Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.3
Medical

1.2.3.3
Applications -
Beneficial Effects

"Selective deletion of radio-sensitive suppressor T cells by low dose total body irradiation (TBI) is believed to be part of the mechanism of anti-tumor effect of this irradiation. Recently, with the concept of ‘Radiation Hormesis’ being introduced by T. D. Luckey, new experimental data and hypotheses have been reported. It is possible that adaptive feedback control signals are stimulated to upregulate stem cells and prolifer-ative populations in response to cell injury and cell death induced by low dose irradiation as described by Fabricant and Makinodan.

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Table 1

Table 2

"Two-color analyses of peripheral blood lymphocytes using flow cytometry in 9 patients with non-Hodgkin’s lymphoma, who received low dose total body irradiation (TBI) or half body irradiation (HBI), were performed to look at the influence of low dose irradiation on lymphocytes and its anti-tumor effects.

"The results of the present study are: significant increase in the proportion of helper T, helper-inducer T, and active helper/inducer T cells; slight increase of cytotoxic T cells; and decrease of suppressor-inducer T and suppressor T cells. Since low dose TBI preceded the other treatments such as primary site irradiation and multiple agent chemotherapy in three cases, the antitumor effect of TBI was able to be investigated. All three patients showed at least partial responses, especially in case 7 (stage III) where almost all tumors disappeared after only TBI.

"In patients without pretreatment, the extent of bone marrow suppression of two or three times per week TBI using 0.1 Gy as a dose/fraction and 1.5 Gy as a total dose was not as serious and seemed to pose no problem clinically. The results of the present study support the ideas presented by Fabricant and Makinodan, where the proportion of the helper T cells would increase in response to low dose irradiation as homeostatic adaptation of lymphoid tissue."
 

Radiation protection interests have suppressed the evidence, and have continued to suppress confirmatory and follow-on work, at the high cost of failing to provide substantial potential medical benefits and preventing premature deaths in addition to costly and unnecessary radiation protection practices and programs.