A fresh look at the (non-)Abelian Landau-Khalatnikov-Fradkin transformations

The Landau-Khalatnikov-Fradkin transformations (LKFTs) allow to interpolate $n$-point functions between different gauges. We first offer an alternative derivation of these LKFTs for the gauge and fermions field in the Abelian (QED) case when working in the class of linear covariant gauges. Our derivation is based on the introduction of a gauge invariant transversal gauge field, which allows a natural generalization to the non-Abelian (QCD) case of the LKFTs. To our knowledge, within this rigorous formalism, this is the first construction of the LKFTs beyond QED. The renormalizability of our setup is guaranteed to all orders. We also offer a direct path integral derivation in the non-Abelian case, finding full consistency.Comment: 16 page

Adjuvant radiotherapy after radical cystectomy for patients with muscle invasive bladder cancer : a phase II trial

Background: Neo-adjuvant chemotherapy followed by radical cystectomy with extended pelvic lymph node dissection is considered to be the treatment of choice for patients with muscle invasive bladder cancer (MIBC). Despite this aggressive treatment the outcome is poor and ultimately, 30% of the patients with >= pT3 tumors develop a pelvic recurrence. We hypothesize that postoperative adjuvant external beam radiotherapy (EBRT) might prevent local and lymph node recurrence and improve disease free-and overall survival as loco-regional recurrence is linked to the development of distant metastasis. Methods: We plan to perform a multicentric prospective phase two study including 76 patients. Eligible patients are patients with MIBC, treated with radical cystectomy and presenting with >= 1 of the following characteristics: - Pathological (p) T3 stage + presence of lymphovascular invasion on pathological examination - pT4 stage - < 10 lymph nodes removed - positive lymph nodes - positive surgical margins Patients will have a F-18-FDG PET-CT to rule out the presence of distant metastasis prior to EBRT. A median dose of 50 Gy in 25 fractions is prescribed to the pelvic lymph node regions with inclusion of the operative bladder bed in case of a positive surgical margin. Patients with suspected lymph nodes on PET-CT can still be included in the trial, but a simultaneous integrated boost to 74Gy to the positive lymph nodes will be delivered. Blood and urine samples will be collected on day-1 and last day of EBRT for evaluation of biomarkers. The primary endpoint is evaluation of acute >= Grade 3 intestinal or grade 4 urinary toxicity, in case of a neo-bladder reconstruction, within 12 weeks after EBRT. Secondary endpoints are: assessment of QOL, late RTOG toxicity, local control, disease free survival and overall survival. Biomarkers in urine and blood will be correlated with secondary survival endpoints. Discussion: This is a prospective phase 2 trial re-assessing the feasibility of adjuvant radiotherapy in high-risk MIBC

Effect of radiation dose on the prevalence of apical periodontitis : a dosimetric analysis

Objectives : The objective of this study is to analyse the effect of the radiation dose of oral radiotherapy for cancer on the presence of apical periodontitis in patients without dental pre-screening or specific preventive measures. Materials and methods : All selected patients had been diagnosed with cancer in the head and neck region and presented in the dental clinic post radiotherapy with side effects (mainly radiation caries). The panoramic radiographs of these patients were examined for several parameters, including tooth decay and apical periodontitis. The total radiation dose per tooth was determined. Results : A total of 36 patient files were included, which accounted for 628 teeth to be scored. Tooth decay was present in 88.2% of teeth. Radiographic signs of apical periodontitis were found in 9.1% of the teeth. Teeth with apical periodontitis had significantly more caries present. The radiation dose was significantly higher for teeth with apical periodontitis (37.2 vs. 24.9 Gy). Binary logistic regression found the radiation dose to be the only explanatory variable in the presence of apical periodontitis. Conclusions : This study found that in zones with higher radiation dose, inflammation of the jawbone due to bacterial infection of the root canal is more likely to develop. This is probably due to bone changes post radiotherapy. Clinical relevance : An increase of this prevalance of apical periodontitis in irradiated bone found in this study needs to be taken into account in the dental evaluation before the start of radiotherapy

Early biomarkers related to secondary primary cancer risk in radiotherapy treated prostate cancer patients: IMRT versus IMAT

