New machine radiates hope for cancer patients
The Prince of Wales Hospital in Sha Tin has launched a new radiotherapy system that treats cancerous tumours faster and better.
The machine detects the motion of patients' tumours and directs radiation at them only when they are within an appropriate range.
Traditional radiotherapy systems draw out larger target zones for moving tumours so as not to miss them, but this often results in more nasty side effects for patients.
"The new machine shoots radiation only when the tumour gets into the target zone. It goes off when the tumour falls out of it," Dr Michael Kam Koon-ming, the hospital's clinical oncology consultant, said yesterday.
This ability would minimise the side effects in lung and liver cancer patients whose tumours shifted as they breathed, Kam said, so some people who were previously unsuitable for treatment could now receive it.
"Radiotherapy is highly damaging. In the past, radiation fell on too wide an area that should not have been targeted," said Professor Anthony Chan Tak-cheung, chairman of Chinese University's clinical oncology department.
The speed and accuracy of the new system made it feasible to use radiation dosages four times higher than those used with traditional machines, Kam said.
He took for example a lung cancer patient who would have needed 30 two-minute radiotherapy sessions over 30 days with the old machines. But with the new one, treatment would take just three five-minute sessions over three days, he said.
Lung and liver cancer patients found suitable for radiotherapy get priority to use the new system, which cost HK$40 million - about twice that of the hospital's traditional machines.