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Object Cone beam CT (CBCT) image guidance has recently been adopted for the delivery of spine radiosurgery. In 2007, the authors' institution began a dedicated spine radiosurgery program using the Elekta Synergy S system, which incorporates CBCT technology. In this study, the authors prospectively evaluated the Synergy S platform as a dedicated spine radiosurgery delivery system, including an evaluation of the accuracy of patient positioning using this technology, as part of a quality assurance program. Methods One hundred sixty-six spine and paraspinal lesions were treated using the Elekta Synergy S 6-MV LINAC with a beam modulator and CBCT image guidance combined with a HexaPOD couch that allows correction of patient positioning in 3 translational and 3 rotational directions. Stratifying the lesion by location, there were 28 cervical, 69 thoracic, 48 lumbar, and 21 sacral lesions. The most common histological types for the metastatic lesions (136 cases total) were breast, lung, sarcomas, and renal cells. The most common benign tumors (30 cases total) included 10 schwannomas, 5 neurofibromas, and 5 meningiomas. Twenty-eight lesions (17%) were intradural. To measure intratreatment patient movement, 3 quality assurance CBCTs were performed and recorded at separate times: immediately before treatment started; at the first third of the procedure; and at the second third of the procedure. The positioning data and fused images of the planning CT and CBCT were analyzed to determine intrafraction patient movements. From each of 3 quality assurance CBCT images, 3 translational and 3 rotational coordinates were obtained. Results The prescribed dose to the gross tumor volume, delivered in a single fraction, ranged from 12 to 20 Gy (mean 16 Gy) in this cohort. This dose was delivered by between 7 and 14 coplanar intensity-modulated radiation therapy beams (mean 9 beams). The gross tumor volumes ranged from 1.2 to 491.7 cm3 (mean 39.2 cm3). Mean treatment time including setup was 64 minutes. At the first third of the treatment, the magnitude of the 3D translational vector (X, Y, Z) was 1.1 ± 0.7 mm. Similarly, the 3D translational vector at the second third of the treatment was 1.0 ± 0.6 mm. The means ± SDs of the rotational angles were 0.2° ± 0.4°, 0.4° ± 0.5°, and 0.3° ± 0.5° along yaw, roll, and pitch, respectively, at the first third of the treatment, and 0.2° ± 0.3°, 0.4° ± 0.5°, and 0.4° ± 0.5°, respectively, at the second third of the treatment. Conclusions Single-fraction spine radiosurgery performed using the Synergy S platform and incorporating CBCT image guidance was determined to be feasible, accurate, and safe. This technique provides an overall translational position accuracy of < 2.0 mm.

Cultivated maize ( Zea mays ) and several other members of the Tribe Andropogoneae produce unisexual florets. In maize, the formation of two staminate florets in each spikelet on the tassel and a single pistillate floret in each spikelet on the ear includes a pistil abortion process that requires the action of the TASSELSEED2 gene. In Eastern gamagrass ( Tripsacum dactyloides ) the GYNOMONOECIOUS SEX FORM1 gene appears to perform a similar role in pistil abortion. These genes were shown to be homeologs by restriction fragment length polymorphism mapping and by the failure of the gsf1 and ts2 alleles to complement one another in intergeneric hybrids. Molecular analysis of the gsf1 allele shows that it is caused by a 1.4-kb deletion mutation. Both TASSELSEED2 and GYNOMONOECIOUS SEX FORM1 show similar expression patterns in subepidermal cells of pistils just before abortion. These results suggest that the formation of staminate florets in the Andropogoneae represents a monophyletic trait.

Cone beam CT (CBCT) image guidance has recently been adopted for the delivery of spine radiosurgery. In 2007, the authors' institution began a dedicated spine radiosurgery program using the Elekta Synergy S system, which incorporates CBCT technology. In this study, the authors prospectively evaluated the Synergy S platform as a dedicated spine radiosurgery delivery system, including an evaluation of the accuracy of patient positioning using this technology, as part of a quality assurance program.One hundred sixty-six spine and paraspinal lesions were treated using the Elekta Synergy S 6-MV LINAC with a beam modulator and CBCT image guidance combined with a HexaPOD couch that allows correction of patient positioning in 3 translational and 3 rotational directions. Stratifying the lesion by location, there were 28 cervical, 69 thoracic, 48 lumbar, and 21 sacral lesions. The most common histological types for the metastatic lesions (136 cases total) were breast, lung, sarcomas, and renal cells. The most common benign tumors (30 cases total) included 10 schwannomas, 5 neurofibromas, and 5 meningiomas. Twenty-eight lesions (17%) were intradural. To measure intratreatment patient movement, 3 quality assurance CBCTs were performed and recorded at separate times: immediately before treatment started; at the first third of the procedure; and at the second third of the procedure. The positioning data and fused images of the planning CT and CBCT were analyzed to determine intrafraction patient movements. From each of 3 quality assurance CBCT images, 3 translational and 3 rotational coordinates were obtained.The prescribed dose to the gross tumor volume, delivered in a single fraction, ranged from 12 to 20 Gy (mean 16 Gy) in this cohort. This dose was delivered by between 7 and 14 coplanar intensity-modulated radiation therapy beams (mean 9 beams). The gross tumor volumes ranged from 1.2 to 491.7 cm(3) (mean 39.2 cm(3)). Mean treatment time including setup was 64 minutes. At the first third of the treatment, the magnitude of the 3D translational vector (X, Y, Z) was 1.1 ± 0.7 mm. Similarly, the 3D translational vector at the second third of the treatment was 1.0 ± 0.6 mm. The means ± SDs of the rotational angles were 0.2° ± 0.4°, 0.4° ± 0.5°, and 0.3° ± 0.5° along yaw, roll, and pitch, respectively, at the first third of the treatment, and 0.2° ± 0.3°, 0.4° ± 0.5°, and 0.4° ± 0.5°, respectively, at the second third of the treatment.Single-fraction spine radiosurgery performed using the Synergy S platform and incorporating CBCT image guidance was determined to be feasible, accurate, and safe. This technique provides an overall translational position accuracy of2.0 mm.

Growth of two droplet families and a polymer seed family as a function of percent monomer conversion in PVC miniemulsion synthesis demonstrates that polymerization in droplets predominates to ∼ 30–40% conversion, whereupon polymerization of seed becomes favored. This difference appears to be due to a liquid-to-solid phase change in the forming particles during the course of polymerization.

A soap/alcohol miniemulsion in combination with an homogenized mixture of monomer and initiator is utilized to generate PVC plastisol. Droplet distributions generated consist of two distinct types. Judicious control of soap-to-alcohol ratio allows control of the number and size of the smaller droplet family; homogenization and initiator water solubility affect the other. Final latex particle distribution may be unimodal or bimodal depending upon manipulation of these factors.