Background: This study aimed to assess the association of 18F-Fluorodeoxyglucose positron-emission-tomography (18F-FDG/PET) and DWI imaging parameters from a primary tumor and their correlations with clinicopathological factors. Methods: We retrospectively analyzed primary tumors in 71 patients with proven HNC. Primary tumor radiological parameters: DWI and FDG, as well as pathological characteristics were analyzed. Spearman correlation coefficient was used to assess the correlation between DWI and FDG parameters, ANOVA or Kruskal–Wallis, independent sample t-test, Mann–Whitney test, and multiple regression were performed on the clinicopathological features that may affect the 18F- FDG and apparent-diffusion coefficient (ADC) of the tumor. Results: No significant correlations were observed between DWI and any of the 18F-FDG parameters (p > 0.05). SUVmax correlated with N-stages (p = 0.023), TLG and MTV correlated with T-stages (p = 0.006 and p = 0.001), and ADC correlated with tumor grades (p = 0.05). SUVmax was able to differentiate between N+ and N− groups (p = 0.004). Conclusions: Our results revealed a non-significant correlation between the FDG-PET and ADC-MR parameters. FDG-PET-based glucose metabolic and DWI-MR-derived cellularity data may represent different biological aspects of HNC.

Our aim was to present different treatment strategies (non-gated [NG], respiratory-gated [RG] and deep inspiration breath-hold [DIBH] technique) of linac-based stereotaxic ablative radiotherapy (SABR) for pancreatic cancer in terms of use of marker, abdominal compression, image quality, and time efficiency. From October 2016 to October 2020 14 patients were treated with VMAT-based SABR (NG: 6/14, 8/14 RG RT including 3/8 DIBH SABR). Treatment verification consisted of 3D/4D CBCTs. For intrafractional tumor visualization (11/14) different type of fiducials were used. The average treatment time was the shortest with NG RT, followed by DIBH and RG RT. However, the best image quality was achieved with DIBH technique. The Krippendorff's agreement test among three independent RTTs showed that DIBH CBCT (Cone Beam CT) can produce sufficient image quality for OARs and can be used to reliably determine OARs position related to safety zone (PRV). Overall, marker-based DIBH SABR with intrafractional tumor visualization appears to be the best technique on linac at present.

Objectives: To determine the feasibility of pre-treatment primary tumor FDG-PET and DWI-MR imaging parameters in predicting HPV status and the second aim was to assess the feasibility of those imaging parameters to predict response to therapy. Material and Methods: We retrospectively analyzed primary tumors in 33 patients with proven OPSCC. PET/MRI was performed before and 6 months after chemo-radiotherapy for assessing treatment response. PET Standardized uptake value (SUVmax), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and apparent diffusion coefficient (ADC) from pre-treatment measurements were assessed and compared to the clinicopathological characteristics (T stages, N stages, tumor grades, HPV and post-treatment follow up). HPV was correlated to the clinicopathological characteristics. Results: ADCmean was significantly lower in patients with HPV+ve than HPV-ev, (P = 0.001), cut off value of (800 +/- 0.44*10-3mm2/s) with 76.9% sensitivity, and 72.2% specificity is able to differentiate between the two groups. No significant differences were found between FDG parameters (SUVmax, TLG, and MTV), and HPV status, (P = 0.873, P = 0.958, and P = 0.817), respectively. Comparison between CR and NCR groups; ADCmean, TLG, and MTV were predictive parameters of treatment response, (P = 0.017, P = 0.013, and P = 0.014), respectively. HPV+ve group shows a higher probability of lymph nodes involvement, (P = 0.006) Conclusion: Our study found that pretreatment ADC of the primary tumor can predict HPV status and treatment response. On the other hand, metabolic PET parameters (TLG, and MTV) were able to predict primary tumor response to therapy.

