RESUMEN
The objective of this work was to evaluate radiation doses delivered to technologists engaged in different tasks involving positron emission tomography (PET) studies with FDG (fluorodeoxyglucose). This investigation was performed in two French nuclear medicine departments, which presented significant differences in their arrangements and radiation safety conditions. Both centers administered about 300 MBq per PET/CT study, although only one of them is a dedicated clinical PET center. Dose equivalent Hp(10) and skin dose Hp(0.07) were measured using Siemens electronic personnel dosimeters. For assessment dose absorbed by hands during drawing up of tracer and injection into the patient, a Polimaster wristwatch gamma dosimeter was employed. Absorbed dose and the time spent during each investigated task were recorded for a total of 180 whole-body PET studies. In this report, the methodology employed, the results and their radioprotection issues are presented as well as discussed.
O objetivo deste trabalho foi o de avaliar doses absorvidas por profissionais de saúde em diferentes tarefas relacionadas à tomografia por emissão de pósitrons com [18F]-FDG (fluordesoxiglicose). Esta pesquisa foi realizada em dois centros de medicina nuclear na França, os quais apresentavam diferenças significativas em sua organização e radioproteção. Esses centros aplicavam aproximadamente 300 MBq por exame PET/CT, embora apenas um deles correspondesse a um serviço de medicina nuclear dedicado a exames por PET. A dose equivalente (Hp(10)) e a dose na pele Hp(0,07) foram medidas usando dosímetros eletrônicos (Siemens). Para avaliação da dose nas mãos do tecnologista durante a preparação do radiofármaco e durante injeção no paciente, um dosímetro tipo relógio de pulso (Polimaster) foi empregado. A dose absorvida e o tempo empregado durante cada tarefa foram registrados para um total de 180 exames de corpo inteiro através da PET. Neste trabalho, a metodologia empregada, os resultados e suas conseqüências na dose absorvida para o profissional de saúde são apresentados e discutidos.
RESUMEN
French regulations have introduced the use of electronic dosimeters for personal monitoring of workers. In order to evaluate the exposure from diagnostic procedures to nuclear medicine staff, individual whole-body doses were measured daily with electronic (digital) personal dosimeters during 20 consecutive weeks and correlated with the work load of each day. Personal doses remained always below 20 æSv/d under normal working conditions. Radiation exposure levels were highest to tech staff, nurses and stretcher-bearers. The extrapolated annual cumulative doses for all staff remained less than 10 percent of the maximum legal limit for exposed workers (2 mSv/yr). Electronic dosimeters are not technically justified for routine survey of staff. The high sensitivity and immediate reading of electronic semiconductor dosimeters may become very useful for exposure control under risky working conditions. It may become an important help for optimising radiation protection
RESUMEN
The first study evaluating directly by the referring physician the clinical impact of [18F]-FDG-PET on modification of patient's management was performed only recently in California by means of a questionnaire. We have used the same methodology to evaluate this clinical impact during the opening year of our PET centre in France. A questionnaire was sent to the referring physician of each of the 476 patients who had at least one routine FDG-PET examination during the year 2000. Of 348 responses (response rate = 73%), the disease was upstaged in 26% of the cases and down-staged in 9%. Intermodality management changes (change from a scheduled therapeutic modality for a different one) were reported in 37% of the cases and intramodality changes in 9%. Those modification rates were respectively 38% and 7% in recurrence of colorectal cancer (153 patients), 47% and 7% in lung cancer (118 patients), 16% and 23% in lymphoma (43 patients), 25% and 6% in the staging of head and neck cancers (32 patients). When comparing with the corresponding studies performed in California, there were no significant differences between the rates of intermodality management changes. In contrast, intramodality management changes were less frequent in our survey, except for lymphoma. Globally, the clinical impact of FDG PET was similar with a higher response rate in our study (73% versus 35%); it was above the mean rate derived from a recent meta-analysis in more than 5,000 patients.