Measurement of the Induced Radionuclides in Production of Radiopharmaceuticals for Positron Emission Tomography (PET)

Abstract

The radioactive by-products contained in an entire series of target foil, [ 18 O]H 2 O and synthesis apparatus were identified and quantified. From the perspective of waste management, 60 Co induced in Havar foil should be taken into consideration. Because the exempt activity of 60 Co in BSS is 0.1 MBq, the used Havar foil should be managed more than for 20 years. The radionuclides in the [ 18 F]-FDG synthesis apparatus are negligible. Equivalent doses at skin and to tissues were estimated assuming a point source at a distance of 30 cm in air. The annual equivalent doses at skin and equivalent dose at deep tissues of such an operating staff will be 56 and 8.3 mSv, respectively, as two times the remove of the target foil and five hundreds times the synthesis of the [ 18 F]-FDG. When proper radiation protection is provided, the exposure from the cyclotron management and the [ 18 F]-FDG synthesis process will not cause meaningful radiological risk to the operating staff. The activity concentration of 3 H, 180 kBqÁcm À3 , detected in the target water, is 3,000 times the legal limit of effluent for 3 H. The operators should take care of the treatment of the target water when they make a distillation for reuse and a disposal.

Evaluating air kerma at a medical cyclotron after refined shielding design using the TLD approach

“…The 'extra' photon radiation, however little, is a health concern for medical personnel and the public. Environmental radiation outside of the operating cyclotron, although low, cannot be ignored for the principles of ALARA [3,4,10].…”

“…The vault room is accessed from the maze directly through two motor-driven sliding doors, d 1 and d 2 , which are made of 1-cm-thick Pb and 5-cm-thick PE. The cyclotron's self-shielded system is a primary radiation shield that surrounds the RDS-111 cyclotron and ensures complete protection against and has reduced the mixed radiation (i.e., photons and neutrons) field to safe levels since 1998 [1][2][3][4]10,13]. A few high-energy photons from 511 keV of 18 F (either the 18 F radionuclide or 18 F-FDG radiopharmaceutical drugs) and activated materials from Havar foil, can penetrate the concrete shielding wall and further scatter around the vicinity of the cyclotron center [4].…”

“…Neutron production is through 18 O(p, γ n) 18 F. Many materials around the target are activated by stray neutrons [2,4]. The trenches under the vault floor provide a pathway to carry the 18 F delivery lines from the cyclotron targets into the hot cell (cf.…”

“…Rapid growth of positron emission tomography combined with computer tomography (PET/CT) as a clinical tool has rapidly increased the number of dedicated PET radiopharmaceutical production sites worldwide, especially in Taiwan [1][2][3][4][5]. Very few studies have measured air kerma, focusing rather on neutron dose [1,3,4,6,7].…”

“…Very few studies have measured air kerma, focusing rather on neutron dose [1,3,4,6,7]. The Republic of China (ROC), Taiwan, is an island country with a population of 23 million.…”