title: Determination of equivalent breast phantoms for different age groups of Taiwanese women: an experimental approach.
abstract: OBJECTIVE
  Polymethylmethacrylate (PMMA) slab is one of the mostly used phantoms for studying breast dosimetry in mammography. The purpose of this study was to evaluate the equivalence between exposure factors acquired from PMMA slabs and patient cases of different age groups of Taiwanese women in mammography.
  
  
  METHODS
  This study included 3910 craniocaudal screen/film mammograms on Taiwanese women acquired on one mammographic unit. The tube loading, compressed breast thickness (CBT), compression force, tube voltage, and target/filter combination for each mammogram were collected for all patients. The glandularity and the equivalent thickness of PMMA were determined for each breast using the exposure factors of the breast in combination with experimental measurements from breast-tissue-equivalent attenuation slabs. Equivalent thicknesses of PMMA to the breasts of Taiwanese women were then estimated.
  
  
  RESULTS
  The average +/- standard deviation CBT and breast glandularity in this study were 4.2 +/- 1.0 cm and 54% +/- 23%, respectively. The average equivalent PMMA thickness was 4.0 +/- 0.7 cm. PMMA slabs producing equivalent exposure factors as in the breasts of Taiwanese women were determined for the age groups 30-49 yr and 50-69 yr. For the 4-cm PMMA slab, the CBT and glandularity values of the equivalent breast were 4.1 cm and 65%, respectively, for the age group 30-49 yr and 4.4 cm and 44%, respectively, for the age group 50-69 yr.
  
  
  CONCLUSIONS
  The average thickness of PMMA slabs producing the same exposure factors as observed in a large group of Taiwanese women is less than that reported for American women. The results from this study can provide useful information for determining a suitable thickness of PMMA for mammographic dose survey in Taiwan. The equivalence of PMMA slabs and the breasts of Taiwanese women is provided to allow average glandular dose assessment in clinical practice.
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.
authors.forename: Shang-Lung
authors.initials: SL
authors.lastname: Dong
authors.forename: Tieh-Chi
authors.initials: TC
authors.lastname: Chu
authors.forename: Yung-Chien
authors.initials: YC
authors.lastname: Lin
authors.forename: Gong-Yau
authors.initials: GY
authors.lastname: Lan
authors.forename: Yu-Hsiu
authors.initials: YH
authors.lastname: Yeh
authors.forename: Sharon
authors.initials: S
authors.lastname: Chen
authors.forename: Keh-Shih
authors.initials: KS
authors.lastname: Chuanga
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D040761:Biomimetic Materials; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008875:Middle Aged; D019047:Phantoms, Imaging; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate