Katalin Hideghéty

Individual Positioning: A Comparative Study of Adjuvant Breast Radiotherapy in the Prone Versus Supine Position

PURPOSE To study breast radiotherapy in the prone vs. supine positions through dosimetry and clinical implementation. METHODS AND MATERIALS Conformal radiotherapy plans in 61 patients requiring only breast irradiation were developed for both the prone and supine positions. After evaluation of the of the first 20 plan pairs, the patients were irradiated in the prone or supine position in a randomized fashion. These cases were analyzed for repositioning accuracy and skin reactions related to treatment position and patient characteristics. RESULTS The planning target volume covered with 47.5-53.5 Gy in the prone vs. the supine position was 85.1% +/- 4.2% vs. 89.2 +/- 2.2%, respectively (p < 0.0001). Radiation exposure of the ipsilateral lung, expressed in terms of the mean lung dose and the V(20Gy), was dramatically lower in the prone vs. supine position (p < 0.0001), but the doses to the heart did not differ. There was no difference in the need to correct positioning during radiotherapy, but the extent of displacement was significantly higher in the prone vs. supine position (p = 0.021). The repositioning accuracy in the prone position exhibited an improvement over time and did not depend on any patient-related parameters. Significantly more radiodermatitis of Grade 1-2 developed following prone vs. supine irradiation (p = 0.025). CONCLUSIONS Conformal breast radiotherapy is feasible in the prone position. Its primary advantage is the substantially lower radiation dose to the ipsilateral lung. The higher dose inhomogeneity and increased rate of Grade 1-2 skin toxicity, however, may be of concern.

Combination of unsaturated fatty acids and ionizing radiation on human glioma cells: cellular, biochemical and gene expression analysis

BackgroundBased on previous observations a potential resort in the therapy of the particularly radioresistant glioma would be its treatment with unsaturated fatty acids (UFAs) combined with irradiation.MethodsWe evaluated the effect of different UFAs (arachidonic acid (AA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA) and oleic acid (OA)) on human U87 MG glioma cell line by classical biochemical end-point assays, impedance-based, real-time cellular and holographic microscopic analysis. We further analyzed AA, DHA, and GLA at morphological, gene and miRNA expression level.ResultsCorresponding to LDH-, MTS assays and real-time cytoxicity profiles AA, DHA, and GLA enhanced the radio sensitivity of glioma cells. The collective application of polyunsaturated fatty acids (PUFAs) and irradiation significantly changed the expression of EGR1, TNF-α, NOTCH1, c-MYC, TP53, HMOX1, AKR1C1, NQO1, while up-regulation of GADD45A, EGR1, GRP78, DDIT3, c-MYC, FOSL1 were recorded both in response to PUFA treatment or irradiation alone. Among the analyzed miRNAs miR-146 and miR-181a were induced by DHA treatment. Overexpression of miR-146 was also detected by combined treatment of GLA and irradiation.ConclusionsBecause PUFAs increased the radio responsiveness of glioma cells as assessed by biochemical and cellular assays, they might increase the therapeutic efficacy of radiation in treatment of gliomas. We demonstrated that treatment with DHA, AA and GLA as adjunct to irradiation up-regulated the expression of oxidative-stress and endoplasmic reticulum stress related genes, and affected NOTCH1 expression, which could explain their additive effects.

Lipidomic analysis reveals a radiosensitizing role of gamma-linolenic acid in glioma cells

Previous studies have demonstrated that gamma-linolenic acid (GLA) is effective against glioma cells under both in vitro and in vivo conditions. In the present study we determined how GLA alone or in combination with irradiation alters the fatty acid (FA) and lipid profiles, the lipid droplet (LD) content, the lipid biosynthetic gene expression and the apoptosis of glioma cells. In GLA-treated cells direct correlations were found between the levels of various FAs and the expression of the corresponding FA biosynthetic genes. The total levels of saturated and monosaturated FAs decreased in concert with the down-regulation of FASN and SCD1 gene expression. Similarly, decreased FADS1 gene expression was paralleled by lowered arachidonic acid (20:4 n-6) and eicosapentaenoic acid (20:5 n-3) contents, while the down-regulation of FADS2 expression was accompanied by a diminished docosahexaenoic acid (22:6 n-3) content. Detailed mass spectrometric analyses revealed that individual treatments gave rise to distinct lipidomic fingerprints. Following uptake, GLA was subjected to elongation, resulting in dihomo-gamma-linolenic acid (20:3 n-6, DGLA), which was used for the synthesis of the LD constituent triacylglycerols and cholesteryl esters. Accordingly, an increased number of LDs were observed in response to GLA administration after irradiation. GLA increased the radioresponsiveness of U87 MG cells, as demonstrated by an increase in the number of apoptotic cells determined by FACS analysis. In conclusion, treatment with GLA increased the apoptosis of irradiated glioma cells, and GLA might therefore increase the therapeutic efficacy of irradiation in the treatment of gliomas.

