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- Daniel, M., et al.
(författare)
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Impact of androgen deprivation therapy on apparent diffusion coefficient and T2w MRI for histogram and texture analysis with respect to focal radiotherapy of prostate cancer
- 2019
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Ingår i: Strahlentherapie und Onkologie (Print). - : Springer Berlin/Heidelberg. - 0179-7158 .- 1439-099X. ; 195:5, s. 402-411
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Accurate prostate cancer (PCa) detection is essential for planning focal external beam radiotherapy (EBRT). While biparametric MRI (bpMRI) including T2-weighted (T2w) and diffusion-weighted images (DWI) is an accurate tool to localize PCa, its value is less clear in the case of additional androgen deprivation therapy (ADT). The aim of this study was to investigate the value of a textural feature (TF) approach on bpMRI analysis in prostate cancer patients with and without neoadjuvant ADT with respect to future dose-painting applications.Methods: 28 PCa patients (54–80 years) with (n = 14) and without (n = 14) ADT who underwent bpMRI with T2w and DWI were analyzed retrospectively. Lesions, central gland (CG), and peripheral zone (PZ) were delineated by an experienced urogenital radiologist based on localized pre-therapeutic histopathology. Histogram parameters and 20 Haralick TF were calculated. Regional differences (i. e., tumor vs. PZ, tumor vs. CG) were analyzed for all imaging parameters. Receiver-operating characteristic (ROC) analysis was performed to measure diagnostic performance to distinguish PCa from benign prostate tissue and to identify the features with best discriminative power in both patient groups.Results: The obtained sensitivities were equivalent or superior when utilizing the TF in the no-ADT group, while specificity was higher for the histogram parameters. However, in the ADT group, TF outperformed the conventional histogram parameters in both specificity and sensitivity. Rule-in and rule-out criteria for ADT patients could exclusively be defined with the aid of TF.Conclusions: The TF approach has the potential for quantitative image-assisted boost volume delineation in PCa patients even if they are undergoing neoadjuvant ADT.
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- Dobsicek Trefna, Hana, 1979, et al.
(författare)
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Quality assurance guidelines for superficial hyperthermia clinical trials: II. Technical requirements for heating devices
- 2017
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Ingår i: Strahlentherapie und Onkologie. - : Springer Science and Business Media LLC. - 1439-099X .- 0179-7158. ; 193:5, s. 351-366
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Forskningsöversikt (refereegranskat)abstract
- Quality assurance (QA) guidelines are essential to provide uniform execution of clinical trials with uniform quality hyperthermia treatments. This document outlines the requirements for appropriate QA of all current superficial heating equipment including electromagnetic (radiative and capacitive), ultrasound, and infrared heating techniques. Detailed instructions are provided how to characterize and document the performance of these hyperthermia applicators in order to apply reproducible hyperthermia treatments of uniform high quality. Earlier documents used specific absorption rate (SAR) to define and characterize applicator performance. In these QA guidelines, temperature rise is the leading parameter for characterization of applicator performance. The intention of this approach is that characterization can be achieved with affordable equipment and easy-to-implement procedures. These characteristics are essential to establish for each individual applicator the specific maximum size and depth of tumors that can be heated adequately. The guidelines in this document are supplemented with a second set of guidelines focusing on the clinical application. Both sets of guidelines were developed by the European Society for Hyperthermic Oncology (ESHO) Technical Committee with participation of senior Society of Thermal Medicine (STM) members and members of the Atzelsberg Circle.
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- Lütgendorf-Caucig, C, et al.
(författare)
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Multicenter evaluation of different target volume delineation concepts in pediatric Hodgkin's lymphoma : a case study
- 2012
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Ingår i: Strahlentherapie und Onkologie (Print). - : Springer Science and Business Media LLC. - 0179-7158 .- 1439-099X. ; 188:11, s. 1025-1030
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: In pediatric Hodgkin's lymphoma (PHL) improvements in imaging and multiagent chemotherapy have allowed for a reduction in target volume. The involved-node (IN) concept is being tested in several treatment regimens for adult Hodgkin's lymphoma. So far there is no consensus on the definition of the IN. To improve the reproducibility of the IN, we tested a new involved-node-level (INL) concept, using defined anatomical boundaries as basis for target delineation. The aim was to evaluate the feasibility of IN and INL concepts for PHL in terms of interobserver variability. PATIENTS AND METHODS: The INL concept was defined for the neck and mediastinum by the PHL Radiotherapy Group based on accepted concepts for solid tumors. Seven radiation oncologists from six European centers contoured neck and mediastinal clinical target volumes (CTVs) of 2 patients according to the IN and the new INL concepts. The median CTVs, coefficient of variation (COV), and general conformity index (CI) were assessed. The intraclass correlation coefficient (ICC) for reliability of delineations was calculated. RESULTS: All observers agreed that INL is a feasible and practicable delineation concept resulting in stronger interobserver concordance than the IN (mediastinum CI(INL) = 0.39 vs. CI(IN) = 0.28, neck left CI(INL) = 0.33; CI(IN) = 0.18; neck right CI(INL) = 0.24, CI(IN) = 0.14). The COV showed less dispersion and the ICC indicated higher reliability of contouring for INL (ICC(INL) = 0.62, p < 0.05) as for IN (ICC(IN) = 0.40, p < 0.05). CONCLUSION: INL is a practical and feasible alternative to IN resulting in more homogeneous target delineation, and it should be therefore considered as a future target volume concept in PHL.
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- Mavroidis, P., et al.
