title: Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures.
abstract: OBJECTIVE
  The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures.
  
  
  METHODS
  The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit.
  
  
  RESULTS
  The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (± 1%), field size (± 1%), frame rate (± 3%), or beam energy (± 5%). The detector angular dependence was within ± 5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ± 3%.
  
  
  CONCLUSIONS
  The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.
authors.affiliation: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: M J
authors.initials: MJ
authors.lastname: Safari
authors.affiliation: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: J H D
authors.initials: JH
authors.lastname: Wong
authors.affiliation: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: K H
authors.initials: KH
authors.lastname: Ng
authors.affiliation: Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: W L
authors.initials: WL
authors.lastname: Jong
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: D L
authors.initials: DL
authors.lastname: Cutajar
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: A B
authors.initials: AB
authors.lastname: Rosenfeld
mesh_terms: D002138:Calibration; D004307:Dose-Response Relationship, Radiation; D005471:Fluoroscopy / Q000295:instrumentation / Q000379:methods; D006801:Humans; D016014:Linear Models; D019047:Phantoms, Imaging; D015642:Radiology, Interventional / Q000295:instrumentation* / Q000379:methods*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012867:Skin / Q000528:radiation effects*; D014867:Water
chemical_list: D014867:Water