Evaluation of boron neutron capture effects in cell culture using sulforhodamine-B assay and a colony assay

PURPOSE The purpose of this study was to find an in vitro method for determining the cytotoxicity of boronated drugs as well as their potential suitability for neutron capture therapy. MATERIALS AND METHODS The survival of human melanoma cells has been determined by a colony assay and the sulforhodamine-B assay after X-irradiation and irradiation with fast d(14) + Be-neutrons using the boronated compound borocaptate sodium (BSH). The cytotoxic effects of BSH have been studied using both methods. RESULTS Under well-defined experimental conditions, and after a sufficient amount of time for the expression of radiation damage, the results of the sulforhodamine-B assay are qualitatively comparable with the results of the colony assay. CONCLUSION The sulforhodamine-B assay is suitable for the screening of compounds for potential use in neutron capture therapy because it is a fast and efficient method that is reproducible and technically advantageous.

Development of a small-animal focal brain irradiation model to study radiation injury and radiation-injury modifiers.

Abstract Purpose: Our aim was to establish an effective small-animal focal brain radiation model for research on brain injuries. Material and methods: Groups of up to six rats were exposed to a range of doses from 120–40 Gy, at 10 intervals of a 6 MeV electron beam. Open-field motor functions and water maze learning-memory tests were performed after the irradiation at two-week intervals. Morphological changes were detected through repeated magnetic resonance imaging (MRI) monthly and were compared with the histopathological findings to determine if they predicted late microscopic changes. Results: The development of necrosis proved to be dose-dependent. 120 Gy resulted in serious deterioration within 4 weeks in all rats. Localized necrosis in one hemisphere was detected 2 months after the irradiation with ≥ 70 Gy, and 3 months after 40–60 Gy consistent for all animals. The Morris water maze (MWM) tests proved to be the most sensitive tool for the early detection of a brain functional impairment. MRI screening provided useful information on the development of radiation necrosis, which defined the time point for histological examinations. Conclusions: The described method permits accurate dose delivery to a definite part in one hemisphere of the brain for six rats at a time. Following complex examinations, a dose of 40 Gy and a follow-up time of 4 months are proposed for investigations on neuroradiation modifiers.

A prospective study of supine versus prone positioning and whole-body thermoplastic mask fixation for craniospinal radiotherapy in adult patients

PURPOSE To evaluate neuroaxis irradiation for adults in the supine position using head body thermoplastic mask fixation, from the aspects of dose distribution, patient comfort and set-up accuracy. METHODS AND MATERIALS Nine of the 12 adult patients were positioned for craniospinal axis irradiation in both prone and supine positions. After mask fixation and planning CTs in both positions, a questionnaire relating to the comfort was completed. The doses to the target and to the organs at risk of the 3D conformal plans in the supine and prone positions were compared. Portal images of all 12 patients irradiated in the supine position were evaluated, the van Herk formulas being used to calculate the systemic and random errors. RESULTS No significant difference was found between the prone and supine positions target coverage, the dose homogeneity and the dose to the organs at risk. The supine position was considered more comfortable by the patients (scores of 2.8 versus 4.29), with a vector random error of 3.27 mm, and a systematic error of 0.32 mm. The largest random set-up error was observed in the lateral direction: 4.83 mm. CONCLUSIONS The more comfortable supine position is recommended for craniospinal irradiation in adult patients. Whole-body thermoplastic mask immobilization provides excellent repositioning accuracy.

Peripheral inflammatory activation after hippocampus irradiation in the rat

Abstract Purpose: To detect the possible biochemical signs of inflammatory activation in the peripheral circulation in a rodent model of hippocampus irradiation, and to examine the effects of L-alpha-glycerylphosphorylcholine (GPC) in this experimental protocol. Materials and methods: Anesthetized Sprague-Dawley rats were subjected to 40 Gy cobalt irradiation of both hemispheres of the hippocampus, with or without GPC treatment (50 mg/kg intravenously (i.v.), 5 min before the irradiation, n = 6, each). A third group (n = 6) served as saline-treated control. Blood samples were obtained 3 h after the end of irradiation in order to examine the changes in plasma histamine, tumor necrosis factor-alpha (TNF-α), interleukin 1-beta, interleukin 6 (IL-6) and interleukin 10 (IL-10); liver tissue samples were taken to determine adenosine triphosphate (ATP) concentrations. Results: The hepatic ATP levels were significantly declined, while plasma concentrations of circulating TNF-α, IL-6, IL-10 and histamine were significantly increased after hippocampus irradiation. GPC treatment significantly reduced the irradiation-induced release of cytokines and histamine, and the liver ATP level was maintained at the control value. Conclusions: Targeted brain irradiation produced measurable pro- and anti-inflammatory cytokine changes in the systemic circulation. GPC supplementation provides significant protection against irradiation-induced peripheral pro-inflammatory activation and ATP depletion.