OBJECTIVE The aim of the study was to evaluate the predictive value of pretreatment positron emission tomography (PET) standardized uptake value (SUVmax), standardized uptake value corrected for lean body mass (SULpeak) value, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) parameters of the primary tumour assessed with PET/computed tomography (CT) in the clinical out-come in patients diagnosed with histopathologically confirmed head and neck squamous cell carcinoma. MATERIALS AND METHODS Retrospective evaluation was performed using PET/CT image datasets of 52 histologically proven head and neck cancer patients in 4 weeks' prior receiving definitive chemo-radiotherapy (CRT). Positron emission tomography /CT was performed before the CRT and 12 weeks after it for response evaluation. Image data was used for target volume delineation and for specify SUVmax, SULpeak, MTV and TLG parameters of the primary tumour. According to the results of the therapeutic response evaluation two patient subgroups were created in relation to the presence or absence of viable tumour. Metabolic data from pre-treatment PET/CT and therapeutic response were correlated using Kruskal-Wallis test. RESULTS After completion of the CRT in 24/52 (46%) cases viable residual tumour was detected on restaging PET/CT, while in 28/52 (54%) patients showed complete remission. For the therapeutic success prediction assessment, we could not find any significant correlation with pre-treatment SUVmax and SULpeak values (P>0.44, P>0.33). Total lesion glycolysis provided nearly significant difference (P=0.052) and MTV had shown significant difference (P=0.001) between the two patient subgroups statistically. CONCLUSION Simple metabolic data (SUVmax and SULpeak) from pretreatment fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT were unable to predict therapeutic response, while volumetric information containing MTV and TLG parameters proved to be more useful, thus their inclusion to risk stratification may also have additional value.

AbstractBackgroundTo determine the usefulness of Diffusion Weighted Imaging (DWI) derived from PET/MRI in discriminating normal from metastatic lymph nodes and the correlation between the metastatic lymph nodes with the grade and the localization of the primary tumor.MethodsRetrospective study of 90 lymph nodes from 90 subjects; 65 patients who had proven histopathological metastatic lymph nodes from (HNSCC) who had undergone18F- PET/MRI for clinical staging and assessment and twenty-five lymph nodes were chosen from 25 healthy subjects. Apparent Diffusion Coefficient (ADC) map was generated from DWI withbvalues (0 and 800 s/mm2). ADC values of the metastatic lymph nodes were calculated and compared to the normal lymph nodes ADC values, ROC was used to determine the best cut-off values to differentiate between the two group. Metastatic lymph nodes ADC mean values were compared to primary tumor grade and localization.ResultsADCmean value of the metastatic lymph nodes in the overall sample (0.899 ± 0.98*10− 3 mm2/sec) was significantly lower than the normal lymph nodes’ ADCmean value (1.267 ± 0.88*10− 3 mm2/sec); (P = 0.001). The area under the curve (AUC) was 98.3%, sensitivity and specificity were 92.3 and 98.6%, respectively, when using a threshold value of (1.138 ± 0.75*10− 3 mm2/sec) to differentiate between both groups. Significant difference was found between metastatic lymph nodes (short-axis diameter < 10 mm), ADCmean (0.898 ± 0.72*10− 3 mm2/sec), and the benign lymph nodes ADCmean, (P = 0.001). No significant difference was found between ADCmean of the metastatic lymph nodes < 10 mm and the metastatic lymph nodes > 10 mm, ADCmean (0.899 ± 0.89*10− 3 mm2/sec), (P = 0.967). No significant differences were found between metastatic lymph nodes ADCmean values and different primary tumor grades or different primary tumor localization, (P > 0.05).ConclusionDWI-ADC is an effective and efficient imaging technique in differentiating between normal and malignant lymph nodes, and might be helpful to discriminate sub-centimeters lymph nodes.Trial registrationThe trial is registered in clinical trials underID:NCT04360993, registration date: 17/04/2020.

Abstract The authors have requested that this preprint be removed from Research Square.

The human brain as an organ has numerous functions; some of them can be visualized by functional imaging techniques (e.g., functional MRI [fMRI] or positron emission tomography). The localization of the appropriate activity clusters requires sophisticated instrumentation and complex measuring protocol. As the inclusion of the activation pattern in modern self-tailored 3D based radiotherapy has notable advantages, this method is applied frequently. Unfortunately, no standardized method has been published yet for the integration of the fMRI data into the planning process and the detailed description of the individual applications is usually missing. Thirteen patients with brain tumors, receiving fMRI based RT planning were enrolled in this study. The delivered dose maps were exported from the treatment planning system and processed for further statistical analysis. Two parameters were introduced to measure the geometrical distance Hausdorff Distance (HD), and volumetric overlap Dice Similarity Coefficient (DSC) of fMRI corrected and not corrected dose matrices as calculated by 3D planning to characterize similarity and/or dissimilarity of these dose matrices. Statistical analysis of bootstrapped HD and DSC data was performed to determine confidence intervals of these parameters. The calculated confidence intervals for HD and DSC were (5.04, 7.09), (0.79, 0.86), respectively for the 40 Gy and (5.2, 7.85), (0.74, 0.83), respectively for the 60 Gy dose volumes. These data indicate that in the case of HD < 5.04 and/or DSC > 0.86, the 40 Gy dose volumes obtained with and without fMRI activation pattern do not show a significant difference (5% significance level). The same conditions for the 60 Gy dose volumes were HD < 5.2 and/or DSC > 0.83. At the same time, with HD > 7.09 and/or DSC < 0.79 for 40 Gy and HD > 7.85 and/or DSC < 0.74 for 60 Gy the impact of fMRI utilization in RT planning is excessive. The fMRI activation clusters can be used in daily RT planning routine to spare activation clusters as critical areas in the brain and avoid their high dose irradiation. Parameters HD (as distance) and DSC (as overlap) can be used to characterize the difference and similarity between the radiotherapy planning target volumes and indicate whether the fMRI delivered activation patterns and consequent fMRI corrected planning volumes are reliable or not.