AbstractPurposeTo investigate whether rotational techniques (Volumetric Modulated Arc Therapy – VMAT) are associated with a higher risk for secondary primary malignancies compared to step-and-shoot Intensity Modulated Radiation Therapy (ss-IMRT). To this end, radiation therapy (RT) induced DNA double-strand-breaks and the resulting chromosomal damage were assessed in peripheral blood T-lymphocytes of prostate cancer (PCa) patients applying γH2AX foci and G0 micronucleus (MN) assays.Methods and materialsThe study comprised 33PCa patients. A blood sample was taken before start of therapy and after the 1st and 3rd RT fraction to determine respectively the RT-induced γH2AX foci and MN. The equivalent total body dose (DETB) was calculated based on treatment planning data.ResultsA linear dose response was obtained for γH2AX foci yields versus DETB while MN showed a linear-quadratic dose response. Patients treated with large volume (LV) VMAT show a significantly higher level of induced γH2AX foci and MN compared to IMRT and small volume (SV) VMAT (p<0.01). Assuming a linear-quadratic relationship, a satisfactory correlation was found between both endpoints (R2 0.86).ConclusionsBiomarker responses were governed by dose and irradiated volume of normal tissues. No significant differences between IMRT and rotational therapy inherent to the technique itself were observed

Clinical Results after High-Dose Intensity-Modulated Radiotherapy for High-Risk Prostate Cancer

Purpose. Patients with high-risk prostate cancer (PC) can be treated with high-dose intensity-modulated radiotherapy (IMRT) and long-term androgen deprivation (AD). In this paper we report on (i) late toxicity and (ii) biochemical (bRFS) and clinical relapse-free survival (cRFS) of this combined treatment. Methods. 126 patients with high-risk PC (T3-4 or PSA >20 ng/mL or Gleason 8–10) and ≥24 months of followup were treated with high-dose IMRT and AD. Late toxicity was recorded. Biochemical relapse was defined as PSA nadir +2 ng/mL. Clinical relapse was defined as local failure or metastases. Results. The incidence of late grade 3 gastrointestinal and genitourinary toxicity was 2 and 6%, respectively. Five-year bRFS and cRFS were 73% and 86% respectively. AD was a significant predictor of bRFS (P = 0.001) and cRFS (P = 0.01). Conclusion. High-dose IMRT and AD for high-risk PC offers excellent biochemical and clinical control with low toxicity

Landau-Khalatnikov-Fradkin transformations, Nielsen identities, their equivalence, and implications for QCD

The Landau-Khalatnikov-Fradkin transformations (LKFTs) represent an important tool for probing the gauge dependence of the correlation functions within the class of linear covariant gauges. Recently these transformations have been derived from first principles in the context of non-Abelian gauge theory (QCD) introducing a gauge invariant transverse gauge field expressible as an infinite power series in a Stueckelberg field. In this work we explicitly calculate the transformation for the gluon propagator, reproducing its dependence on the gauge parameter at the one-loop level and elucidating the role of the extra fields involved in this theoretical framework. Later on, employing a unifying scheme based upon the Becchi-Rouet-Stora-Tyutin symmetry and a resulting generalized Slavnov-Taylor identity, we establish the equivalence between the LKFTs and the Nielsen identities which are also known to connect results in different gauges

Clinical and imaging tools in the early diagnosis of prostate cancer, a review

Measurement of serum Prostate Specific Antigen (PSA) level is useful to detect early prostate cancer. PSA-screening may reduce the mortality rate from prostate cancer, but this is associated with a high rate of overdiagnosis and overtreatment. To improve the detection of clinically significant cancers, several auxiliary clinical and imaging tools can be used. The absolute PSA value can be complemented with parameters such as PSA velocity, PSA density and free/total PSA. Transrectal Ultrasound (TRUS) has only moderate accuracy in the detection of prostate carcinoma, but is very useful in the estimation of prostate volume and thus calculation of PSA-density. The role of Magnetic Resonance Imaging (MRI) in diagnosis and staging of prostate carcinoma is rapidly increasing. Morphologic T2- weighted MR images (T2-WI), preferably with an endorectal coil, depict the prostatic anatomy with high resolution and can detect tumoral areas within the peripheral zone of the prostate. Addition of MR spectroscopic imaging (MRSI), dynamic contrast enhanced MRI (DCE-MRI) and/or diffusion weighted imaging (DWI) further increase the diagnostic performance of MRI. The gold standard for diagnosis of prostate carcinoma is histological assessment obtained by transrectal ultrasound-guided systematic core needle biopsy. In the future, imaging-based targeted biopsies may improve the biopsy yield and decrease the number of biopsy cores. Computed Tomography (CT) and positron emission tomography (PET) have no value in early prostate cancer detection and the indications are limited to lymph node staging and detection of distant metastases