title: Reference air kerma and kerma-area product as estimators of peak skin dose for fluoroscopically guided interventions.
abstract: OBJECTIVE
  To determine more accurate regression formulas for estimating peak skin dose (PSD) from reference air kerma (RAK) or kerma-area product (KAP).
  
  
  METHODS
  After grouping of the data from 21 procedures into 13 clinically similar groups, assessments were made of optimal clustering using the Bayesian information criterion to obtain the optimal linear regressions of (log-transformed) PSD vs RAK, PSD vs KAP, and PSD vs RAK and KAP.
  
  
  RESULTS
  Three clusters of clinical groups were optimal in regression of PSD vs RAK, seven clusters of clinical groups were optimal in regression of PSD vs KAP, and six clusters of clinical groups were optimal in regression of PSD vs RAK and K AP. Prediction of PSD using both RAK andKAP is significantly better than prediction of PSD with either RAK or KAP alone. The regression of PSD vs RAK provided better predictions of PSD than the regression of PSD vs KAP. The partial-pooling (clustered) method yields smaller mean squared errors compared with the complete-pooling method.
  
  
  CONCLUSIONS
  PSD distributions for interventional radiology procedures are log-normal. Estimates of PSD derived from RAK and KAP jointly are mos t accurate, followed closely byestimates derived from RAK alone. Estimates of PSD derived from KAP alone are the least accurate. Using a stochastic search approach, it is possible to cluster together certain dissimilar types of procedures to minimize the total error sum of squares.
authors.affiliation: Radiation Epidemiology Branch, National Cancer Institute, Division of Cancer Epidemiology and Genetics, Bethesda, Maryland 20852-7238, USA.
authors.forename: Deukwoo
authors.initials: D
authors.lastname: Kwon
authors.forename: Mark P
authors.initials: MP
authors.lastname: Little
authors.forename: Donald L
authors.initials: DL
authors.lastname: Miller
mesh_terms: D003198:Computer Simulation; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D038622:Internationality; D008954:Models, Biological; D011829:Radiation Dosage; D015641:Radiography, Interventional / Q000379:methods*; D011874:Radiometry / Q000379:methods*; D012016:Reference Values; D012879:Skin Physiological Phenomena