Purpose: This study aims to evaluate the predictive value of the pretreatment, metabolic, and diffusion parameters of a primary tumor assessed with PET/MR on patient clinical outcomes. Methods: Retrospective evaluation was performed using PET/MR image data sets acquired using the single tracer injection dual imaging of 68 histologically proven head and neck cancer patients 4 weeks before receiving definitive chemoradiotherapy (CRT). PET/MR was performed before the CRT and 12 weeks after the CRT for response evaluation. Image data (PET and MRI diffusion-weighted imaging [DWI]) was used to specify the maximum standard uptake value, the peak lean body mass corrected, SUVmax, the metabolic tumor volume, the total lesion glycolysis (SUVmax, SULpeak, MTV, and TLG), and the mean apparent diffusion coefficient (ADCmean) of the primary tumor. Based on the results of the therapeutic response evaluation, two patient subgroups were created: one with a viable tumor and another without. Metabolic and diffusion data, from the pretreatment PET/MR and the therapeutic response, were correlated using Spearman's correlation coefficient and Wilcoxon's test. Results: After completing the CRT, a viable residual tumor was detected in 36/68 (53%) cases, and 32/68 (47%) patients showed complete remission. However, no significant correlation was found between the pretreatment parameter, ADCmean (p = 0.88), and the therapeutic success. The PET parameters, SUVmax and SULpeak, MTV, and TLG (p = 0.032, p = 0.01, p < 0.0001, p = 0.0004) were statistically significantly different between the two patient subgroups. Conclusion: This study found that MRI-based (ADCmean) data from FDG PET/MR pretreatment could not be used to predict therapeutic response although the PET parameters SUVmax, SULpeak, MTV, and TLG proved to be more useful; thus, their inclusion in risk stratification may also be of additional value.

Our aim was to present our treatment and verification protocols of linear accelerator-based lung and abdominal stereotactic ablative radiotherapy (SABR). During our treatments both the volumetric imaging (3D/4D CBCT/CT) and triggered kV intrafractional tumor motion control could be combined allowing a full control on the whole workflow. The most optimal kV directions from which the tumor is well detectable were defined. Tumor movements measured on cine MRI in treatment position correlated well with the ones on 4D CBCT, thus cine MRI is considered an excellent device to pre-select the appropriate image/treatment verification SABR protocol. In abdominal targets implanted markers and cine MRI are preferred due to limited image quality of CBCT with the current version. In selected lung SABR cases (≥8mm motion) the dose delivery of organs at risk (lungs - GTV, chest wall) could be reduced compared to free breathing conditions, however, the treatment time is at least two-folds higher.

