These data demonstrate that Mg intake of 50% NR in the rat causes a reduced bone mineral content and reduced volume of the distal femur. These changes may be related to altered PTH and 1,25(OH)(2)-vitamin D formation or action as well as to an increase release of substance P and the inflammatory cytokines TNFalpha and IL-1beta.
Findings show that disc degeneration in the sand rat occurs concomitantly with marked architectural bony changes on the endplate face, including loss of smoothness and development of irregular bony margins. Vascular connections were not present between the endplate and disc; this was verified with microCT studies, in vivo vascular tracers, and traditional immunocytochemistry. The canal system within the imaged endplate was revealed to consist of a complex 3D interconnected network.
Background and purpose
Management for in-field failures after thoracic radiation is poorly defined. We evaluated SBRT as an initial or second course of treatment re-irradiating in a prior high dose region.
Materials and methods
Thirty-three patients were treated with re-irradiation defined by the prior 30 Gy isodose line. Kaplan–Meier estimates were performed for local (LC), regional (RC), distant control (DC), and overall survival (OS). The plans when available were summed to evaluate doses to critical structures. Patient and treatment variables were analyzed on UVA for the impact on control and survival measures.
Results
Median follow-up was 17 months. Treatment for sequential courses was as follows: (course1:course2) EBRT:SBRT (24 patients), SBRT:SBRT (7 patients), and SBRT:EBRT (3 patients). Median re-irradiation dose and fractionation was 50 Gy and 10 fractions (fx), with a median of 18 months (6–61) between treatments. Median OS was 21 months and 2 year LC 67%, yet LC for >1 fraction was 88% (p = 0.006 for single vs. multiple). 10 patients suffered chronic grade 2–3 toxicity (6 chest wall pain, 3 dyspnea, 1 esophagitis) and 1 grade 5 toxicity with aorta-esophageal fistula after 54 Gy in 3 fx for a central tumor with an estimated EQD2 to the aorta of 200 Gy.
Conclusion
Tumor control can be established with re-irradiation using SBRT techniques for in-field thoracic failures at the cost of manageable toxicity.
Gamma Knife Radiosurgery (GKRS) has been reported in the treatment of brainstem metastases while dose volume toxicity thresholds remain mostly undefined. A retrospective review of 52 brainstem metastases in 44 patients treated with GKRS was completed. A median dose of 18 Gy (range 10–22 Gy) was prescribed to the tumor margin (median 50 % isodose). 25 patients had undergone previous whole brain radiation therapy. Toxicity was graded by the LENT-SOMA scale. Mean and median follow-up was 10 and 6 months. Only 3 of the 44 patients are living. Multiple brain metastases were treated in 75 % of patients. Median size of lesions was 0.134 cc, (range 0.013–6.600 cc). Overall survival rate at 1 year was 32 % (95 % CI 51.0–20.1 %) with a median survival time of 6 months (95 % CI 5.0–16.5). Local control rate at 6 months and 1 year was 88 % (95 % CI 70–95 %) and 74 % (95 % CI 52–87 %). Cause of death was neurologic in 17 patients, non-neurologic in 20 patients, and unknown in four. Four patients experienced treatment related toxicities. Univariate analysis of tumor volume revealed that volume greater than 1.0 cc predicted for toxicity. A strategy of using lower marginal doses with GKRS to brain stem metastases appears to lead to a lower local control rate than seen with lesions treated within the standard dose range in other locations. Tumor size greater than 1.0 cc predicted for treatment-related toxicity.
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