Experimental assessment of inter-centre variation in stopping-power and range prediction in particle therapy

Purpose: Experimental assessment of inter-centre variation and absolute accuracy of stopping-power ratio (SPR) prediction within 17 particle therapy centres of the European Particle Therapy Network. Material and methods: A head and body phantom with seventeen tissue-equivalent materials were scanned consecutively at the participating centres using their individual clinical CT scan protocol and translated into SPR with their in-house CT-number-to-SPR conversion. Inter-centre variation and absolute accuracy in SPR prediction were quantified for three tissue groups: lung, soft tissues and bones. The integral effect on range prediction for typical clinical beams traversing different tissues was determined for representative beam paths for the treatment of primary brain tumours as well as lung and prostate cancer. Results: An inter-centre variation in SPR prediction (2 sigma) of 8.7%, 6.3% and 1.5% relative to water was determined for bone, lung and soft-tissue surrogates in the head setup, respectively. Slightly smaller variations were observed in the body phantom (6.2%, 3.1%, 1.3%). This translated into inter-centre variation of integral range prediction (2 sigma) of 2.9%, 2.6% and 1.3% for typical beam paths of prostate-, lung-and primary brain-tumour treatments, respectively. The absolute error in range exceeded 2% in every fourth participating centre. The consideration of beam hardening and the execution of an independent HLUT validation had a positive effect, on average. Conclusion: The large inter-centre variations in SPR and range prediction justify the currently clinically used margins accounting for range uncertainty, which are of the same magnitude as the inter-centre variation. This study underlines the necessity of higher standardisation in CT-number-to-SPR conversion. (C) 2021 The Authors. Published by Elsevier B.V

Carbon ion therapy for ameloblastic carcinoma

Ameloblastic carcinomas are rare odontogenic tumors. Treatment usually consists of surgical resection and sometimes adjuvant radiation. We report the case of a 71 year-old male patient undergoing carbon ion therapy for extensive local relapse of ameloblastic carcinoma. Treatment outcome was favourable with a complete remission at 6 weeks post completion of radiotherapy while RT-treatment itself was tolerated well with only mild side effects. High dose radiation hence is a potential alternative for patients unfit or unwilling to undergo extensive surgery or in cases when only a subtotal resection is planned or the resection is mutilating

Raster-scanned carbon ion therapy for malignant salivary gland tumors: acute toxicity and initial treatment response

<p>Abstract</p> <p>Background and purpose</p> <p>To investigate toxicity and efficacy in high-risk malignant salivary gland tumors (MSGT) of the head and neck. Local control in R2-resected adenoid cystic carcinoma was already improved with a combination of IMRT and carbon ion boost at only mild side-effects, hence this treatment was also offered to patients with MSGT and microscopic residual disease (R1) or perineural spread (Pn+).</p> <p>Methods</p> <p>From November 2009, all patients with MSGT treated with carbon ion therapy were evaluated. Acute side effects were scored according to CTCAE v.4.03. Tumor response was assessed according to RECIST where applicable.</p> <p>Results</p> <p>103 patients were treated from 11/2009 to 03/2011, median follow-up is 6 months. 60 pts received treatment following R2 resections or as definitive radiation, 43 patients received adjuvant radiation for R1 and/or Pn+. 16 patients received carbon ion treatment for re-irradiation. Median total dose was 73.2 GyE (23.9 GyE carbon ions + 49,9 Gy IMRT) for primary treatment and 44.9 GyE carbon ions for re-irradiation. All treatments were completed as planned and generally well tolerated with no > CTC°III toxicity. Rates of CTC°III toxicity (mucositis and dysphagia) were 8.7% with side-effects almost completely resolved at first follow-up.</p> <p>47 patients showed good treatment responses (CR/PR) according to RECIST.</p> <p>Conclusion</p> <p>Acute toxicity remains low in IMRT with carbon ion boost also in R1-resected patients and patients undergoing re-irradiation. R2-resected patients showed high rates of treatment response, though follow-up is too short to assess long-term disease control.</p

Measurement of the Neutral Current Cross Section and Search for Contact Interactions with the H1 Experiment at HERA

A measurement of the inclusive neutral current cross section for deep inelastic positron-proton scattering and a subsequent search for electron-quark contact interactions are presented. The analysis is based on data taken in 1999 and 2000 at a centre-of-mass energy of sqrt(s)=319 GeV with the H1 experiment at HERA. Substantial systematic improvements are achieved for the reconstruction of neutral current events at large four-momentum transfer Q^2. The precise measurement of the scattered electron using solely calorimetric information is established. The single and double differential cross sections dsigma/dQ^2 and d^2sigma/dxdQ^2 are measured in the range of 200<=Q^2<=30000 GeV^2 and 0.0032<=x_Bjorken<=0.65. The results are in good agreement with the Standard Model QCD prediction. The compatibility of the cross section measurement with the Standard Model and extensions beyond is quantified using a novel chi^2 fit, which strongly reduces the dependence on the shape of the proton parton densities. No significant indications of new physics are found. The analysis yields an upper bound on the quark radius of r_quark<1.1*10^(-18) m (CL=95%) and lower limits on electron-quark compositeness scales ranging from 1.5 to 4.8 TeV. The results are comparable to those of other analyses performed at HERA, LEP or TeVatron

Carbon ion therapy for advanced sinonasal malignancies: feasibility and acute toxicity

Abstract Purpose To evaluate feasibility and toxicity of carbon ion therapy for treatment of sinonasal malignancies. First site of treatment failure in malignant tumours of the paranasal sinuses and nasal cavity is mostly in-field, local control hence calls for dose escalation which has so far been hampered by accompanying acute and late toxicity. Raster-scanned carbon ion therapy offers the advantage of sharp dose gradients promising increased dose application without increase of side-effects. Methods Twenty-nine patients with various sinonasal malignancies were treated from 11/2009 to 08/2010. Accompanying toxicity was evaluated according to CTCAE v.4.0. Tumor response was assessed according to RECIST. Results Seventeen patients received treatment as definitive RT, 9 for local relapse, 2 for re-irradiation. All patients had T4 tumours (median CTV1 129.5 cc, CTV2 395.8 cc), mostly originating from the maxillary sinus. Median dose was 73 GyE mostly in mixed beam technique as IMRT plus carbon ion boost. Median follow- up was 5.1 months [range: 2.4 - 10.1 months]. There were 7 cases with grade 3 toxicity (mucositis, dysphagia) but no other higher grade acute reactions; 6 patients developed grade 2 conjunctivits, no case of early visual impairment. Apart from alterations of taste, all symptoms had resolved at 8 weeks post RT. Overall radiological response rate was 50% (CR and PR). Conclusion Carbon ion therapy is feasible; despite high doses, acute reactions were not increased and generally resolved within 8 weeks post radiotherapy. Treatment response is encouraging though follow-up is too short to estimate control rates or evaluate potential late effects. Controlled trials are warranted.</p