[Study of wedge factor dependence with depth, field size and SSD in [60] Co units]

In radiotherapy, wedge filters are used to modify iso-dose curves and hence optimize tumor dose distribution in patient. To deliver prescribed dose, timer or monitor unit should be involved the dose with no wedged field and wedge factor. Therefore, any variation of wedge factor due to treatment parameters will affect the deliver dose to patients. Effects of field size, SSD and depth of treatment on wedge factor were studied, using universal wedge filters with nominal angles of 30°, 45° and 60°, a hand made water phantom 21x21x10 Cm and a 0.6 cc Farmer ionizing chamber, at different SSD and depth from the water surface. Wedge factors were calculated as the ratio of charge [nC] of the wedge to open beam, measured by and an electrometer model NE2571, while the dosimeter was irradiated for 60s with Picker ATC9 [60]Co unit. Except for 60° wedge filter, with 95% certainty, there is no meaningful relation between wfs with field size and depth. For 60° wedge filter, variation of wf for situation used in this study is about 0.55% per Cm'Cm variation in field size and 0.28% per Cm variation in depth. An inverse linear relation between wf and SSD approved with 95% certainty. Variations of wf for 30°, 45° and 60° wedge filters, for situation used in this study are 0.11%, 0.18% and 0.33% per Cm variation in SSD respectively. Dependence of wfs to FS, depth and SSD for 60o wedge filter were formulated and shows that the field size and depth of treatment has a negligible effect on wedge factor. Correction of wf for SSD, which has a large domain of variation, is appreciable in clinical usage [more than 5%] and for 60o wedge filter can be calculated as: wfc=wf [1- 0.0033[SSD-80]] 65

[ effect of active and passive smoking associated with breast cancer]

Breast cancer is the most common cancer among women worldwide and continues to be a major cause of cancer death. Major risk factors for breast cancer studied for many years, but epidemiologic studies have been inconsistent in suggesting all association between smoking and breast cancer risk. The aim of this study was to evaluate the effect of active and passive smoking on breast cancer. In this case- control study, 105 patients with confirmed breast cancer referred to Omid hospital in Mashhad and were compared with 105 healthy women who were living in their neighborhood and were the age-matched [ +/- 3 years] with case group. Information concerning potential risk factors exposure status was collected by structured questionnaire and interview. Breast cancer risk relation to smoking was estimated by calculating the odds rations. In this study, smoking had no relation with breast cancer. Passive smokers had an odds ratio 18.5 [95% CI= 8.7-39.4]. The women used water pipe had an odds ratio 7.3 [95% CI= 2.7-19.7]. Also, in people who were passive smokers during their childhood, the odds were 4.86 fold. The findings suggested that the risk of breast cancer has a positive relationship with active and passive smoking and water pipe use. Thus, health interventions including no exposure to smoking and not use water pipe seem to be necessary in this regard

Association between reproductive factors with breast Cancer risk

Introduction: Breast cancer is a worldwide burden in both developed and develop: countries and unless some action is taken, it will continue to grow for the foreseeable futi Hence, diagnosing its risk factors is of great importance

The aim of this study was to investigate the association between menstrual and reproductive fact with breast cancer

Material and Methods: In a case-control study in Mashad loss patients with confirmed bre; cancer were compared with loss healthy women who were patient s neighborhood and matched cases by age and interview. A questionnaire including demographic information as well questions regarding reproductive factors emphasizing abortion were used. Data collect we analyzed using SPSS ver 12

Results: The findings indicated Early age at menarche, age at menopause, late age at first f term pregnancy and fewer number of full term pregnancy significantly associated with breast cam risk

The risk of breast cancer showed an increase in women who had a history of aborti [OR=2.09%95 C1M.2-3.7]. Also women experiencing abortion before their first full te pregnancy showed a higher risk of breast cancer [OR= 5.9 95% CI= 1.8-19.6]

Conclusion: Our findings suggest that decreased parity, early Age at menarche, late age menopause and first birth and abortion were the most important determinants of breast cancer thus authors purpose health interventions about these mothers