Preventing radiation in cancer therapies to damage healthy organs

The physicist specializing in radiation dosimetry of the Institute of Physics of the UNAM, said that ionizing radiation is used in the diagnosis and treatment of cancer.

"In extreme cases, if the dose is too high radiation can modify the cellular structure and generate alteration in the cells of organs found near the tumor, this causes them to lose their functions," said Massillon, who was honored for her research with the IUPAP Young Scientist Prize 2015 awarded by the International Union of Pure and Applied Physics.

The intention of the study is to analyze the interaction of ionizing radiation with matter and know how much energy the patient receives. The doctor explained that there are two types of radiation: ionizing and non-ionizing.

Non-ionizing radiation is in lasers, light beams and waves that are used to make ultrasound or magnetic resonance imaging. They have a longer wavelength, thus the power is low and does not change the structure of matter.

On the other hand, ionizing radiation such as x-rays and the used in CT scans or gamma-ray Mammograms do have enough power to change matter, because the wavelength is low and of high energy.

For example techniques with x-ray equipment are used for the early detection of breast cancer. To avoid affecting the patient, it is necessary to record and know how much radiation dose they received, and this is achieved with the use of thermoluminescent dosimeters.

These small crystals are materials capable of conserving energy when exposed to radiation, which on heating show the amount of energy deposited in the form of light.

The doctor said that to prove a mammography equipment the thermoluminescent dosimeter is placed in front of the machine (replacing the patient) and the necessary shots are taken. Later, the relationship between the light emitted by the crystal and the deposited energy in analyzed, so that the precise dose the patient will receive is known.

Another example is radiotherapy, used in the treatment of different cancers. In the case of the prostate, usually a radioactive seed is inserted into the patient and it goes directly to the tumor.

"Around the prostate are other healthy organs that are very sensitive, if the spatial distribution is known, most of the dose will stay in the sick area and the surrounding tissue is barely affected."

To reach this level, it is necessary to know how a dosimeter will respond to different types of radiation and the optimal conditions for usage.

Guerda Massillon, originally from Haiti but with a Mexican citizenship, was also selected as one of the Research Fellows by the Royal Society of London to develop her research project.

"When I work is not for a prize, but for a passion, to understand things, be useful to society. The awards are an honor, they tell you are on the right track, but at the same time they are a compromise. " (Agencia ID)