Trends in biological dosimetry: an overview

Dose assessment by quantification of chromosome aberrations and micronuclei in peripheral blood lymphocytes from patients exposed to gamma radiation

“…However, in most cases involving real or suspected accidental exposure, people are not wearing a dosimeter and, as a result, physical dosimetry is not straightforward. For such situations, the study of early biological effects induced by an exposure to IR has been proposed as either a complementary or an alternative method for dose assessment (Downing, 2000;Amaral, 2002;Bonassi and Au, 2002;Ramalho and Nascimento, 1991;Ramalho et al, 1995;Voisin et al, 2001).…”

“…Scoring of radio-induced CA from peripheral blood lymphocytes has been developed into a valuable dosimetric tool in radiological protection (IAEA, 2001). In particular, unstable CA (dicentrics, rings and fragments) are generally considered as specific to radiation exposure, and these types of aberrations are referred to as unstable CA because of their persistence in the body decline with cell division cycles (Amaral, 2002).…”

Biodosimetry for dose assessment of partial-body exposure: a methodological improvement

“…Hone et al (2005), for example, have shown that the dicentric yield remains constant up to 51 h, but rises by about 50% to a constant value beyond 60 h. The effect of culture time on aberration frequencies may be exacerbated in the situation of a partial-body exposure (Amaral, 2002). The irradiated fraction of cells may be selectively delayed in response to mitotic stimulation with PHA, slower progression around the cell cycle, or apoptotic elimination (Hoffmann et al, 2002;Hone et al, 2005).…”

“…For biodosimetry based on the scoring of chromosome aberrations (dicentrics, rings and fragments), it is important to consider only firstdivision (M1) lymphocytes. However, following partial-body irradiations, the irradiated fraction of cells may not have enough time to reach the first metaphase in traditional 48 h cell cultures because they may be selectively delayed or held for longer at check points during the cell cycle (Amaral, 2002;Hoffmann et al, 2002;Hone et al, 2005;Heimers et al, 2006). Irradiated cells may also be selectively removed by apoptosis.…”

Application of the laser radiation in patients of pressure ulcers: clinical and histomorphometric analysis of the derm

“…At the moment that such electrons occupy this orbits, suffer instability and fall spontaneously for levels of energy more low and with this energy liberates its extra in form of photons of light, whose energy characteristics will depend on the levels of energy that the excited electron fell, as well as the quantum energy inversely are related to the wave length. As cells and vessels in the organism it has different sensibility for the effect of the radioactive induction, the dose concept accomplishes was used taking in consideration all the cells radiated in detriment with the health (Amaral, 2002).The concept of absorbed dose has some limitations for evaluating biological effectiveness of exposure to radiation. On the other hand, effective dose was introduced to represent the long-term risk of harm of radiation exposure, in particular the risk of induced cancer by radiation (Amaral, 2002).The stimulated emission of the radiation occurs when an incident photon interacts with an atom that already is excited and its quantum energy must accurately be equal to the difference in the levels of rest and excited of the electron.…”