Improved normal tissue protection by proton and X-ray microchannels compared to homogeneous field irradiation.
The risk of developing normal tissue injuries often limits the radiation dose that can be applied to the tumour in radiation therapy. Microbeam Radiation Therapy (MRT), a spatially fractionated photon radiotherapy is currently tested at the European Synchrotron Radiation Facility (ESRF) to improve normal tissue protection. MRT utilizes an array of microscopically thin and nearly parallel X-ray beams that are generated by a synchrotron. At the ion microprobe SNAKE in Munich focused proton microbeams ("proton microchannels") are studied to improve normal tissue protection. Here, we comparatively investigate microbeam/microchannel irradiations with sub-millimetre X-ray versus proton beams to minimize the risk of normal tissue damage in a human skin model, in vitro. Skin tissues were irradiated with a mean dose of 2 Gy over the irradiated area either with parallel synchrotron-generated X-ray beams at the ESRF or with 20 MeV protons at SNAKE using four different irradiation modes: homogeneous field, parallel lines and microchannel applications using two different channel sizes. Normal tissue viability as determined in an MTT test was significantly higher after proton or X-ray microchannel irradiation compared to a homogeneous field irradiation. In line with these findings genetic damage, as determined by the measurement of micronuclei in keratinocytes, was significantly reduced after proton or X-ray microchannel compared to a homogeneous field irradiation. Our data show that skin irradiation using either X-ray or proton microchannels maintain a higher cell viability and DNA integrity compared to a homogeneous irradiation, and thus might improve normal tissue protection after radiation therapy.
Universität der Bundeswehr München, Neubiberg, Germany.
S
S
Girst
Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
C
C
Marx
European Synchrotron Radiation Facility, Grenoble Cedex, France.
E
E
Bräuer-Krisch
European Synchrotron Radiation Facility, Grenoble Cedex, France.
A
A
Bravin
German Cancer Research Centre (DKFZ), Heidelberg, Germany; The Institute of Cancer Research, Sutton, United Kingdom.
S
S
Bartzsch
German Cancer Research Centre (DKFZ), Heidelberg, Germany; The Institute of Cancer Research, Sutton, United Kingdom.
U
U
Oelfke
Universität der Bundeswehr München, Neubiberg, Germany.
C
C
Greubel
Universität der Bundeswehr München, Neubiberg, Germany.
J
J
Reindl
Universität der Bundeswehr München, Neubiberg, Germany; Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
C
C
Siebenwirth
Universität der Bundeswehr München, Neubiberg, Germany.
O
O
Zlobinskaya
Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
G
G
Multhoff
Universität der Bundeswehr München, Neubiberg, Germany.
G
G
Dollinger
Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany.
T E
TE
Schmid
Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany. Electronic address: wilkens@tum.de.
J J
JJ
Wilkens
D000818:Animals; D040761:Biomimetic Materials / Q000528:radiation effects; D019583:Dose Fractionation, Radiation; D004867:Equipment Design; D019317:Evidence-Based Medicine; D006801:Humans; D059351:Organ Sparing Treatments / Q000379:methods; D061766:Proton Therapy / Q000009:adverse effects; D011522:Protons; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011835:Radiation Protection / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000009:adverse effects*; D012016:Reference Values; D012867:Skin / Q000293:injuries* / Q000473:pathology / Q000528:radiation effects*; D017356:Synchrotrons; D013673:Technology Assessment, Biomedical; D016896:Treatment Outcome
D011522:Protons
In vitro skin model; Microbeams; Protons; X-rays