, et al. . Recent advances in radiation oncology. Ecancermedicalscience 2017; 11: 785. doi: 10.3332/ecancer.2017.785 - DOI - PMC - PubMed
    1. Köhler A. Theorie einer Methode, bisher unmöglich unanwendbar hohe Dosen Röntgenstrahlen in der Tiefe des Gewebes zur therapeutischen Wirksamkeit zu bringen ohne schwere Schädigung des Patienten, zugleich eine Methode des Schutzes gegen Röntgenverbrennung überhaupt. Fortschr Geb Roentgenstr 1909; 14: 27–9.
    1. Laissue JA, Blattmann H, Slatkin DN, Köhler A. Inventor of grid therapy. Z Med Phys 1874-19472012; 22: 90–9. - PubMed
    1. Freid JR, Lipman A, Jacobson LE. Roentgen therapy through a grid for advanced carcinoma. Am J Roentgenol Radium Ther Nucl Med 1953; 70: 460–76. - PubMed
    1. Jolles B, Russ S. X-ray Sieve Therapy in Cancer. A Connective Tissue Problem. Boston: The British Institute of Radiology.; 1953.