It is often necessary to estimate the exposure rate at a distance from radionuclide emitting gamma or X rays. Such calculations may be required for planning radiation protection measures around radioactive sources, for calibration radiation monitoring instruments, for patient containing radionuclides or for estimating the absorbed dose to patients receiving brachytherapy. The factor relating activity and exposure rate has been various names: the k factor (Johns, 1961), the specific gamma ray constant (ICRU Rep. 10a, 1962), exposure rate constant (Parker et al., 1978) and gamma rate constant (Kereiakes & Rosenstein, 1980). Conversion to SI units required that this factor be replaced by the air kerma rate constant which is now defined as:  = 2 l A ( air dK dt )  (1)

Cardiovascular diseases (CVD) remain a major burden for public health worldwide. Pivotal concern of primary prevention is identification of individuals that are at risk for developing cardiovascular disease. The use of different algorithms for an assessment of cardiovascular risk allows physicians to identify and treat in a simple and cost-effective manner individuals that may be at high long-term cardiovascular risk.

Significant increase in noncommunicable diseases, in particular cardiovascular disease, in the past few decades worldwide represents one of the major health challenges in the overall global and social development of society. Cardiovascular conditions have the highest impact on lost years of life, lost quality of life, but also on the differences in longevity in different population groups. Global statistics show that cardiovascular conditions are responsible for one third of global deaths, while coronary heart conditions are the leading cause of death worldwide. (1,2) Many population research studies corroborated that high blood pressure is an independent and significant risk factor of cardiovascular disease and coronary heart disease and most significant determinant of morbidity and mortality in developed countries. (2,3)

Breast cancer is the most frequently diagnosed type of cancer nowadays and it is the leading cause of death caused by cancer in women (Jemal et al., 2011). It has become one of the main health problems both in developed and in developing countries. More than a million new cases of breast cancer are diagnosed every year all over the world (Ferlay et al., 2004). According to researches of the American Cancer Society (American Cancer Society, 2002), since 2002 breast cancer has been the second largest cause of death caused by cancer in women. According to a research conducted in 2007 in Korea, breast cancer was the second most frequently detected type of cancer in women (Kyu-Won et al., 2010). In 2008 there were 3, 2 million (Ferlay et al., 2010) new cases of cancer in Europe out of which 421, 000 (13,1%) (Ferlay et al., 2010) cases were breast cancers. According to the mentioned research, after colorectal cancer (436, 000 cases) breast cancer is the second most frequently registered cancer in Europe (Ferlay et al., 2010). In Bosnia and Herzegovina 1600 new cases of breast cancer are registered every year (Saric, 2009). Nowadays, mammography represents the best diagnostic way for detection of breast cancer. This diagnostic medical discipline applies a specially designed roentgen apparatus for breast examination. A good topographic position and a high degree of mobility of the breast (Fajdic, 2001) enable a great number of early diagnosed breast cancers detected with mammography. Ultrasound breast diagnostic is often used as an additional method to classic mammography for breast cancer detection, especially identification of cysts in the breast (Fajdic, 2001). Nowadays there are classic (film-screen) and digital mammography. While digital mammography enables a superior contrast resolution, its spatial resolution is somewhat lower in regard to the standard technique (Kuzmiak et al., 2005). Advantages and disadvantages of these two types of mammography were compared in more than ten studies (Rosselli Del Turco et al., 2007; Skaane, 2009). One of the main arguments for giving priority to digital mammography in regard to classic mammography was the fact that digital systems cause less radiation during an examination (Hermann et al., 2002; Moran et al., 2005). The newest study shows that digital mammography cannot guarantee significantly lower patient doses in regard to classic mammography (Hauge et al., 2011). The objective of most studies about mammography is to define benefits and risks caused by application of radiation in

Currently, the genus Malassezia includes 14 species, which have been identified traditionally based on their morphology and biochemical features (Cafarchia et al., 2011). Since the description of new species a number of studies have evolved to elucidate the role of the different species in the ecology and pathogenicity in a range of dermatoses, in which variable results have been reported from different geographical regions.