(författare)
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Dose-Response Relations for Anal Sphincter Regarding Fecal Leakage and Blood or Phlegm in Stools after Radiotherapy for Prostate Cancer Radiobiological Study of 65 Consecutive Patients
- 2005
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Ingår i: Strahlenther Onkol. - 0179-7158. ; 181:5, s. 293-306
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: : The estimation of the parameters that describe the dose-response relations of anal sphincter regarding the clinical endpoints of fecal leakage and blood or phlegm in stools is important in the optimization of prostate cancer radiotherapy. Also, the validity of the relative seriality model for this clinical case needs to be examined by associating the clinical follow-up results with the predicted complication rates. PATIENTS AND METHODS: : In this study, 65 patients who received radiation therapy for clinically localized prostate adenocarcinoma are analyzed. The clinical treatment outcome and the three-dimensional dose distribution delivered to anal sphincter were available for each patient. A questionnaire was used for assessing the clinical bowel and urinary symptoms. A maximum likelihood fitting was performed to calculate the best estimates of the parameters used by the relative seriality model. The clinical utilization of the calculated parameters in predicting anal sphincter complication probabilities was illustrated by applying the best estimate of the parameters to a subset of the patient population. RESULTS: : The estimated values of the parameters for the two clinical endpoints are D (50) = 70.2 Gy, gamma = 1.22, s = 0.35 for fecal leakage and D (50) = 74.0 Gy, gamma = 0.75, s approximately 0 for blood or phlegm in stools. The standard deviations of the parameters were also calculated together with the confidence intervals of the dose-response curves. The analysis proved that the treatment outcome pattern of the patient material can suitably be reproduced by the relative seriality model (probability of finding a worse fit = 60.2%, the area under the receiver operating characteristic curve = 0.72 and 0.69 and chi(2)-test = 0.97 and 0.86, respectively). CONCLUSION: : Fecal leakage is characterized by a medium relative seriality whereas blood or phlegm in stools was found to have strong volume dependence (low relative seriality). Diminishing the biologically effective uniform dose to anal sphincter < 40-45 Gy may significantly reduce the risk of fecal leakage or blood or phlegm in stools for patients irradiated for prostate cancer.
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- Wennstig, Anna-Karin, 1973-, et al.
(författare)
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Risk of coronary stenosis after adjuvant radiotherapy for breast cancer
- 2022
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Ingår i: Strahlentherapie und Onkologie (Print). - : Springer Berlin/Heidelberg. - 0179-7158 .- 1439-099X. ; 198, s. 630-638
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Adjuvant radiotherapy (RT) for breast cancer is associated with an increased risk of ischemic heart disease. We examined the risk of coronary artery stenosis in a large cohort of women with breast cancer receiving adjuvant RT.Methods: A cohort of women diagnosed with breast cancer between 1992 and 2012 in three Swedish health care regions (n = 57,066) were linked to the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) to identify women receiving RT who subsequently underwent a percutaneous coronary intervention (PCI) due to coronary stenosis. Cox regression analyses were performed to examine risk of a coronary intervention and competing risk analyses were performed to calculate cumulative incidence.Results: A total of 649 women with left-sided breast cancer and 494 women with right-sided breast cancer underwent a PCI. Women who received left-sided RT had a significantly higher risk of a PCI in the left anterior descending artery (LAD) compared to women who received right-sided RT, hazard ratio (HR) 1.44 (95% confidence interval [CI] 1.21–1.77, p < 0.001). For the proximal, mid, and distal LAD, the HRs were 1.60 (95% CI 1.22–2.10), 1.38 (95% CI 1.07–1.78), and 2.43 (95% CI 1.33–4.41), respectively. The cumulative incidence of coronary events at 25 years from breast cancer diagnosis were 7.0% in women receiving left-sided RT and 4.4% in women receiving right-sided RT.Conclusion: Implementing and further developing techniques that lower cardiac doses is important in order to reduce the risk of long-term side effects of adjuvant RT for breast cancer.
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- Zanoli, Massimiliano, 1989, et al.
(författare)
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Verification of self-calibration algorithms for phased array applicators
- 2018
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Ingår i: Strahlentherapie und Onkologie. - : Springer Science and Business Media LLC. - 0179-7158 .- 1439-099X.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction In microwave hyperthermia (MW-HT), treatment planning determines the steering parameters for a phased array to yield appropriate tumor coverage and hot-spot suppression. In real HT systems, however, such arrays are subjected to mismatches, which might not be considered in the models used in treatment planning. While certain mismatches can be addressed via channel calibration, those occurring inside the array are more difficult to predict as they can vary during the treatment session itself. The effect of such mismatches can be as relevant as to disrupt the interference pattern. Objectives This contribution proposes self-calibration (SC) as a solution for real-time compensation of various types of mismatches, such as different cable lengths, manufacturing tolerances, patient misplacement and air bubbles in the water bolus. Two SC algorithms have been designed for use with applicator arrays of arbitrary shapes. Materials & Methods The algorithms are based on comparison of simulated and measured S-matrices of the phased array. The extra time delays caused by various mismatches at each channel are then compensated accordingly. The verification of both algorithms includes virtual and experimental models of our neck applicator used in a setup with a patient model and a muscle phantom. The accuracy has been evaluated numerically by comparing the ideal E-field distributions with those obtained by introducing a set of randomly distributed mismatches to the applicator model. The proof-of-principle has then been demonstrated experimentally by means of temperature measurements. Results Results indicate that at least one of the tested SC algorithms converge to the correct compensation solution with performances largely comparable and sometimes even exceeding those typical of an external calibration. Antenna offsets of ±5 mm and air bubbles about 1 cm big are well handled. Improvements can be done with respect to patient misplacement, which is compensated by the algorithm up to ±1 mm. Experimental results confirm the ability of the algorithm to restore focus shape. Conclusion Self-calibration can be a valid solution for mismatch compensation in MW-HT. The potential real-time application of SC makes it a desirable candidate for use in clinical settings.
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