Current Status of the Study of 226Ra and 228Ra in Humans at the Center for Human Radiobiology

Determination of 226Ra in cheese produced in the rural area of Pernambuco-Brazil

“…For determining the bone sarcoma incidence rate, Rowland et al (1978) verified that Eq. 3 is the one that best describes the risk, considering a minimum latent period of 5 years.…”

“…According to Mays et al (1985), 20% of the total 226 Ra ingested by man is transferred to blood. To calculate the cranium carcinoma incidence rate resulting from 226 Ra presence in blood, Rowland et al (1978) considered a latent minimum period of 10 years. According to their studies, the curve that best describes the risk for induction of cranium carcinoma is given by Eq.…”

“…On the basis of a life expectancy of the 68.6 years for the population of the region studied (IBGE 2003), only the transference of 226 Ra during 58.6 years is considered effective for inducing cranium carcinoma, considering a minimum of 10 years latency, for appearance of these kinds of tumors (Rowland et al 1978).…”

“…In contrast, the normal risk estimate is 375 cases of carcinoma are expected per 10 6 persons per year (FUSAM 2002). In the determination of bone sarcoma accumulated risk, the total 226 Ra activity transferred to blood in the period of 63.6 years is about 3.0 · 10 3 Bq, for 5 years latency (Rowland et al 1978). Also using the accumulated risk value, the number of bone sarcoma cases in million people is 0.02 per year.…”

Radium-226 in Sugar Cane, Saccharum officinarum, Products in the State of Pernambuco, Brazil

“…Based on this, an estimate of the head carcinoma induction risk and bone sarcoma risk to the population of the study region for was calculated. Therefore, based on the life expectancy of the 68.6 years for the population of the study region (IBGE 2003), the transference of 226 Ra during 58.6 years would be sufficient to induce head carcinoma, allowing a minimum latent time of 10 years for the appearance of this kind of tumor (Rowland et al 1978). On the other hand, for the daily ingestion of 26.7 mBq and a period of 58.6 years, the activity ingested, due to 226 Ra during a lifetime would be approximately 5.7 9 10 5 mBq.…”