Ultrashort Laser Pulses Reduce Off-Target Effects of Radiotherapy

Researchers from the Tata Institute of Fundamental Research in India have developed an innovative technique to cause DNA damage in a controlled manner. Short, intense pulses of laser light can be directed to a therapeutic target without damaging the surrounding area. The findings were published in the journal Scientific Reports.

Radiotherapy is a treatment that uses ionizing radiation against a target of interest, commonly cancer cells, to reduce the number -or contain the spread- of malignant cells. These radiations damage the DNA and lead to cell death. Some techniques diminish the amount of radiation received by healthy tissues: several beams can be directed to the tumor from different angles, concentrating the effect at the desired point while not affecting the healthy tissues to the same extent. However, it is always necessary to irradiate a portion of healthy tissue around the cancer cells, due to internal motion and other factors that make uncertain the exact position of the target.

A more precise delimitation of the irradiated area

The researchers at TIFR Mumbai decided to try the effect of high-intensity femtosecond laser pulses on DNA. The beams ionize the water molecules surrounding the DNA, giving rise to low energy electrons and OH radicals that generate DNA breaks. Professor Deepak Mathur’s team experimented with different conditions of laser energy and focusing, and concluded that the numerical aperture of the focusing lens delimitates two regimes of DNA damage. The discovery allows to fine-tune the extent of damage inflicted by just manipulating an optical parameter.

The ability of ultrashort laser pulses allow to confine the radiation to smaller areas (125 μm3) and thus reduce off-target effects might foster new clinical practices in cancer treatment.

Source: TIFR