| Objective: In order to provide the evidence of protection of hypoxic radiotherapy to thenormal tissues of bone marrow.peripheral lymphocytes and enterocytes and to confirm therelationship between the protection mentioned above and the long-term survival rate,the mice testsand clinical trials of hypoxic radiotherapy tor the patients with carcinomas in pelvis had beendone,respectively.Materials and methods: Kun Ming mice were divided into four groups: Air(inhalation ofair before and during radiation.),HO(inhalation of carbogen for 5 minutes before and during theradiation.),LO(inhalation of low concentration oxygen for 3 minutes before and during theradiation.),and HO+LO(inhalation of carbogen for 5 minutes before the radiation, then switched toinhalation of low concentration oxygen right at the beginning of radiation, and continued till theend of radiation.). Lower half-body irradiation was done to every mouse with 6MV X-rays at adifferent dose point depending on different target tissue. At the 24 houres after radiation,the bloodwas taken from the tail vein,made blood smear and micronucleus frequency of peripherallymphocytes was counted under the high power lens.Then the mice were killed and the thighbone marrow of them were removed.After routine histological processing,stained withhaematoxylin and eosin,the pathological changes of the bone marrow were observed.Themicronucleus of polychromatic erythrocytes(PCES) in mouse bone marrow were detected and therelationship between the micronucleus frequency of polychromatic erythrocytes and radiation dosewas established and the dose- effect curves fitted.Oxygen enhancement ratio(OER) andradioprotective factor(RPF) were calculated. At the 3.5 days after radiation the animals were killed.Segments of jejunum were removed and, after routine histological processing, transverse sectionswere cut and stained with haematoxylin and eosin. The relationship between total cell survival percircumference and radiation dose was established, and dose-survival curves were fitted.ThenSERs and RPFs were respectively obtained.In clinic, 113 patients with carcinoma of uterine cervixand 148 patients with carcinoma of rectem after operation were, respectively, randomly dividedby the envelope method into two groups: hypoxia radiotherapy group (HRG) and conventionalradiotherapy group (CRG).The patients in HRG were inhaling the hypoxia gas (oxygen physicalvolume: 0.105) for two minutes before the starting of radiotherapy till the end of radiotherapy ofeach field and then repeated.The duration of irradiation to each field was less than five minutes.The patients in control group (CRG) were only treated with conventional radiotherapy.Theireffects of the near future and the long-term survival rates were observed.Results: In animal experiment, the RPFs and SERs with hypoxic radiation are 1.48 and 1.44for the marrow, 1.39 and 1.38 for peripheral lymphocytes, 1.25 and 0.80 for enterocytes,respectively.In clinical trials,contrast with conventional radiotherapy group, the decreased value ofperipheral blood white cells after hypoxia radiotherapy in HRG was obviously diminished(P＜0.05);The cellular immune functions were obviously protected(P＜0.01); The incidence ofcomplications such as radiation proctitis and radiocystitis was also of statistically significance(P＜0.01 and P＜0.05, respectively); The five-year survival rates of the two kinds of carcinomas inpelvis obviously increased.(P＜0.05).Conclutions:①The normal tissues of bone marrow, peripheral lymphocytes andenterocytes can be protected by hypoxic radiation on pelvis in the mice tests.②The peripheral blood white cells and the cellular immune functions can also be obviously protected by hypoxicradiotherapy on the patients with carcinomas located in pelvis. Radiation proctitis and radiocystitiscan be obviously released by the method. 3 Both the long-term survival rate and life quality ofthese patients are expected to he improved. It is safe, pragmatic and feasible to put the method ofhypoxic radiotherapy into clinical practice.
|
PDF Full Text Request