A virtual frame system for stereotactic radiosurgery planning.

PURPOSE: We describe a computerized (or virtual) model of a stereotactic head frame to enable planning prior to the day of radiosurgery. The location of the virtual frame acts as a guide to frame placement on the day of the procedure. METHODS AND MATERIALS: The software consists of a triangular mesh representation of the essential frame hardware that can be overlaid with any MR scan of the patient and manipulated in three dimensions. The software calculates regions of the head that will actually be accessible for treatment, subject to the geometric constraints of the Leksell Gamma Knife hardware. DICOM-compliant MR images with virtual fiducial markers overlaid onto the image can then be generated for recognition by the treatment planning system. RESULTS: Retrospective evaluation of the software on 24 previously treated patients shows a mean deviation of the position of the virtual frame from the actual frame position of 1.6 +/- 1.3 mm. Initial clinical use on five patients indicates an average discrepancy of the virtual frame location and the actual frame location of <1 mm. MR images with virtual fiducial markers can be imported into radiosurgical treatment planning software and used to generate an initial treatment plan. CONCLUSIONS: The virtual frame provides a tool for prospective determination of lesion accessibility, optimization of the frame placement, and treatment planning before the day of the procedure. This promises to shorten overall treatment times, improve patient comfort, and reduce the need for repeat treatments due to suboptimally placed frames.

Phase II multicenter study of induction chemotherapy followed by concurrent efaproxiral (RSR13) and thoracic radiotherapy for patients with locally advanced non-small-cell lung cancer.

PURPOSE: Efaproxiral (RSR13) reduces hemoglobin oxygen-binding affinity, facilitates oxygen release, and increases tissue pO2. We conducted a phase II multicenter study that assessed the efficacy and safety of efaproxiral when administered with thoracic radiation therapy (TRT), following induction chemotherapy, for treatment of locally advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Fifty-one patients with locally advanced NSCLC were enrolled at 13 sites. Treatment comprised two cycles of paclitaxel (225 mg/m2) and carboplatin (area under the curve, 6), 3 weeks apart, followed by TRT (64 Gy/32 fractions) with concurrent efaproxiral (50 to 100 mg/kg). Survival results were compared with results of study Radiation Therapy Oncology Group (RTOG) 94-10. RESULTS: Overall response rate was 75% (37 of 49 patients). Complete and partial response rates were 6% (three of 49 patients) and 69% (34 of 49 patients), respectively. Median survival time (MST) was 20.6 months (95% CI, 14.0 to 24.2); overall survival rates at 1- and 2-years were 67% and 37%, respectively. Survival results were compared with the sequential (S-CRT) and concurrent (C-CRT) chemoradiotherapy arms of RTOG 94-10. MSTs for cases matched by stage, Karnofsky performance status, and age were: RT-010, 20.6 months; S-CRT, 15.1 months; and C-CRT, 17.9 months. Grade 3 to 4 toxicities related to efaproxiral that occurred in more than one patient included transient hypoxemia (19%), radiation pneumonitis (11%), and fatigue (4%). CONCLUSION: Addition of efaproxiral to S-CRT represents a promising approach in NSCLC treatment, and a randomized study should be pursued. The low incidence of grade 3 to 4 toxicities suggests that the use of efaproxiral instead of a cytotoxic agent, as a radiation sensitizer, may be advantageous.