title: Dose calibrator linearity test: (99m)Tc versus (18)F radioisotopes.
abstract: OBJECTIVE
  The present study was aimed at evaluating the viability of replacing (18)F with (99m)Tc in dose calibrator linearity testing.
  
  
  METHODS
  The test was performed with sources of (99m)Tc (62 GBq) and (18)F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical (99m)Tc and (18)F sources activities were calculated and subsequently compared.
  
  
  RESULTS
  Mean deviations between experimental and theoretical (99m)Tc and (18)F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the (99m)Tc source as measured with the equipment pre-calibrated to measure (99m)Tc and (18)F was 3.42 (± 0.06), and for the (18)F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time.
  
  
  CONCLUSIONS
  The results of the linearity test using (99m)Tc were compatible with those obtained with the (18)F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in (18)F acquisition suggest (99m)Tc as the element of choice to perform dose calibrator linearity tests in centers that use (18)F, without any detriment to the procedure as well as to the quality of the nuclear medicine service.
authors: PhD, Head Physicist at the Service of Nuclear Medicine of Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (Icesp), São Paulo, SP, Brazil.
authors: José
authors: J
authors: Willegaignon
authors: Private Docent, Professor, Department of Radiology and Oncology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil.
authors: Marcelo Tatit
authors: MT
authors: Sapienza
authors: MD, Physician Assistant at the Service of Nuclear Medicine of Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (Icesp), São Paulo, SP, Brazil.
authors: George Barberio
authors: GB
authors: Coura-Filho
authors: Physicist at the Service of Nuclear Medicine of Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (Icesp), São Paulo, SP, Brazil.
authors: Alexandre Teles
authors: AT
authors: Garcez
authors: Master, Technologist, Comissão Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ, Brazil.
authors: Carlos Eduardo Gonzalez Ribeiro
authors: CE
authors: Alves
authors: PhD, Technologist, Comissão Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ, Brazil.
authors: Marissa Anabel Rivera
authors: MA
authors: Cardona
authors: PhD, Department Head, Comissão Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ, Brazil.
authors: Ricardo Fraga
authors: RF
authors: Gutterres
authors: Private Docent, Full Professor, Department of Radiology and Oncology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil.
authors: Carlos Alberto
authors: CA
authors: Buchpiguel
keywords: Dose calibrator; Linearity test; Nuclear instrumentation; Nuclear medicine