title: A Patient-Specific Polylactic Acid Bolus Made by a 3D Printer for Breast Cancer Radiation Therapy.
abstract: OBJECTIVE
  The aim of this study was to assess the feasibility and advantages of a patient-specific breast bolus made using a 3D printer technique.
  
  
  METHODS
  We used the anthropomorphic female phantom with breast attachments, which volumes are 200, 300, 400, 500 and 650 cc. We simulated the treatment for a right breast patient using parallel opposed tangential fields. Treatment plans were used to investigate the effect of unwanted air gaps under bolus on the dose distribution of the whole breast. The commercial Super-Flex bolus and 3D-printed polylactic acid (PLA) bolus were applied to investigate the skin dose of the breast with the MOSFET measurement. Two boluses of 3 and 5 mm thicknesses were selected.
  
  
  RESULTS
  There was a good agreement between the dose distribution for a virtual bolus generated by the TPS and PLA bolus. The difference in dose distribution between the virtual bolus and Super-Flex bolus was significant within the bolus and breast due to unwanted air gaps. The average differences between calculated and measured doses in a 200 and 300 cc with PLA bolus were not significant, which were -0.7% and -0.6% for 3mm, and -1.1% and -1.1% for 5 mm, respectively. With the Super-Flex bolus, however, significant dose differences were observed (-5.1% and -3.2% for 3mm, and -6.3% and -4.2% for 5 mm).
  
  
  CONCLUSIONS
  The 3D-printed solid bolus can reduce the uncertainty of the daily setup and help to overcome the dose discrepancy by unwanted air gaps in the breast cancer radiation therapy.
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chang Heon
authors.initials: CH
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.|Center for Convergence Research on Robotics, Advance Institutes of Convergence Technology, Suwon, Republic of Korea.
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: MinSoo
authors.initials: M
authors.lastname: Chun
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.|Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jung-In
authors.initials: JI
authors.lastname: Kim
mesh_terms: D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D011091:Polyesters; D066330:Printing, Three-Dimensional; D011829:Radiation Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D012867:Skin / Q000528:radiation effects
chemical_list: D011091:Polyesters; C033616:poly(lactide)