Response of the rat spinal cord to X-ray microbeams

Laissue, Jean A.; Bartzsch, Stefan; Blattmann, H.; Bräuer-Krisch, Elke; Bravin, A.; Dalléry, Dominique; Djonov, Valentin; Hanson, A.L.; Hopewell, J. W.; Kaser‐Hotz, Barbara; Keyriläinen, Jani; Laissue, Pierre Philippe; Miura, Michiko; Serduc, Raphaël; Siegbahn, Albert; Slatkin, Daniel N.

doi:10.1016/j.radonc.2012.12.007

Cited by 56 publications

(44 citation statements)

References 29 publications

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“…It thus further builds up a comprehensive database for the RBE of late responding normal CNS tissue. For this, the rat spinal cord is a well established model [18][19][20][21][22][23][24] which has been used previously to study the RBE of carbon ions [1,2,10,11]. However, presently existing datasets are rather small and even the largest one, originating from historical studies [1,2], investigated only the dose-but not the LET-dependence of the RBE.…”

Section: Discussionmentioning

confidence: 99%

Split dose carbon ion irradiation of the rat spinal cord: Dependence of the relative biological effectiveness on dose and linear energy transfer

Saager

Glowa

Peschke

et al. 2015

Radiotherapy and Oncology

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Section: Discussionmentioning

confidence: 99%

Split dose carbon ion irradiation of the rat spinal cord: Dependence of the relative biological effectiveness on dose and linear energy transfer

Saager

Glowa

Peschke

et al. 2015

Radiotherapy and Oncology

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“…The radiotoxic dose is therefore confined to a very narrow zone while the integrity and functionality of adjacent normal tissue in the valleys between the peaks is barely damaged. Further, spatial fractionation results in a large specific contact surface between peak and valley zones, much larger than that provided by a single broad beam [31]. This extended contact surface is instrumental for the repair of heavily irradiated tissues in peak regions by much less damaged tissues in the valleys.…”

Section: Mrt Versus Broad Beam Irradiationmentioning

confidence: 99%

Effects of microbeam radiation therapy on normal and tumoral blood vessels

et al. 2015

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Microbeam radiation therapy (MRT) is a new form of preclinical radiotherapy using quasi-parallel arrays of synchrotron X-ray microbeams. While the deposition of several hundred Grays in the microbeam paths, the normal brain tissues presents a high tolerance which is accompanied by the permanence of apparently normal vessels. Conversely, the efficiency of MRT on tumor growth control is thought to be related to a preferential damaging of tumor blood vessels. The high resistance of the healthy vascular network was demonstrated in different animal models by in vivo biphoton microscopy, magnetic resonance imaging, and histological studies. While a transient increase in permeability was shown, the structure of the vessels remained intact. The use of a chick chorioallantoic membrane at different stages of development showed that the damages induced by microbeams depend on vessel maturation. In vivo and ultrastructural observations showed negligible effects of microbeams on the mature vasculature at late stages of development; nevertheless a complete destruction of the immature capillary plexus was found in the microbeam paths. The use of MRT in rodent models revealed a preferential effect on tumor vessels. Although no major modification was observed in the vasculature of normal brain tissue, tumors showed a denudation of capillaries accompanied by transient increased permeability followed by reduced tumor perfusion and finally, a decrease in number of tumor vessels. Thus, MRT is a very promising treatment strategy with pronounced tumor control effects most likely based on the anti-vascular effects of MRT.

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“…The general tissue-sparing effect of minibeams and their smaller counterpart microbeams [<0.3 mm FWHM] has been established with deuterons (9), synchrotron x-rays (10–18), carbon ions (18), and microchannel protons (19). First, it was found that the threshold dose for damage in the mouse cerebellum from deuteron pencil beams of 0.025, 0.075, 0.25, and 1.0 mm diameter are 4,000, 500, 360, and 140 Gy, respectively (9).…”

Section: Introductionmentioning

confidence: 99%

“…Second, the rat cerebellum tolerated arrays of parallel, 37-μm planar synchrotron x-rays spaced 75 μm on-center at 250 Gy in-beam dose (10). The study triggered a line of research called microbeam radiation therapy in the U.S. (11,14,15,17) and in France (12,13,16,18). Among others, the studies showed that planar synchrotron x-ray beams as thick as 0.68 mm still retain much of their tissue-sparing effect (14).…”

Section: Introductionmentioning

confidence: 99%

Minibeam Therapy With Protons and Light Ions: Physical Feasibility and Potential to Reduce Radiation Side Effects and to Facilitate Hypofractionation

Dilmanian

Eley

Krishnan

2015

International Journal of Radiation Oncology*Biology*Physics

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Purpose Despite several advantages of proton therapy over megavoltage x-ray therapy its lack of proximal-tissue sparing is a concern. The method presented here adds proximal-tissue sparing to protons and light ions by turning their uniform incident beams into arrays of parallel, small or thin (0.3 mm) pencil or planar minibeams, which are known to spare tissues. As these minibeams penetrate the tissues they gradually broaden and merge with each other to produce a solid beam. Methods and Materials Broadening of 0.3-mm-diameter, 109-MeV proton pencil minibeams was measured using a stack of radiochromic films with plastic spacers. Monte Carlo simulations were used to evaluate the broadening in water of minibeams of protons and several light ions and the dose from neutron generated by collimator. Results A central parameter was the tissue depth where the beam full-width-at-half-maximum (FWHM) reached 0.7 mm, beyond which tissue sparing decrease. This depth was measured to be 22 mm for 109-MeV protons in a film-stack. It was also found by simulations a) for protons to be 23.5 mm for 109-MeV pencil minibeams and 26 mm for 116-MeV planar minibeams, and b) for light ions, all with 10-cm range in water, to increase with particle size; specifically it was 51 mm for Li-7 ions. The ~2.7% photon equivalent neutron skin dose from the collimator was reduced 7-fold by introducing a gap in between the collimator and the skin. Conclusions Proton minibeams can be implemented at existing particle therapy centers. Because they spare the shallow tissues they could augment the efficacy of proton therapy and light particle therapy particularly in treating tumors that benefit from sparing of proximal tissues such as pediatric brain tumors. They should also allow hypofractionated treatment of all tumors by allowing the use of higher incident doses with less concern about proximal tissue damage.

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Response of the rat spinal cord to X-ray microbeams

Cited by 56 publications

References 29 publications

Split dose carbon ion irradiation of the rat spinal cord: Dependence of the relative biological effectiveness on dose and linear energy transfer

Split dose carbon ion irradiation of the rat spinal cord: Dependence of the relative biological effectiveness on dose and linear energy transfer

Effects of microbeam radiation therapy on normal and tumoral blood vessels

Minibeam Therapy With Protons and Light Ions: Physical Feasibility and Potential to Reduce Radiation Side Effects and to Facilitate Hypofractionation

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