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Thomas B. Borak
Projects

Thomas.Borak@colostate.edu
Office: 337 Molecular and Radiological Biosciences Building

 


Skin Cancer Project

Comparing the risks for skin cancer and lung cancer from 222Rn decay products.

There has been a suggestion that ambient conditions in underground mines might cause cancers at sites other than the lung. Specifically, it was suggested that radon daughters in the ambient air might be responsible for an excess risk of skin cancer. This project determined the dose and risk to basal cells in the epidermis from plate-out of Rn daughters on the skin as a function of Working Level Month (WLM). This is then compared to the projected risk of lung cancer per WLM. Fig.1 is the depth dose distribution for alpha particle emitters uniformly deposited on a surface. Fig.2 is the distribution of basal cells as a function of depth below the surface of the skin. Click here to view the figures.
Combining these results and with plate out characteristics of 218Po and 214Po and including attenuation from moisture and dust on the surface of the skin, we obtain a result of 16 mSv/ WLM for the effective dose. The lifetime risk of fatal skin cancer following whole body exposure to the skin is 2x10-4 /Sv [ICRP 60 p 139]. The risk from radon decay products deposited on the skim would be approximately 3x10-6/WLM. The lifetime risk for lung cancer from inhalation of radon daughters is 2x10-4/WLM [ICRP 60 p 139]. From this dosimetric analysis, the risk of skin cancer is more than 60 times smaller that the risk of lung cancer for the same exposure to radon daughters.

Research Project 1 - Microdosimetry of high energy heavy particles.

This research, sponsored by NASA, is related to dosimetry of cosmic radiation during manned space missions. We are measuring the response of tissue equivalent proportional counters (TEPC) to beams of particles such as 56Fe, 18Si, 12C, 4He, and high energy neutrons that are produced at the NASA Space Radiation Laboratory in Brookhaven National Laboratory and the Heavy Ion Medical Accelerator at the National Institute of Radiological Sciences (NIRS) in Japan. This work is in collaboration with physicists from the Lawrence Berkeley National Laboratory and NIRS.

Fig. 1 shows the arrangement used during a recent experiment at HIMAC.
The arrangement used during a recent experiment at HIMAC

Mailing Address

Environmental & Radiological Health Sciences
1681Campus Delivery
Colorado State University
Fort Collins, CO 80523
Phone: (970) 491-7038
Fax: (970) 491-2940
Email: ERHSDepartment