High-dose-rate brachytherapy of rhabdomyosarcoma limited to the external auditory canal Journal Article
| Authors: | King, M. T.; Voros, L.; Cohen, G. N.; Lanning, R. M.; Ganly, I.; O'Suoji, C. C.; Wolden, S. L. |
| Article Title: | High-dose-rate brachytherapy of rhabdomyosarcoma limited to the external auditory canal |
| Abstract: | Purpose To report on the single-catheter high-dose-rate brachytherapy treatment of a 21-month-old girl child with an embryonal, botryoid-type, rhabdomyosarcoma limited to the external auditory canal (EAC). Methods and Materials A 2.4-mm diameter catheter was inserted into the right EAC and placed against the tympanic membrane. A computed tomography simulation scan was acquired. A brachytherapy treatment plan, in which 21 Gy in seven fractions was prescribed to a 1-mm depth along the distal 2 cm of the catheter, was generated. Treatments were delivered under anesthesia without complication. A dosimetric comparison between this plan and an intensity-modulated radiation therapy (IMRT) plan was then conducted. A clinical target volume (CTV), which encompassed a 1-mm margin along the distal 2 cm of the catheter, was delineated for both plans. Given positioning uncertainty under image guidance, a planning target volume (PTV = CTV + 3-mm margin) was defined for the IMRT plan. The IMRT plan was optimized for maximal CTV coverage but subsequently normalized to the same CTV volume receiving 100% of the prescription dose (V100) of the brachytherapy plan. Results The IMRT plan was normalized to the brachytherapy CTV V100 of 82.0%. The PTV V100 of this plan was 34.1%. The PTV exhibited dosimetric undercoverage within the middle ear and toward the external ear. Mean cochlea doses for the IMRT and brachytherapy plans were 26.7% and 10.5% of prescription, respectively. Conclusions For rhabdomyosarcomas limited to the EAC, a standard brachytherapy catheter can deliver a highly conformal radiation plan that can spare the nearby cochlea from excess radiation. © 2016 American Brachytherapy Society |
| Keywords: | rhabdomyosarcoma; pediatrics; high-dose rate; external auditory canal |
| Journal Title: | Brachytherapy |
| Volume: | 16 |
| Issue: | 1 |
| ISSN: | 1538-4721 |
| Publisher: | Elsevier Science, Inc. |
| Date Published: | 2017-01-01 |
| Start Page: | 181 |
| End Page: | 185 |
| Language: | English |
| DOI: | 10.1016/j.brachy.2016.07.003 |
| PROVIDER: | scopus |
| PMCID: | PMC5253256 |
| PUBMED: | 27528589 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 2 February 2017 -- Source: Scopus |
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