title: Radiation dose in repeated CT guided radiofrequency ablations.
abstract: OBJECTIVE
  To calculate the cumulative effective and skin doses in patients that underwent repeated CT guided radiofrequency ablations (RFA).
  
  
  METHODS
  From all patients that had undergone RFA during a five years period those which had three or more RFAs were selected. Using the CT images DICOM data, the dose length product (DLP), effective dose (E), skin dose profiles as well as the peak skin dose (PSD) were calculated, using appropriate methods and software developed for this purpose. For each patient, cumulative DLP and E were also calculated from the sum of the respective figures of each individual procedure. To calculate PSD, the skin dose profiles of each procedure were overlaid on the same Z-axis scale using anatomical landmarks for reference and the skin doses to each point were summed up.
  
  
  RESULTS
  Five patients were studied; four had undergone 3 RFAs and one 10 RFAs. Cumulative DLP, E and PSD ranges were 5.6-22.3 Gy cm, 0.08-0.36 Sv and 0.8-3.4 Gy, respectively. Median E and PSD values per RFA were 35 mSv and 0.4 Gy, respectively. For comparison purposes it must be noted that in this CT department a routine abdomen-pelvis scan results to an E of about 10 mSv.
  
  
  CONCLUSIONS
  Patients that undergo repeated RFAs are exposed to considerably high radiation exposure levels. When these patients are in the final stage of malignant diseases, stochastic effects may not be of major concern. However, optimization of the exposure factors and monitoring of these patients to avoid skin injuries are required.
authors.affiliation: Medical Physics Unit, Konstantopoulio Hospital, Agias Olgas 3-5, 142 33 Nea Ionia, Athens, Greece.
authors.forename: V
authors.initials: V
authors.lastname: Tsapaki
authors.affiliation: Medical Physics Dpt, Agios Savvas Hospital, 171 Alexandras Avenue, 115 22 Athens, Greece. Electronic address: j_tsalas@hotmail.com.
authors.forename: I A
authors.initials: IA
authors.lastname: Tsalafoutas
authors.affiliation: CT Department, Konstantopoulio Hospital, Agias Olgas 3-5, 142 33 Nea Ionia, Athens, Greece.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Triantopoulou
authors.affiliation: CT Department, Konstantopoulio Hospital, Agias Olgas 3-5, 142 33 Nea Ionia, Athens, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Kolliakou
authors.affiliation: CT Department, Konstantopoulio Hospital, Agias Olgas 3-5, 142 33 Nea Ionia, Athens, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Maniatis
authors.affiliation: CT Department, Konstantopoulio Hospital, Agias Olgas 3-5, 142 33 Nea Ionia, Athens, Greece.
authors.forename: J
authors.initials: J
authors.lastname: Papailiou
mesh_terms: D055011:Ablation Techniques / Q000379:methods*; D000368:Aged; D006801:Humans; D008875:Middle Aged; D011829:Radiation Dosage; D000078702:Radiofrequency Therapy; D012867:Skin / Q000000981:diagnostic imaging / Q000528:radiation effects; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed
keywords: CT-guided radiofrequency ablation; Effective dose; Patient dose; Skin dose