Automatic Segmentation of Brain Structures for Radiation Therapy Planning

Delineation of structures to irradiate (the tumors) as well as structures to be spared (e.g., optic nerve, brainstem, or eyes) is required for advanced radiotherapy techniques. Due to a lack of time and the number of patients to be treated these cannot always be segmented accurately which may lead to suboptimal plans. A possible solution is to develop methods to identify these structures automatically. This study tests the hypothesis that a fully automatic, atlas-based segmentation method can be used to segment most brain structures needed for radiotherapy plans even tough tumors may deform normal anatomy substantially. This is accomplished by registering an atlas with a subject volume using a combination of rigid and non-rigid registration algorithms. Segmented structures in the atlas volume are then mapped to the corresponding structures in the subject volume using the computed transformations. The method we propose has been tested on two sets of data, i.e., adults and children/young adults. For the first set of data, contours obtained automatically have been compared to contours delineated manually by three physicians. For the other set qualitative results are presented

Prognostic Value of FDG-PET in Patients with Oropharyngeal Carcinoma Treated with Concurrent Chemoradiotherapy

Purpose: The purpose of this study was to evaluate the predictive value of 2-deoxy-2-[F-18] fluoro-D-glucose-positron emission tomography (FDG-PET) following concurrent chemoradiotherapy (CRT) on survival in patients with carcinoma of the oropharynx (OPC). Methods: Eighteen patients with primary OPC who underwent PET pre- and post-CRT were evaluated prospectively for survival. The prognostic performance of post-CRT PET and CT for recurrence was compared. Results: Patients with positive post-CRT PET exhibited significantly lower 2-year cause-specific survival and disease-free survival (50 % vs. 91%, PG0.05 and 0 % vs. 83%, PG0.0001); however, patients with positive post-CRT CT did not exhibit any significant difference (67 % vs. 83%, P= 0.416 and 50 % vs. 75%, P=0.070). Other factors, such as clinical and pre-CRT PET variables, also did not indicate any significant difference. The accuracy of prediction of residual and local recurrence for post-CRT PET and CT (local%/regional%) was 83%/94 % and 83%/78%, respectively. Conclusion: OPC patients with positive post-CRT PET exhibit poor survival. The prognostic accuracy of post-CRT PET is superior to that of CT. The results of post-CRT FDG-PET should be included in the management of the OPC patients

Single Agent Irinotecan for the Treatment of Metastatic or Recurrent Squamous Carcinoma of the Head and Neck (SCCHN)

Background Patients with recurrent or metastatic head and neck cancer (HNC) have a poor response and survival with currently available chemotherapy agents. Thus new agents are needed. We report the results of a phase II trial of irinotecan in patients with metastatic or recurrent HNC. Patients and Methods Chemonaive patients were treated with irinotecan 125 mg/m 2 on a weekly schedule for four weeks, followed by a two week rest. However, due to excessive toxicity, the dose and schedule of irinotecan was changed to 75 mg/m 2 on days 1 and 8 of a 21 day cycle. All previously treated patients received 75 mg/m 2 on days 1 and 8 of a 21 day cycle. Results Forty-nine patients were enrolled on study. The response rate was 20% in the chemonaive patients treated at the 125 mg/m 2 dose. The response rate decreased to 12.5% at the 75 mg/m 2 dose. In the previously treated cohort, the response rate was 20%. Median survival for the chemonaive and previously treated cohorts were 6.7 months and 5.0 months, respectively. Conclusions Irinotecan has modest activity in chemonaive and previously treated HNC, thus it merits further study in this advanced disease population