The researchers included Bijan Hashemi-Malayeri, a faculty member of the university, and Karim Khoshgard, the university's medical physics graduate.

The nanoparticles operate as a radiosensitizer to enhance the efficiency of radiotherapy by 60 percent by increasing the dose absorbed in tumor cells where they can accumulate.

A radiosensitizer is a drug that makes tumor cells more sensitive to radiation therapy.

Gold nanoparticles with an average diameter of 52 nm were synthesized and conjugated to folic acid molecules.

Folate-conjugated gold nanoparticles can significantly enhance the cell killing potential of orthovoltage X-ray energies in cancer cells in radiotherapy techniques.

Orthovoltage X-rays are produced by X-ray generators operating at voltages in the 200–500 kV range, and therefore energy in the 200–500 keV range. When used to treat patients, radiation oncologists find that they penetrate to a useful depth of about 4–6 cm.

That makes them good for treating skin, superficial tissues, and ribs, but not for deeper structures such as lungs or pelvic organs.

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