|Fig. 1: This figure shows an example of a Co-60 cancer treatment unit. (Courtesy of the NCI. Source: Wikimedia Commons.)|
Many advances have been made in the field of radiation therapy over the past few decades. Radiation therapy is typically done using a linear accelerator, which generates X-rays and high energy electrons. Linear accelerators are the common method of treating cancer, and developments have been made to ensure that the radiation is only applied to the diseased tissue. However, radiation using Co-60 gamma rays has also been investigated and tested as a way to treat cancer. 
In the beginning of the 20th century, doctors began exploring the use of radiation as a form of treatment for cancer. It was quickly discovered that without careful attention to dosages, radiation could not only cure cancer but also cause it. Furthermore, after the discovery of X-Rays in 1895 by Wilhelm Rontgen and Henri Becquerel, the doors were opened for radiotherapy to begin to be explored. However, as the harmful effects of radiation came to light, physicians and scientists took more cautious approaches to radiation, leaving gamma radiotherapy to fall slightly to the wayside.  Though it has been around for a long time, little research had been conducted to test the effectiveness of gamma radiation as a form of cancer therapy. One of the common methods of using gamma radiation for cancer treatment is the use of Co-60 radiation machines (Fig. 1).
Stereotactic radiosurgery is a process that involves treating a cancerous site such as the brain or heart with a linear accelerator or Gamma unit, a noninvasive device that uses gamma rays to treat the problem sites. 
In 2009, Schreiner et al. published a report on the role of Co-60 in the field of radiation therapy.  The experimental procedure used a Co-60 T780C, which is a commonly-used Cobalt-60 radiation treatment unit made by Canadian manufacturer Best Theratonics. First, imaging was done to see if the Cobalt unit could generate an optimized dose distribution for treatment. It was found that 87% of the treatment volume satisfied the criteria of a +/- 3% in dose in a 3 mm distance accuracy scale. 
Overall, Schreiner et al. concluded that using Co-60 for radiation therapy is a promising field and more investigation and development should be done to explore this field of treatment.  Although Cobalt is a riskier method of treatment because it is less easy to control the treatment patterns, it is a clinically viable option for treatment and should be looked into for further exploration and development.
© Diba Massihpour. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 L. J. Schreiner et al., "The Role of Cobalt-60 in Modern Radiation Therapy: Dose Delivery and Image Guidance," J. Med. Phys. 34, 133 (2009).
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