External Beam Radiation Therapy - New Technologies and Treatment Techniques

Recent efforts in utilizing developments in hi-tech research and industry are directed towards four main areas of cancer treatment with radiation. These areas are: (1) tumor diagnostics, (2) tumor targeting by ever more precisely positioned beams of radiation, (3) accurate, Monte Carlo based, dose calculations and (4) better control of dose planning and dose delivery (treatment optimization). Technical advancements in tumor diagnostics are of primary interests and to a large degree they are independent from radiation therapy. They are motivated by general needs to decrease mortality from cancer. However, many of these advancements have to be successfully integrated into radiation therapy to assure the highest quality of cancer treatments. Ultimately, the most accurate targeting of tumors (tumors that are, in fact, moving targets within human body, and, what is more, targets that are not easily identifiable) can be achieved by controlled positioning of beams aided by real time feedback of tumor recognition (verified by appropriate imaging modalities). Accurate dose calculations (dose distributions required for precise prescriptions of treatment) are in practice achievable only through Monte Carlo simulations of radiative particles scattering and energy deposition during their penetration of highly inhomogeneous medium of human tissue. Finally, better control dose delivery (treatment optimization) has most complex character and can be achieved by combining few technological advances. The problem of radiation modality and shaping of 'radiation field' intensity for any particular mode of radiation are essential in this context. The best are scanned beams, intensities of which can be manipulated to provide dose distributions that are 'optimal' with respect to assumed a priori criteria. (authors)