title: Radiation dose reduction in intra-arterial chemotherapy infusion for intraocular retinoblastoma.
abstract: OBJECTIVE
  Retinoblastoma (RB) is a rare malignancy affecting the pediatric population. Intravenous chemotherapy is the longstanding delivery method, although intra-arterial (IA) chemotherapy is gaining popularity given the reduced side effects compared with systemic chemotherapy administration. Given the sensitivity of the target organ, patient age, and secondary tumor susceptibility, a premium has been placed on minimizing procedural related radiation exposure.
  
  
  METHODS
  To reduce patient x-ray dose during the IA infusion procedure, customized surgical methods and fluoroscopic techniques were employed. The routine fluoroscopic settings were changed from the standard 7.5 pulses/s and dose level to the detector of 36 nGy/pulse, to a pulse rate of 4 pulses/s and detector dose to 23 nGy/pulse. The angiographic dose indicators (reference point air kerma (Ka) and fluoroscopy time) for a cohort of 10 consecutive patients (12 eyes, 30 infusions) were analyzed. An additional four cases (five eyes, five infusions) were analyzed using dosimeters placed at anatomic locations to reflect scalp, eye, and thyroid dose.
  
  
  RESULTS
  The mean Ka per treated eye was 20.1±11.9 mGy with a mean fluoroscopic time of 8.5±4.6 min. Dosimetric measurements demonstrated minimal dose to the lens (0.18±0.10 mGy). Measured entrance skin doses varied from 0.7 to 7.0 mGy and were 73.4±19.7% less than the indicated Ka value.
  
  
  CONCLUSIONS
  Ophthalmic arterial melphalan infusion is a safe and effective means to treat RB. Modification to contemporary fluoroscopic systems combined with parsimonious fluoroscopy can minimize radiation exposure.
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Cooke
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Stout
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Warren T
authors.initials: WT
authors.lastname: Kim
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hetts
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Randall T
authors.initials: RT
authors.lastname: Higashida
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Van V
authors.initials: VV
authors.lastname: Halbach
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Dowd
authors.affiliation: Department of Radiology and Biomedical Imaging, University California San Francisco, San Francisco, California, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gould
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage / Q000627:therapeutic use; D003131:Combined Modality Therapy; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007223:Infant; D007261:Infusions, Intra-Arterial; D008297:Male; D008558:Melphalan / Q000008:administration & dosage / Q000627:therapeutic use; D011829:Radiation Dosage; D019572:Retinal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D012175:Retinoblastoma / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D008558:Melphalan
keywords: Intervention; Orbit; Pediatrics; Technique; Tumor