Publications by authors named "Clayton Akazawa"

Purpose: To compare dose-volume histograms of target volumes and organs at risk in 57 patients with nasopharyngeal carcinoma (NPC) with inverse- (IP) or forward-planned (FP) intensity-modulated radiation treatment (IMRT).

Methods And Materials: The DVHs of 57 patients with NPC with IMRT with or without chemotherapy were reviewed. Thirty-one patients underwent IP IMRT, and 26 patients underwent FP IMRT.

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The first aim of the present study was to investigate the feasibility of using fewer beam angles to improve delivery efficiency for the treatment of oropharyngeal cancer (OPC) with inverse-planned intensity-modulated radiation therapy (IP-IMRT). A secondary aim was to evaluate whether the simplified IP-IMRT plans could reduce the indirect radiation dose. The treatment plans for 5 consecutive OPC patients previously treated with a forward-planned IMRT (FP-IMRT) technique were selected as benchmarks for this study.

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Purpose: To compare clinical outcomes of patients with carcinomas of the paranasal sinuses and nasal cavity according to decade of radiation treatment.

Methods And Materials: Between 1960 and 2005, 127 patients with sinonasal carcinoma underwent radiotherapy with planning and delivery techniques available at the time of treatment. Fifty-nine patients were treated by conventional radiotherapy; 45 patients by three-dimensional conformal radiotherapy; and 23 patients by intensity-modulated radiotherapy.

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Purpose: The aim of this study was to quantify gains in lymph node coverage and critical structure dose reduction for whole-pelvis (WP) and extended-field (EF) radiotherapy in prostate cancer using intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3DCRT) for the first treatment phase of 45 Gy in the concurrent treatment of lymph nodes and prostate.

Methods And Materials: From January to August 2005, 35 patients with localized prostate cancer were treated with pelvic IMRT; 7 had nodes defined up to L5-S1 (Group 1), and 28 had nodes defined above L5-S1 (Group 2). Each patient had 2 plans retrospectively generated: 1 WP 3DCRT plan using bony landmarks, and 1 EF 3DCRT plan to cover the vascular defined volumes.

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Purpose: To describe in detail a forward-planned multisegment technique (FPMS) as an alternative treatment method for patients who are not suitable for inverse-planned intensity-modulated radiation therapy (IP-IMRT), or for situations where IP-IMRT is not available in a medical clinic.

Methods And Materials: Between April 1995 and February 2002, 38 primary head-and-neck patients were treated using the FPMS technique, which has evolved over the past 7 years at our medical center. In the most recent version of the FPMS technique, which includes 5 patients examined in this analysis, the primary tumor and the upper neck nodes were treated with 7 gantry angles, including an anterior, 2 lateral, 2 anterior oblique, and 2 posterior oblique beams with a total of 13 beam shapes formed by multileaf collimators (MLC), called MLC segments.

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Purpose: To review the University of California-San Francisco (UCSF) experience of using intensity-modulated radiation therapy (IMRT) to treat head-and-neck cancer focusing on the importance of target volume delineation and adequate target volume coverage.

Methods And Materials: Between April 1995 and January 2002, 150 histologically confirmed patients underwent IMRT for their head-and-neck cancer at our institution. Sites included were nasopharynx 86, oropharynx 22, paranasal sinus 22, thyroid 6, oral tongue 3, nasal cavity 2, salivary 2, larynx 2, hypopharynx 1, lacrimal gland 1, skin 1, temporal bone 1, and trachea 1.

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Purpose: To compare intensity-modulated radiotherapy (IMRT) treatment planning with three-dimensional conformal radiotherapy (3D-CRT) planning for paranasal sinus carcinoma.

Materials And Methods: Treatment plans using traditional 3-field technique, 3D-CRT planning, and inverse planning IMRT were developed for a case of paranasal sinus cancer requiring adjuvant radiotherapy. Plans were compared with respect to dose conformality, dose-volume histograms, doses to critical normal tissues, and ease of treatment delivery.

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Purpose: To update our experience with intensity-modulated radiotherapy (IMRT) in the treatment of nasopharyngeal carcinoma (NPC).

Methods And Materials: Between April 1995 and October 2000, 67 patients underwent IMRT for NPC at the University of California-San Francisco (UCSF). There were 20 females and 47 males, with a mean age of 49 (range 17-82).

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