Tens of thousands of cancer patients are missing out on potentially curative radiotherapy, it has been claimed.
Experts believe 52% of UK cancer patients are suitable for "radical" radiation treatment aimed at eradicating their disease but only around 40% of them actually receive radiotherapy.
The shortfall means an estimated 30,000 patients a year are losing a vital opportunity to be cured.
Ignorance and fear are two reasons why the take-up of radiotherapy is not higher, according to a group of organisations trying to improve public awareness and access to treatments.
The National Radiotherapy Awareness Initiative - whose members include charities, specialist professional bodies and the NHS - has launched a campaign marking the start of the Year of Radiotherapy, a century after Marie Curie won a second Nobel Prize for her work on the radioactive element radium.
Results of a survey released as part of the campaign show that fewer than 10% of those polled regarded radiotherapy as a "modern, cutting edge cancer treatment".
Just 15% of the 2,000 UK adults taking part thought of the treatment as "precise" and 40% described it as "frightening".
In reality, radiotherapy cured more patients than chemotherapy and technological improvements now make it possible to target tumours with millimetre accuracy, said the experts.
Side effects were often so mild that patients could continue working throughout their course of treatment.
Newer and even more precise techniques are now being introduced such as intensity modulated radiotherapy, which allows radiation beams to "bend" around tumours.