Pralay Singa Roy, 76, had been getting radiation therapy to treat his prostate cancer for five years at Apollo Hospitals in Chennai.

"I was given radiation through my rectum, which was not just uncomfortable, but also very undignified. I received 37 days' radiation therapy over many months," said the Kolkata-resident, who ends up spending eight months each year in Chennai with his son, an engineer with the Bhabha Atomic Research Center.

When Singa Roy became unwell again this summer, he visited Apollo for a follow-up. His doctor offered him the option of getting treated by the newly installed CyberKnife, an image-guided robotic radio-surgical device that he said targeted tumors with sub-millimeter accuracy.

Singa Roy agreed, and is now happy that he did. "CyberKnife treatment was incredible.

I was treated for six days, from July 16 to July 22, and I immediately felt better. I did not even feel unwell after treatment, as it happens after radiation therapy," said Singa Roy, who is currently in Kolkata to spend the Puja holidays with his wife.

What Singa Roy did not know is that he was being treated with a device that used cruise missile technology to target the cancer affected prostate gland that was making him sick. "It is similar to the GammaKnife as both use radiation to attack the cancer, but the technology is very different.

CyberKnife uses an image-guided cruise missile technology that cross-fires beams with the help of a robot to any part of the body, reaching areas that so far could not be reached using conventional radio-surgery," said Dr John R. Adler, creator of CyberKnife and a professor of neurosurgery and radiation oncology at Stanford University Medical Center, US. The flexibility and the precision of CyberKnife allow radio-surgeons to deliver high doses of radiation to tumors and lesions deep within the body without damaging the surrounding healthy tissue and organs. "The extremely precise dose of radiation delivered prevents damage to the surrounding healthy tissue, with the robot adjusting for movement - such as that caused by breathing - during treatment," said Dr Adler.

"Unlike the gammaKnife which is used for brain tumors, the CyberKnife can be used to treat cancers of the brain, spine, pancreas, liver, prostate, kidneys and lung, as well as other malformations and benign tumors," said Dr Adler, who in 1999 invented the first prototype of CyberKnife, advanced forms of which are now being used in 17 countries. As the technology evolves, he hoped to use for treating other disorders, such as depression and atrial fibrillation (abnormal heart rhythm), which is one of the leading cause of stroke.

The technology is particularly effective in treating prostate, lung and brain cancers, which are among the top five cancers in men in India. Increased accuracy and better access shortens the duration of treatment from the conventional six to eight weeks of radiation therapy to one week.

What patients welcome the most is the comparative comfort of getting treated. "Most high-precision radiation techniques require some form of sedation or a frame around the skull or patient's body.

What I liked best was that all I did was lie down for two hours at a stretch and leave for home," said Singa Roy. "Two of my patients at Stanford cycle to get treated and then bike back home two hours later," said Dr Adler, who surfs in California to relax.

There are 10 lakh (one million) new cancer cases in India every year, with the numbers projected to rise five-fold - 2.8 times because of tobacco use and 2.2 due to ageing - by 2025. Cancer kills 50 people in India every hour, making it the fourth biggest killer disease after heart disease, respiratory diseases and diarrhoea.

Since India's first CyberKnife was installed at Chennai's Apollo Hospitals in April this year, it has been used to treat 121 people, of whom 29 are from overseas. "Apollo Chennai offers complete treatment for $10,000 (Rs 4.8 lakh), which is a fraction of the costs in the US - anything between $50,000 and $60,000 (Rs 24 lakh to Rs 27.6 lakh)," said Dr Prathap Reddy, chairman, Apollo Hospitals.

Apollo plans to install CyberKnife in Delhi within six months. India's second CyberKnife was installed in HCG (Health Care Global), Bangalore, in May.

But what happens to patients who cannot afford treatment? "For high-end procedures such as CyberKnife, patients have the option of paying in monthly installments. This makes high-end care more accessible to the middle classes," said Dr B S Ajai Kumar, chairman and chief executive officer of HCG, which runs 18 cancer treatment centers in India.

HCG will bring CyberKnife to Delhi, Mumbai and Kolkata within a year. "I like using the cellphone analogy for India, where the masses got connectivity without going through infrastructure quagmire of landlines.

India can similarly bypass the mistakes made in the West that drove up cost. "India has the numbers and that can drive the price down," said Dr Adler.