BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) will show abnormal fractional anisotropy (FA) in the normal-appearing brain after prophylactic cranial irradiation (PCI). These abnormalities will be more accentuated in patients with underlying vascular risk factors.
Radiation therapy is an effective treatment after incomplete resection of desmoid tumors. We did not observe a benefit for tumor doses exceeding 50 Gy. In some patients with circumscribed intraabdominal desmoid tumors, radiation therapy might be a treatment option with low toxicity, if 3-D treatment planning is utilized.
Prior to an image-guided surgical intervention, a correlation between the patient's data set and the surgical site is required. This study introduces a markerless registration method for cranio-maxillofacial surgery that is based on a high-resolution laser scan of the patient's skin surface. The Surgical Segment Navigator SSN++ rejects contaminated surface measurements in a way similar to the bluescreen technique. Acquisition of the spatial position and the corresponding surface color of each laser-scanned point facilitates this bluescreen method, removing points with a defined surface color, e.g., blue or green points. The accuracy of the laser-scan-based registration was measured via additional intraoral titanium-markers. These markers served only to check the accuracy of the markerless registration process. In twelve patients, the stability and accuracy of the data set alignment was evaluated for high-(300,000 surface points), medium-, and low-resolution (down to 3,750 surface points) laser scanning. The accuracy of the registration technique was best for high-resolution laser scanning (mean deviation 1.1 mm; maximum deviation 1.8 mm). Low-resolution laser scans revealed inaccuracies up to 6 mm.
The techniques of virtual reality keep gaining in importance for medical applications. Many applications are still being developed or are still in the form of a prototype. However, it is already clear that developments in this area will have a considerable effect on the surgeon's routine work.
The radiologic imaging methods play an important role in the precise staging as basic requirement for an effective concept of tumor therapy. The accuracy of ultrasound in the primary staging according to the TNM-classification (UICC) was therefore prospectively investigated in 260 patients with head and neck tumors of the clinical stages T1N0 to T4N3. The clinically (C1) and sonographically (C2) evaluated pretherapeutic stages were compared to the postoperative histopathologic tumor classifications. The clinical staging was correct in 75.0%, high in 7.7%, low in 17.3%, the N-stages were correct in 59.2%, high in 17.7%, low in 23.1%. The sonographic staging was apparently superior with the T-classifications correct in 92.3%, high in 7.7%, low 0.0%. The N-stages were correct in 89.6%, high in 9.2%, low in 1.2%. The accuracy of combined TN classification rose from clinical 46.5% to 84.6% by sonography. Accompanying inflammations, foregoing biopsies and tooth extractions were the main reasons for incorrect staging. Therefore, the thorough sonographic investigation performed after the clinical examination and before invasive procedures, due to little patient discomfort, good availability and high accuracy, is an excellent sectional imaging method for staging, therapy-planning and follow up of tumors of the head and neck especially of the orofacial regions.
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