title: Estimating the absorbed dose to critical organs during dual X-ray absorptiometry.
abstract: OBJECTIVE
  The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom.
  
  
  METHODS
  An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus.
  
  
  RESULTS
  There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 microGy and 1.81 microGy, respectively. Also, the scan center dose in the women was 5.70 microGy. There was correlation between the thyroid and uterus surface doses, and the scan center dose.
  
  
  CONCLUSIONS
  We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.
authors.affiliation: Department of Medical Physics, Tarbiat Modares University, Tehran, Iran. mokhtarm@modares.ac.ir
authors.forename: M
authors.initials: M
authors.lastname: Mokhtari-Dizaji
authors.forename: A A
authors.initials: AA
authors.lastname: Sharafi
authors.forename: B
authors.initials: B
authors.lastname: Larijani
authors.forename: N
authors.initials: N
authors.lastname: Mokhlesian
authors.forename: H
authors.initials: H
authors.lastname: Hasanzadeh
mesh_terms: D015502:Absorptiometry, Photon; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D013131:Spine / Q000000981:diagnostic imaging; D013961:Thyroid Gland / Q000528:radiation effects*; D014599:Uterus / Q000528:radiation effects*