A dosimetric method of total body irradiation

The determination of the dose delivered to the body during Total Body Irradiation (TBI) is not easy, as direct measurements are impossible. This article presents the intention to develop a systematic and simple method for absorbed dose determination in(60)Co TBI using mid plane dose factors (MDF) and external measurements, i.e. entrance and exit dose readings by semiconductor detectors. In order to perform the radiation field analysis prior to TBI treatment, a special silicon n-type detector with increased sensitivity (1200 nC/Gy) was used. The dependence of the calibration factor of this detector exposed to different dose rates in standard and TBI conditions was investigated. A theoretical model of anthropomorphic phantoms of cylindrical ellipsoid shape was established. The software made it possible to generalize the applicability of TBI dosimetry to any individual case of real patient data. A quality assurance analysis of dosimetric results of 350 patients, who underwent TBI during a 17-year period, was performed.     

Lipid peroxidation and total antioxidant status in patients with breast cancer

Oxidative stress is considered to be involved in the pathophysiology of all cancers. The aim of this study is to examine oxidative stress and antioxidant status in patients with breast cancer by evaluation of the serum levels of total antioxidant capacity (TAC) and lipid peroxidation products as malondialdehyde (MDA) and lipid hydroperoxide and to investigate the relationship between these parameters, oxidative stress and serum lipids and lipoproteins. In our study, serum TAC, MDA, lipid hydroperoxide, HDL-cholesterol, VLDL-cholesterol, LDL-cholesterol, total cholesterol, triacylglycerol (TAG), albumin and uric acid levels of 56-breast cancer patients in different clinical stages and 18 healthy women were determined. Significantly lower-levels of TAC were detected in patients with breast cancer in comparison to controls (2.01 +/- 0.01 mmol/l and 2.07 +/- 0.03 mmol/l, respectively, p < 0.05). Serum MDA levels of the patients were higher compared to the controls (3.64 +/- 0.25 microM and 2.72 +/- 0.22 microM, respectively, p < 0.05). No significant difference between lipid hydroperoxide levels of patients and controls was found (0.33 +/- 0.05 microM and 0.32 +/- 0.01 microM, respectively, p > 0.05). These data show that lower TAC and higher MDA levels i.e. increased oxidative stress may be related to breast cancer.     

Booster irradiation to the spleen following total body irradiation. A new immunosuppressive approach for allogeneic bone marrow transplantation

Graft rejection presents a major obstacle for transplantation of T cell-depleted bone marrow in HLA-mismatched patients. In a primate model, after conditioning exactly as for leukemia patients, it was shown that over 99% of the residual host clonable T cells are concentrated in the spleen on day 5 after completion of cytoreduction. We have now corroborated these findings in a mouse model. After 9-Gy total body irradiation (TBI), the total number of Thy-1.2+ cells in the spleen reaches a peak between days 3 and 4 after TBI. The T cell population is composed of both L3T4 (helper) and Lyt-2 (suppressor) T cells, the former being the major subpopulation. Specific booster irradiation to the spleen (5 Gy twice) on days 2 and 4 after TBI greatly enhances production of donor-type chimera after transplantation of T cell-depleted allogeneic bone marrow. Similar enhancement can be achieved by splenectomy on day 3 or 4 after TBI but not if splenectomy is performed 1 day before TBI or 1 day after TBI, strengthening the hypothesis that, after lethal TBI in mice, the remaining host T cells migrate from the periphery to the spleen. These results suggest that a delayed booster irradiation to the spleen may be beneficial as an additional immunosuppressive agent in the conditioning of leukemia patients, in order to reduce the incidence of bone marrow allograft rejection.     

Consequences and treatment of ovarian failure after total body irradiation for leukaemia.

OBJECTIVE--To assess the incidence and severity of physical and psychosexual symptoms in young women due to ovarian failure caused by total body irradiation for leukaemia and the women''s response to hormone treatment. DESIGN--Postal questionnaire and interview. SETTING--Leukaemia unit of oncology hospital. PATIENTS--Consecutive series of 46 English speaking women who had developed ovarian failure after total body irradiation and bone marrow transplantation as treatment for leukaemia. RESULTS--Of the 36 responders, 33 reported some symptoms, vaginal dryness being the most common (29). This profoundly affected sexual function. Although 22 women had had sexual intercourse within six months after treatment, 16 were less interested in and 18 experienced difficulties with sexual intercourse. Anxieties about sterility, femininity, and appearance were common and reduced self confidence. Almost half reported that they had changed their social habits and restricted their social activities. Treatment seemed effective in abolishing symptoms in 24 women, but vaginal dryness remained a problem in three. Two women failed to respond and intercourse remained impossible. CONCLUSIONS--Such patients are vulnerable and access to gynaecologists and endocrinologists soon after treatment would be valuable. The optimal treatment regimen and the long term benefits of treatment have yet to be established.