To achieve a good therapeutic ratio the radiation dose to the tumor
should be as high as possible with the lowest possible dose to the surrounding
normal tissue. This is especially the case for brain tumors. Technological advancements
in diagnostic imaging, dose calculations, and radiation delivery systems,
combined with a better understanding of the pathophysiology of brain tumors have led to improvements in the therapeutic results. The widely used
technology of delivering 3-D conformal therapy with photon beams (gamma rays)
produced by Linear Accelerators has progressed into the use of Intensity
modulated radiation therapy (IMRT). Particle beams have been used for several
decades for radiotherapy because of their favorable depth dose characteristics.
The introduction of clinically dedicated proton beam therapy facilities has
improved the access for cancer patients to this treatment. Proton therapy is of
particular interest for pediatric malignancies. These technical improvements
are further enhanced by the evolution in tumor physiology imaging which allows
for improved delineation of the tumor. This in turn opens the potential to
adjust the radiation dose to maximize the radiobiological effects. The advances
in both imaging and radiation therapy delivery will be discussed.
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D. Georg, T. Knoos and B. McClean, “Current Status and Future Perspective of Flattening Filter Free Photon Beams,” Medical Physics, Vol. 38, No. 3, 2011, pp. 1280-1293. http://dx.doi.org/10.1118/ 1.3554643
G. A. Davies, G. Poludniowski and S. Webb, “MLC Tracking for Elekta VMAT: A Modelling Study,” Physics in Medicine and Biology, Vol. 56, No. 23, 2011, pp. 7541-7554.
R. Mohan, A. Mahajan and B. D. Minsky, “New Strategies in Radiation Therapy: Exploiting the Full Potential of Protons,” Clinical Cancer Research, Vol. 19, No. 23, 2013, pp. 6338-6343.
L. Archambault, F. Poenisch, N. Sahoo, D. Robertson and A. Lee, “Verification of Proton Range, Position, and Intensity in IMPT with a 3D Liquid Scintillator Detector System,” Medical Physics, Vol. 39, No. 3, 2012, pp. 1239-1246. http://dx.doi.org/10.1118/1.3681948
S. M. Bentzen and V. Gregoire, “Molecular Imaging-Based Dose Painting: A Novel Paradigm for Radiation Therapy Prescription,” Seminars in Radiation Oncology, Vol. 21, No. 2, 2011, pp. 101-110.
B. S. Laser, T. E. Merchant, D. J. Indelicato, et al., “Evaluation of Children with Craniopharyngioma Using Carbon-11 Methionine PET Prior to Proton Therapy,” Neuro-Oncology, Vol. 15, No. 4, 2013, pp. 506-510.
K. Reddy, D. Damek, L. E. Gaspar, D. Ney and A. Waziri, “Phase II Trial of Hypofractionated IMRT with Temozolomide for Patients with Newly Diagnosed Glioblastoma Multiforme,” International Journal of Radiation Oncology, Biology, Physics, Vol. 84, No. 3, 2012, pp. 655-660.
E. R. Dennis, M. R. Bussiere, A. Niemerko, M. W. Lu and B. C. Fullerton, “A Comparison of Critical Structure Dose and Toxicity Risks in Patients with Low Grade Gliomas Treated with IMRT versus Proton Radiation Therapy,” Technology in Cancer Research and Treatment, Vol. 12, No. 1, 2013, pp. 1-9.
B. S. Athar and H. Paganetti, “Comparison of Second Cancer Risk Due to Out-of-Field Doses from 6-MV IMRT and Proton Therapy Based on 6 Pediatric Treatment Plans,” Radiotherapy & Oncology, Vol. 98, No. 1, 2011, pp. 87-92.
B. J. Moeller, M. Chintagumpala, J. J. Philip, D. R. Grosshanss and M. F. McAleer, “Low Early Ototoxicity Rates for Pediatric Medulloblastoma Patients Treated with Proton Radiotherapy,” Radiation Oncology, Vol. 6, 2011, p. 58. http://dx.doi.org/10.1186/1748-717X-6-58
G. Suneja, P. D. Poorvu, C. Hill-Kayser and R. A. Lustig, “Acute Toxicity of Proton Beam Radiation for Pediatric Central Nervous System Malignancies,” Pediatric Blood & Cancer, Vol. 60, No. 9, 2013, pp. 1431-1436.
H. Hauswald, S. Rieken, S. Ecker, K. A. Kessel and K. Herfarth, “First Experiences in Treatment of Low Grade Glioma Grade I and II with Proton Therapy,” Radiation Oncology, Vol. 7, 2012, p. 189.
M. Mizumoto, T. Okumura, E. Ishikawa, T. Yamamoto and S. Takano, “Reirradiation for Recurrent Malignant Brain Tumor with Radiotherapy or Proton Beam Therapy. Technical Considerations Based on Experience at a Single Institution,” Strahlentherapie und Onkologie, Vol. 189, No. 8, 2013, pp. 656-663.
M. W. McDonald, M. R. Wolanski, J. W. Simmons and J. C. Buschbaum, “Technique for Sparing Previously Irradiated Critical Normal Structures in Salvage Proton Craniospinal Irradiation,” Radiation Oncology, Vol. 8, 2013, p. 14. http://dx.doi.org/10.1186/1748-717X-8-14
F. Vernimmen, J. K. Harris and J. A. Wilson, “Stereotactic Proton Beam Therapy of Skullbase Meningiomas,” International Journal of Radiation Oncology, Biology, Physics, Vol. 99, No. 1, 2001, pp. 99-105.
F. J. Vernimmen, Z. Mohamed, J. Slabbert and J. Wilson, “Long Term Results of Stereotactic Proton Beam Radiotherapy for Acoustic Neuromas,” Radiotherapy and Oncology, Vol. 90, No. 2, 2009, pp. 208-212.
T. Bierre, S. Crijns, P. M. Rosenschold, M. Aznar and L. Specht, “Three Dimensional MRI-Linac Intra-Fraction Guidance Using Multiple Orthogonal Cine-MRI Planes,” Physics in Medicine and Biology, Vol. 58, No. 14, 2013, pp. 4943-4950.
S. Kawata, T. Izumiyama, T. Nagashima, M. Takano and D. Barada, “Laser Ion Acceleration toward Future Ion Beam Cancer Therapy—Numerical Simulation Study,” Laser Therapy, Vol. 22, No. 2, 2013, pp. 103-114.
G. J. Caporaso, T. R. Mackie, S. Sampayan and Y. J. Chen, “A Compact Linac for Intensity Modulated Proton Therapy Based on a Dielectric Wall Accelerator,” Physica Medica, Vol. 24, No. 2, 2008, pp. 98-101.