Heavy Charged Particle Radiation Therapy

Heavy charged particles have two distinct characteristics compared to photons or electrons.8 Dose distributions are highly localized, and the shallow depth sparing effect is significant due to the domination of the Bragg peak. This shallow depth sparing is much more significant than high-energy photons generated by linear accelerators. Additionally, the depth dose after the Bragg peak diminishes nearly to zero. As the Bragg peak depth depends on the incident energy, varying the energy of the primary beam can easily modulate the maximum dose depth. In addition to the advantage in depth dose distribution, the lateral dose gradient is significant at the beam edge.

As previously discussed, heavy charged particles also have a higher radiobiological effectiveness (RBE) and lower oxygen enhancement ratio (OER) because of higher linear energy transfer (LET). These factors may provide more radiobiologic advantages in addition to the physics described above. Recently, isocentrically mounted proton therapy machines are emerging as a competitive radiation therapy modality, as dose conformality has become more of a central issue.8,9 It is possible that the new, clinically oriented proton therapy machines can deliver conformal radiation to the target that will be superior to the current IMRT methods using linear accelerators. However, carefully designed clinical trials are needed to evaluate these potential advantages to proton beam radiation therapy. For small targets, gamma knife irradiation with full frame immobilization represents the current "gold standard" by which other irradiation modalities are to be measured and compared.

A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

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