Dose reduction in chest CT examination.

Computed tomography (CT) examinations involve relatively high doses to patients. The objectives of this study were to optimise the radiation dose for patient during CT chest scan and to estimate the lifetime cancer risk. A total of 50 patients were studied: control group (A) (38 patients) and optimisation group (B) (12 patients). The optimisation protocol was based on CT pitch increment and lowering tube current. The mean volume CT dose index (CTDI vol) was 21.17 mGy and dose length product (DLP) was 839.0 mGy cm for Group A, and CTDI vol was 8.3 mGy and DLP was 339.7 for Group B. The overall cancer risk was estimated to be 8.0 and 3.0 cancer incidence per million for Groups A and B, respectively. The patient dose optimisation during CT chest was investigated. Lowering tube current and pitch increment achieved a radiation dose reduction of up to 60 % without compromising the diagnostic findings.

Embryo development and pregnancies from in-vitro matured and fertilized human oocytes.

There is an increasing interest in retrieving immature oocytes in the absence of or with limited gonadotrophin exposure, with the aim of maturing them in vitro for embryo transfer purposes. The aim of this report is to present our experience of fertilization, embryonic development and pregnancies from in-vitro maturation cycles. A total of 18 patients underwent 21 cycles in which an average of 8.1 immature oocytes was retrieved after limited exposure to human menopausal gonadotrophin (HMG) and no exposure to human chorionic gonadotrophin (HCG). In one cycle, no oocytes were recovered. The oocytes were cultured for 44 h and 121 oocytes which reached MII were injected with a single spermatozoon. A total of 71 oocytes showed two pronuclei and 53 zygotes cleaved. Forty-four embryos were transferred in 17 cycles. Five weeks after embryo transfer, ultrasound examination indicated the presence of one gestational sac and one fetal heart beat in two patients. The results suggest that in-vitro matured oocytes can undergo fertilization and the resulting embryos may result in pregnancies. However, the success rate was not sufficient to recommend widespread use of the technique without further research.

Effects of reducing insemination time in human in vitro fertilization and embryo development by using sibling oocytes.

PURPOSE: Recent studies showed a beneficial effect of reducing the time of sperm-oocyte interaction on fertilization, division, and implantation rates of the oocytes obtained from randomized patients. In the present study, the effects of reduced insemination time on fertilization and embryo development were evaluated by using sibling oocytes from the same patient. METHODS: A total of 464 oocytes from 36 patients was randomly allocated to be inseminated for either 1 hr (reduced) or 18 hr (regular). RESULTS: Fertilization rates were not significantly different between reduced (135/229; 59%) and regular (150/235; 64%) groups. Cleavage rates and embryo quality were similar in both groups. A total of 135 embryos (73 from the reduced and 62 from the regular group) was transferred to 36 patients. Thirty-four embryos implanted in 18 patients (25.2% implantation and 50.0% pregnancy rates). CONCLUSIONS: Fertilization, cleavage, and embryo development from 1-hr insemination is comparable, not superior, to those from an 18-hr insemination time, which is commonly used in in vitro fertilization programs. These data suggest that reduced insemination time can be used during in vitro fertilization to avoid unnecessarily longer exposure to spermatozoa.