Hypofractionated stereotactic radiotherapy of limited brain metastases: a single-centre individualized treatment approach

<p>Abstract</p> <p>Background</p> <p>We retrospectively report treatment results of our single-centre experience with hypofractionated stereotactic radiotherapy (hfSRT) of limited brain metastases in primary and recurrence disease situations. Our aim was to find the most effective and safe dose concept.</p> <p>Methods</p> <p>From 04/2006 to 12/2010, 75 patients, with 108 intracranial metastases, were treated with hfSRT. 52 newly diagnosed metastases (48%), without up-front whole brain radiotherapy (WBRT), received hfSRT as a primary treatment. 56 metastases (52%) received a prior WBRT and were treated in this study in a recurrence situation. Main fractionation concepts used for primary hfSRT were 6-7x5 Gy (61.5%) and 5x6 Gy (19.2%), for recurrent hfSRT 7-10x4 Gy (33.9%) and 5-6x5 Gy (33.9%).</p> <p>Results</p> <p>Median overall survival (OS) of all patients summed up to 9.1 months, actuarial 6-and 12-month-OS was 59% and 35%, respectively. Median local brain control (LC) was 11.9 months, median distant brain control (DC) 3.9 months and intracranial control (IC) 3.4 months, respectively. Variables with significant influence on OS were Gross Tumour Volume (GTV) (p = 0.019), the biological eqivalent dose (calculated on a 2 Gy single dose, EQD2, α/β = 10) < and ≥ median of 39 Gy (p = 0.012), extracerebral activity of the primary tumour (p < 0.001) and the steroid uptake during hfSRT (p = 0.03). LC was significantly influenced by the EQD2, ≤ and > 35 Gy (p = 0.004) in both uni- and multivariate Cox regression analysis. Median LC was 14.9 months for EQD2 >35 Gy and 3.4 months for doses ≤35 Gy, respectively. Early treatment related side effects were usually mild. Nevertheless, patients with a EQD2 >35 Gy had higher rates of toxicity (31%) than ≤35 Gy (8.3%, p=0.026).</p> <p>Conclusion</p> <p>Comparing different dose concepts in hfSRT, a cumulative EQD2 of ≥35 Gy seems to be the most effective concept in patients with primary or recurrent limited brain metastases. Despite higher rates of only mild toxicity, this concept represents a safe treatment option.</p

Measurement of B(b)over-bar Correlations At the Cern P(p)over-bar Collider

We report on measurements of correlated bbBAR production in ppBAR collisions at square-root s = 630 GeV, using dimuon data to tag both the b and bBAR quarks. Starting from an inclusive dimuon sample we obtain improved cross-sections for single inclusive beauty production and confirm our earlier results on B0-B0BAR mixing. From a study of bbBAR correlations we derive explicit cross-sections for semi-differential bbBAR production. We compare the measured cross-sections and correlations to O(alpha(s)3) QCD predictions and find good quantitative agreement. From the measured angular distributions we establish a sizeable contribution from higher order QCD processes with a significance of about seven standard deviations. A large nonperturbative contribution to these higher order corrections is excluded

Measurement of alpha-s from b anti-b production at the CERN p anti-p collider

The UA1 Collaboration has recently improved its measurement of the beauty production cross-section by including explicit measurements of correlations. Using these data we have determined the strong coupling constant alpha(s). The comparison of the measured cross-section for 2-body final states with O(alpha(s)(3)) QCD predictions yields a measurement of alpha(S)(20 GeV) = 0.145(-0.010exp-0.016 th)(+0.012+0.013), corresponding to alpha(S)(M(Z)) = 0.113(-0.006 exp-0.009 th)(+0.007+0.008). This is the first theoretically well-defined measurement of alpha(S) from a purely hadronic production process. Evaluating alpha(S) from cross-sections at different Q(2)-values we find that the running of alpha(S) is needed for internal consistency of the UA1 data

Measurement of B0 - anti-B0 mixing at the CERN S p anti-p S collider

We report on a new measurement of B0-BBAR0 mixing at the CERN SppBARS Collider. Mixing is measured in the non-isolated high mass dimuon sample using data from the 1988-1989 collider runs. The measured value of the mixing parameter, chi, is 0.145 +/- 0.035(stat.) +/- 0.014(syst.). The average of this measurement and that from our 1984-1985 data is chi = 0.148 +/- 0.029(stat.) +/- 0.017(syst.) assuming fully correlated systematic errors. Using the measurement of chi-d from ARGUS and CLEO, we obtain chi-s = 0.50 +/- 0.20, which gives a limit of chi-s > 0.17 (0.12) at 90% (95%) CL. Including the measurements of chi from the ALEPH and L3 experiments gives chi-s = 0.53 +/- 0.15, and a limit of chi-s > 0.27 (0.23) at 90% (95%) CL