The aim of this report is dosimetric evaluation for an intraoperative fusion computed tomography (CT) as a superior predictor of 1-month CT based dosimetry in comparison to transrectal ultrasound (TRUS) in permanent interstitial prostate brachytherapy.
Data of 65 patients treated with seed implantation were analyzed. All procedures has been performed with patients in the lithotomy position inside the O-arm system. An end-fine probe is used as a landmark to fuse TRUS and O-arm-based CT images. There was no difference in the patient's position, probe position, and timing of image acquisition between the two imaging modalities. Dose-volume histogram (DVH) parameters such as the dose to 90% of prostate volume (D90) has been analyzed.
The area under the curve of the receiver operating characteristic tended to be larger on fusion CT than on TRUS for most DVH parameters (71.85% vs. 59.59% for D90; p = 0.07). Significant relationships between fusion CT and 1-month CT were confirmed using Pearson's correlation coefficients for most DVH parameters (R = 0.48, p < 0.01 for D90), although the relationship between TRUS and 1-month CT was poor. Large dose reduction (35 Gy for D90) was seen from TRUS to fusion CT, especially in patients with high body weight and small prostate volume.
Intraoperative fusion CT appears to have higher predictive power for 1-month CT-based dosimetry than TRUS. A prospective trial using fusion CT-based planning is warranted.
Journal of contemporary brachytherapy. 2016 Feb 09 [Epub]
Hiromichi Ishiyama, Akane Sekiguchi, Takefumi Satoh, Hideyasu Tsumura, Kouji Takenaka, Shogo Kawakami, Ken-Ichi Tabata, Kentaro Kobayashi, Masatsugu Iwamura, Kazushige Hayakawa
Department of Radiology and Radiation Oncology., Department of Radiology and Radiation Oncology., Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan., Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan., Department of Radiology and Radiation Oncology., Department of Radiology and Radiation Oncology., Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan., Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan., Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan., Department of Radiology and Radiation Oncology.