Purpose/Objective(s)Knowledge about treatment-related toxicity of extracranial stereotactic radiotherapy to the lung is still limited. We conducted a retrospective review of patients treated with stereotactic radiotherapy at our institution to determine the incidence of radiographic toxicity and its correlation with dosimetric parameters.Materials/MethodsWe analyzed the records of 60 patients who received stereotactic radiotherapy to 75 lung lesions between April 1999 and December 2008. Fractionation schemes ranged from 3 x 7-20 Gy to 6 x 5 Gy. A subset of 22 patients with 29 lesions were identified who had a minimum of 12 months radiographic follow-up with serial CT scans of the chest to allow for development of late radiographic changes. Radiographic abnormalities on post-treatment CT scans were graded by two thoracic radiologists using the LENT-SOMA scale to generate a consensus score. Radiologists had pretreatment scans for comparison to distinguish between tumor changes and new post-treatment lung changes. In addition, the radiologists were blinded to the treatment dose and dosimetric parameters of the radiotherapy plan. The grade of radiographic toxicity was correlated with dosimetric parameters, such as tumor and planning target volume (PTV), as well as lung volume irradiated beyond defined threshold doses.ResultsThe median radiographic follow-up is 24 months (range: 13-78.8 months). Based on the consensus opinion of the radiologists, 21 of 29 lesions were scored as high-grade toxicity (i.e. Grade 3 or 4 per the LENT-SOMA scale), 5 lesions had low-grade toxicity (i.e. Grade 1 or 2), and the remainder had no radiographic toxicity. The median time to high-grade toxicity was 6.5 months (range: 1.5-51.3 months) and 15 months to low-grade toxicity (range: 1-24 months). For the analyzed subset of patients, the median PTV was 43.89 cm3 (range: 8.02-195.18 cm3). The median biologically effective dose (BED) was 90 Gy (range: 43-180, alpha/beta = 10 Gy). Treatment plans resulted in a median lung volume receiving ≥ 5 Gy (lung V5Gy) of 19% (range: 1-50%) and a median lung V20Gy of 7% (range: 0-15%). Using a linear mixed effects model, there was no statistically significant correlation between radiographic toxicity and the magnitude of PTV (p = 0.56), BED (p = 0.18), lung V5Gy (p = 0.11), or lung V20Gy (p = 0.15).ConclusionsRadiographic toxicity is a common finding amongst patients treated with thoracic stereotactic radiosurgery. For the analyzed parameters no predictors of radiographic toxicity were identified. Additional dosimetric parameters will be evaluated and correlation with clinical toxicity will be performed for a larger group of patients. Purpose/Objective(s)Knowledge about treatment-related toxicity of extracranial stereotactic radiotherapy to the lung is still limited. We conducted a retrospective review of patients treated with stereotactic radiotherapy at our institution to determine the incidence of radiographic toxicity and its correlation with dosimetric parameters. Knowledge about treatment-related toxicity of extracranial stereotactic radiotherapy to the lung is still limited. We conducted a retrospective review of patients treated with stereotactic radiotherapy at our institution to determine the incidence of radiographic toxicity and its correlation with dosimetric parameters. Materials/MethodsWe analyzed the records of 60 patients who received stereotactic radiotherapy to 75 lung lesions between April 1999 and December 2008. Fractionation schemes ranged from 3 x 7-20 Gy to 6 x 5 Gy. A subset of 22 patients with 29 lesions were identified who had a minimum of 12 months radiographic follow-up with serial CT scans of the chest to allow for development of late radiographic changes. Radiographic abnormalities on post-treatment CT scans were graded by two thoracic radiologists using the LENT-SOMA scale to generate a consensus score. Radiologists had pretreatment scans for comparison to distinguish between tumor changes and new post-treatment lung changes. In addition, the radiologists were blinded to the treatment dose and dosimetric parameters of the radiotherapy plan. The grade of radiographic toxicity was correlated with dosimetric parameters, such as tumor and planning target volume (PTV), as well as lung volume irradiated beyond defined threshold doses. We analyzed the records of 60 patients who received stereotactic radiotherapy to 75 lung lesions between April 1999 and December 2008. Fractionation schemes ranged from 3 x 7-20 Gy to 6 x 5 Gy. A subset of 22 patients with 29 lesions were identified who had a minimum of 12 months radiographic follow-up with serial CT scans of the chest to allow for development of late radiographic changes. Radiographic abnormalities on post-treatment CT scans were graded by two thoracic radiologists using the LENT-SOMA scale to generate a consensus score. Radiologists had pretreatment scans for comparison to distinguish between tumor changes and new post-treatment lung changes. In addition, the radiologists were blinded to the treatment dose and dosimetric parameters of the radiotherapy plan. The grade of radiographic toxicity was correlated with dosimetric parameters, such as tumor and planning target volume (PTV), as well as lung volume irradiated beyond defined threshold doses. ResultsThe median radiographic follow-up is 24 months (range: 13-78.8 months). Based on the consensus opinion of the radiologists, 21 of 29 lesions were scored as high-grade toxicity (i.e. Grade 3 or 4 per the LENT-SOMA scale), 5 lesions had low-grade toxicity (i.e. Grade 1 or 2), and the remainder had no radiographic toxicity. The median time to high-grade toxicity was 6.5 months (range: 1.5-51.3 months) and 15 months to low-grade toxicity (range: 1-24 months). For the analyzed subset of patients, the median PTV was 43.89 cm3 (range: 8.02-195.18 cm3). The median biologically effective dose (BED) was 90 Gy (range: 43-180, alpha/beta = 10 Gy). Treatment plans resulted in a median lung volume receiving ≥ 5 Gy (lung V5Gy) of 19% (range: 1-50%) and a median lung V20Gy of 7% (range: 0-15%). Using a linear mixed effects model, there was no statistically significant correlation between radiographic toxicity and the magnitude of PTV (p = 0.56), BED (p = 0.18), lung V5Gy (p = 0.11), or lung V20Gy (p = 0.15). The median radiographic follow-up is 24 months (range: 13-78.8 months). Based on the consensus opinion of the radiologists, 21 of 29 lesions were scored as high-grade toxicity (i.e. Grade 3 or 4 per the LENT-SOMA scale), 5 lesions had low-grade toxicity (i.e. Grade 1 or 2), and the remainder had no radiographic toxicity. The median time to high-grade toxicity was 6.5 months (range: 1.5-51.3 months) and 15 months to low-grade toxicity (range: 1-24 months). For the analyzed subset of patients, the median PTV was 43.89 cm3 (range: 8.02-195.18 cm3). The median biologically effective dose (BED) was 90 Gy (range: 43-180, alpha/beta = 10 Gy). Treatment plans resulted in a median lung volume receiving ≥ 5 Gy (lung V5Gy) of 19% (range: 1-50%) and a median lung V20Gy of 7% (range: 0-15%). Using a linear mixed effects model, there was no statistically significant correlation between radiographic toxicity and the magnitude of PTV (p = 0.56), BED (p = 0.18), lung V5Gy (p = 0.11), or lung V20Gy (p = 0.15). ConclusionsRadiographic toxicity is a common finding amongst patients treated with thoracic stereotactic radiosurgery. For the analyzed parameters no predictors of radiographic toxicity were identified. Additional dosimetric parameters will be evaluated and correlation with clinical toxicity will be performed for a larger group of patients. Radiographic toxicity is a common finding amongst patients treated with thoracic stereotactic radiosurgery. For the analyzed parameters no predictors of radiographic toxicity were identified. Additional dosimetric parameters will be evaluated and correlation with clinical toxicity will be performed for a larger group of patients.