Volumetric response of intracranial meningioma after photon or particle irradiation.

Abstract Background: Meningiomas are usually slow growing, well circumscribed intracranial tumors. In symptom-free cases observation with close follow-up imaging could be performed. Symptomatic meningiomas could be surgically removed and/or treated with radiotherapy. The study aimed to evaluate the volumetric response of intracranial meningiomas at different time points after photon, proton, and a mixed photon and carbon ion boost irradiation. Patients and methods: In Group A 38 patients received proton therapy (median dose: 56 GyE in 1.8–2 GyE daily fractions) or a mixed photon/carbon ion therapy (50 Gy in 2 Gy daily fractions with intensity modulated radiotherapy (IMRT) and 18 GyE in 3 GyE daily dose carbon ion boost). Thirty-nine patients (Group B) were treated by photon therapy with IMRT or fractionated stereotactic radiotherapy technique (median dose: 56 Gy in 1.8–2 Gy daily fractions). The delineation of the tumor volume was based on the initial, one- and two-year follow-up magnetic resonance imaging and these volumes were compared to evaluate the volumetric tumor response. Results: Significant tumor volume shrinkage was detected at one- and at two-year follow-up both after irradiation by particles and by photons. No significant difference in tumor volume change was observed between photon, proton or combined photon plus carbon ion boost treated patients. WHO grade and gender appear to be determining factors for tumor volume shrinkage. Conclusion: Significant volumetric shrinkage of meningiomas could be observed independently of the applied radiation modality. Long-term follow-up is recommended to evaluate further dynamic of size reduction and its correlation with outcome data.

Novel real‑time cell analysis platform for the dynamic monitoring of ionizing radiation effects on human tumor cell lines and primary fibroblasts

Translational research in radiation oncology is important for the detection of adverse radiation effects, cellular responses, and radiation modifications, and may help to improve the outcome of radiation therapy in patients with cancer. The present study aimed to optimize and validate a real‑time label‑free assay for the dynamic monitoring of cellular responses to ionizing radiation. The xCELLigence system is an impedance‑based platform that provides continuous information on alterations in cell size, shape, adhesion, proliferation, and survival. In the present study, various malignant human primary fibroblast cells (U251, GBM2, MCF7, A549, HT‑29) were exposed to 0, 5 and 10 Gy of Cobalt60 radiation. As well as the xCELLigence system, cell survival and proliferation was evaluated using the following conventional end‑point cell‑based methods: Clonogenic, MTS, and lactate dehydrogenase assays, and apoptosis was detected by fluorescence‑activated cell sorting. The effects of ionizing radiation were detected for each cell line using impedance monitoring. The real‑time data correlated with the colony forming assay results. At low cell densities (1,000‑2,000 cells/well) the impedance‑based method was more accurate at monitoring dose‑dependent changes in the malignant human primary fibroblast cell lines, as compared with the end‑point assays. The results of the present study demonstrated that the xCELLigence system may be a reliable and rapid diagnostic method for the monitoring of dynamic cell behavior following radiation. In addition, the xCELLigence system may be used to investigate the cellular mechanisms underlying the radiation response, as well as the time‑dependent effects of radiation on cell proliferation and viability.

The role of Positron Emission Tomography/Computer Tomography (PET/CT) in the diagnosis, staging, characterization, and therapy of breast cancer

PET or PET/CT mostly utilizing the tracer [18F]fluorodeoxyglucose (18FDG) are unique imaging methods for the detection of breast cancers with increased glucolytic activity. PET/CT simultaneously provides anatomic and metabolic information by detecting increased glucose uptake. PET/CT may provide extra information on stage that can be utilized in certain cases during treatment decision making. PET/CT is a very sensitive imaging option to detect lymph node involvement or distant metastasis for which information is needed in selected cases. In the neoadjuvant or metastatic setting, PET or PET/CT may serve as a valuable noninvasive option for investigating chemosensitivity and monitoring the effectiveness of systemic therapy. Its use, however, should be reserved for particular cases with diagnostic uncertainty in the routine management of breast cancer.Molecular imaging with non-FDG PET tracers developed using advanced molecular and cell biology techniques widens the possibility to study the pathological molecular events and processes in breast cancer, and may be used for the detection of key molecules to be targeted by pharmaceutical interventions; the method provides new possibility to evaluate novel drugs.