• D.E. Donets, E.D. Donets, E. E. Donets, V.V. Salnikov, V. B. Shutov, E. M. Syresin
  JINR, Dubna

Accelerated ¹²C ion beams are effectively used for cancer treatment at various medical centers, in particular to treat patients with radio resistant tumors. On the other hand, positron emission tomography is the most effective way of tumor diagnostics. The intensive ¹¹C ion beam could allow both these advantages to be combined. It could be used both for cancer treatment and for on-line positron emission tomography. Formation of a primary radioactive ¹¹C⁶⁺ ion beam with the intensity of 10¹⁰-10¹¹ pps from the ion source may allow cancer treatment and on-line dose verification. ¹¹C isotope is produced in the nuclear reaction ¹⁴N (p,α)¹¹C using the gas target chamber irradiated by a proton beam. If the nitrogen target chamber contains about 5% of hydrogen, approximately 10¹⁴ methane molecules ¹¹CH₄ can be produced each 20 minutes. The separated radioactive methane can be loaded into an ion source. The methodology and technique of formation of high-intensity radioactive carbon beams were tested in the JINR electron string ion source (ESIS) Krion-2 using usual non radioactive methane. The measured conversion efficiency of methane molecules to carbon ions appeared to be rather high, 15 % for C⁶⁺ ions and 25% for C⁴⁺ ions. The developed technique of pulsed methane loading and the experimentally obtained conversion efficiency permit obtaining primary radioactive ¹¹C⁶⁺ beams at the intensity of 10¹⁰ -10¹¹ pps and performing cancer treatment and online dose verification.