Doctors prepare a patient for treatment last week using a Linear Accelerator (Linac) machine at Texas Cancer Centre in Nairobi. PHOTO | SARAH OOKO
What you need to know:
Kenyatta National Hospital has been using a Cobalt-60 radiotherapy machine.
Private hospitals have embraced the digital Linear Accelerator Machine (Linac) which has gained popularity worldwide due to its advanced features.
Last week’s public uproar following revelations that two radiotherapy machines at Kenyatta National Hospital (KNH) had broken down brought to light various aspects of cancer care in Kenya.
Aside from the dire situation that the country currently faces due to inadequate cancer healthcare infrastructure, Kenyans also learned about available cancer treatment technologies in both the public and private sector.
It emerged that whereas KNH, the top public referral hospital in Kenya, was using a Cobalt-60 radiotherapy machine; their counterparts in the private sector had already embraced the digital Linear Accelerator Machine (Linac) which has gained popularity worldwide due to its advanced features.
However, the good news is that KNH plans to replace one of the damaged machines with a Linac one soon, thus enabling patients to benefit from the advanced technology.
With a cobalt machine, the radioactive element (cobalt) releases gamma rays which are used to destroy cancer cells. Since the rays are emitted as the cobalt gradually decays, the amount of radiation released decreases over time.
The radiation dose is high when the cobalt is ‘‘new’’, but as it ages the dose decreases.
Thus, if the machine initially offered radiotherapy treatment to patients for 20 minutes, doctors will gradually increase the duration so as to attain the required dose. Dr Catherine Nyongesa, a consultant radiation oncologist at KNH, noted that this contributes to the long queues at the facility.
Hospitals using this technology are required to change their radiation source (cobalt) after five years. The Linac machine, on the other hand, uses electricity to produce x-rays which destroy cancer cells.
The amount of radiation emitted by this machine is constant. “Patients take a shorter time during treatment, about 10 to 15 minutes,” said Dr Ahmed Komen, the Clinical and Radiation Oncologist at Aga Khan University Hospital (AKUH) which has been using the technology since setting up its cancer centre in 2011.
Since its energy levels are higher, the Linac machine is better suited for treating deep-seated cancerous tumours than the Cobalt one. It also has electron beams which enable doctors to adequately treat superficial tumours without harming organs such as the liver, lungs and kidneys.
The beams can be used to treat cancers found in various skin regions. It also treats tumours that affect limbs such as melanoma and lymphoma. Dr Komen noted that the high-tech Linac machines protect patients from adverse effects of radiation treatment.
The machine comes with software which allows doctors to map treatment areas on dummy ‘‘digital’’ patients as they develop treatment plans specific to various patients.
“From the computer we can tell exactly where the radiation will go and if we notice that it may affect certain body organs, we make adjustments accordingly,” he said.
This ensures that radiation is directed to the intended treatment site thereby minimising adverse risks to patients. Before radiotherapy machines are installed in a health facility, Dr Nyongesa said, a bunker is constructed. This acts as a shield which protects doctors and other medics from radiation emitted during treatment.
“Safety has to be guaranteed, it’s only patients who are exposed to radiation,” said Dr Nyongesa who is also the founder and director of Texas Cancer Centre in Nairobi which offers radiotherapy.
Before the treatment begins, radiation technologists prepare patients and adjust the Linac machine. They then operate the machine remotely, using computers located outside the room. With cameras installed in the radiation room, they are also able to observe patients and speak to them through a microphone.
Since the Linac technology uses electricity to produce x-ray beams, once the machine is switched off there is no radiation in the room.
But the cobalt machine keeps emitting radiation whether it is being used or not. Hospitals often avert risks by shielding the cobalt when the machine is off.
Used up cobalt can also pose environmental problems if disposed of incorrectly because is still releases radiation. Aside from cancer treatment, the Linac machine has other medical uses.
Its radiation can reverse the rejection of an organ transplant, suppress the immune system of patients undergoing blood and marrow transplants, and correct certain neurological and cardiovascular disorders.
Despite its challenges, the Cobalt machine is still effective in treating cancer. It is also prevalent in most developing nations due to its cheaper cost, reliability and ease of use.
Dr Nyongesa said that it also acts as a powerful pain killer for cancer patients and can stop bleeding in areas affected by the cancer. Cancer can also be treated through surgery and drugs (chemotherapy). But sometimes patients may require all the three types of treatment, especially if the disease is diagnosed late.
Apart from the Linac machine to be installed at KNH, the government has partnered with the World Bank to install eight more in hospitals across the country by September this year.