We report the observation of a giant magnetothermopower (GMT), giant magnetoresistance (GMR), and on magnetization measurements in Co/Cu[111] superlattices grown by molecular beam epitaxy. The maximum value of the GMT (at room temperature) was 14% for a Cu thickness of 9 Å and the maximum GMR (at 4.2 K) was −26% at 7 Å of Cu. Oscillations in the remnant magnetization and the saturation field as a function of Cu thickness with a period of about 10 Å were observed. However, there were no oscillations in the GMT or the GMR. The maximum values of both the GMT and GMR are associated with saturation fields in excess of 40 kOe and with small remnant magnetizations. These results are consistent with the presence of antiferromagnetic coupling.

We measured the far infrared (FIR) absorption by the Gd3+ ion in both randomly oriented and field oriented GdBa2Cu3O7−σ powders in pulsed magnetic fields. The lower g anisotropy in the oriented samples reveals a superposition of two lines at low temperatures: one line with a g factor of 2.02 due to the Gd3+ ions and another line with a g factor of 2.07 which we attribute to the Cu2+ ions.

We measured the far infrared (FIR) resonance absorption from the paramagnetic Gd3+ ion in GdBa2Cu3O7-δ. The g-factor is found to be 2.00. The lineshape shows a broadening at lower temperatures. This indicates that the linewidth contains contributions other than the dipolar interaction.

Radiosulfur exchange has been studied in liquid mixtures of thionyl fluoride and sulfur dioxide. While no exchange occurs between the two species alone, the addition of antimony pentafluoride leads to exchange, both observations being parallel to those observed with the analogous chlorine compounds. The kinetics of the exchange has been interpreted in terms of equilibria involving 1:1 adducts between catalyst and each solvent species as well as a polymeric antimony pentafluoride species. The rate-determining step consists of bimolecular interaction between either 1:1 adduct and the other solvent species. For the reaction between SO2. SbF5 and SOF2 the rate constant is k = 1·85 × 107 exp(−17,300/RT)1. mole−1 sec−1, ΔS≠ = −27·3 ± 3·9 e.u.