title: Individualised dosimetry in patients with differentiated thyroid cancer based on external dose-rate. Optimisation of the number of measurements.
abstract: OBJECTIVE
  To compare the results of individual dosimetry in differentiated thyroid cancer patients treated with (131)I at our centre with the established limits and dosimetry results of published studies. Analysis of the optimal number of measurements necessary to reduce the impact of dosimetry for the comfort of the patient and, secondly, on the workload of health workers.
  
  
  METHODS
  Dosimetry was performed in the Nuclear Medicine Department of the University and Polytechnic Hospital La Fe, on 29 patients suffering from differentiated thyroid cancer and treated with activities between 1.02 and 5.51 GBq (mean 2.68 GBq) of (131)I. The Spanish Society of Medical Physics (SEFM) protocol was used, based on measurements of external dose rate adjusted to a bi-exponential curve according to a two compartment model. Different dosimetries were performed on each patient, taking different selections of the available measurements in order to find the optimal number.
  
  
  RESULTS
  Results are well below the dosimetry limits, and are consistent with those obtained in other centres. The number of measurements can be reduced from 5, as proposed in the SEFM protocol, to 4 without significant loss of accuracy. Further reducing measures may be justified in individual cases.
  
  
  CONCLUSIONS
  The values obtained for the dosimetry quantities are significantly below the established limits. A reduction in measurements can be assumed at the cost of a moderate increase in uncertainty, benefiting the patient.
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario y Politécnico La Fe, Valencia, España. Electronic address: juananbau@gmail.com.
authors.forename: J A
authors.initials: JA
authors.lastname: Bautista-Ballesteros
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: I
authors.initials: I
authors.lastname: Torres-Espallardo
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: P
authors.initials: P
authors.lastname: Borrelli
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: A
authors.initials: A
authors.lastname: Rivas-Sanchez
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: P
authors.initials: P
authors.lastname: Bello
authors.affiliation: Servicio de Radiología, Hospital Universitario y Politécnico La Fe, Valencia, España; Grupo de Investigación Biomédica (GIBI2(30)), Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: L
authors.initials: L
authors.lastname: Martí-Bonmatí
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D013964:Thyroid Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes
keywords: (131)I; Cáncer diferenciado de tiroides; Differentiated thyroid carcinoma; Dosimetría individualizada; Individualised dosimetry; Metabolic therapy; Terapia metabólica