BACKGROUND AND PURPOSE:Radiotherapy plays important role in the complex oncological treatment of glioblastoma multiforme (GBM). The modern 3D radiotherapy treatments are based on cross-sectional CT and MR information, however more attention is being paid to functional hybrid imaging describing the biological and functional morphology of tumor lesions. 18F-DOPA is an amino acid tracer with high specificity and sensitivity, which may play an important role in the precise definition of target volume in the irradiation process of GBM patients. Our study presents the first experiences with 18F-DOPA based PET/CT/MR 3D irradiation planning process.METHODS:In Hungary the 18F-DOPA radiotracer has been available for clinical use since September 2017. Between September 2017 and January 2018, at the Somogy County Kaposi Mór Teaching Hospital Dr. József Baka Diagnostic, Radiation Oncology, Research and Teaching Center 3 histologically verified glioblastoma multiforme patients received 18F-DOPA based 3D irradiation treatment. In the contouring process the native planning CT scanes were fused with the PET/MR series (T1 contrast enhanced, T2 and 18F-DOPA sequences). We defined 18F-DOPA uptake volume (BTV-F-DOPA), the T1 contrast enhanced MRI volume (GTV-T1CE), and the volume of the area covered by oedema on the T2 weighted MRI scan (CTV-oedema) in all patients. We also registered the BTV-F-DOPA volumes not covered by the conventional MR based target volumes.RESULTS:Examining the 3 cases, the average volume of 18F-DOPA tumor was 22.7 cm3 (range 15.3-30.9; SD = 7.82). The average GTV T1 CE was found to be 8.7 cm3 (range 3.8-13.2; SD = 4.70). The mean CTV oedema volume was 40.3 cm3 (range 27.7-57.7; SD = 15.36). A non-overlapping target volume difference (BTV-F-DOPA not covered by CTV oedema area) was 4.5 cm3 (range 1-10.3; SD = 5.05) for PTV definition.CONCLUSION:Based on our results the tumor area defined by the amino acid tracer is not fully identical with the MRI defined T2 oedema CTV. 18F-DOPA defined BTV can modify the definiton of the PTV, and the radiotherapy treatment.

Purpose or ObjectiveReduced-dose protocols have been made available on Varian Edge kV cone beam CT (CBCT) and Halcyon MV CBCT.To assist clinicians in choosing optimal imaging modality for specific patient anatomy, this work compared the imaging dose and positioning accuracy of kV and MV CBCT using various scanning protocols and phantoms.

397 Objectives: PET/MR imaging provides unique opportunity to acquire morphological, functional and metabolic data simultaneously, allowing different biological characteristics visualization of oncologic disorders with one examination. Diffusion weighted imaging (DWI) is a highly emerging advanced MR technique in cancer diagnostics. L-3,4-Dihydroxy-6-[18F]phenylalanine (F-DOPA) PET tracer was initially used for Parkinson imaging, however its neuro-oncologic application is also evolving in the recent years. The aim of our survey was to evaluate F-DOPA uptake and DWI MR parameters in different brain tumors using PET/MR. Methods: 39 F-DOPA PET/MR examinations, performed between September 2017 and November 2018 were retrospectively assessed. Imaging included UTE, T1W, T2W, FLAIR, DWI (b0, b1000) MR sequences and simultaneous PET acquisition, initiated 10 minutes after intravenous injection of 2 MBq/kg F-DOPA tracer. From the DWI MR images ADC maps were generated automatically. A total of 46 lesions were analysed /26 high grade glioma (HGG), 15 low-grade glioma (LGG) and 5 metastatic disorder/. Within the HGG group, a subgroup of glioblastoma multiforme (GBM) disorders was also generated, containing 21 lesions. PET SUVmax and SULpeak, MR DWImax(b1000) and ADCmin parameters were calculated for each lesion using ROI analysis and correlated with World Health Organization (WHO) tumor grade. Association of measured lesional PET and MR parameters were also assessed. Statistics included ANOVA, Tukey post-hoc test and correlation analysis. Results: HGG disorders represented with higher SUVmax, SULpeak and DWImax and lower ADCmin values than low grade gliomas (mean SUVmax: 4.18 vs 2.36, p=0.0001; mean SULpeak: 2.61 vs 1.53, p=0.0005; mean DWImax: 481 vs 228, p

Introduction and aim: The aim of our study was to investigate changes in clinical staging N (lymph node) and M (distant metastasis) in patients who receive PET/CT-based 3D radiotherapy within complex oncological treatment, and compare to conventional cross-sectional imaging staging technique. We also investigated the presence of PET/ CT-detected second tumors and the effect of PET/CT on therapeutic decisions. Method: From the 1st of January 2015 to the 30th of November 2016, 192 patients (n = 192) were treated with PET/CT-based radiation (109 head, 44 lung, 28 rectum and 11 cervical localization) in the Oncoradiology Institute of the Health Center of the University of Kaposvár. All patients received conventional cross-sectional and PET/CT imaging in accordance with the valid investigation protocol. The average time interval between the two cross-sec-tional investigations was 5.2 weeks. Clinical N and M staging was performed on the basis of the classification of the American Joint Committee on Cancer (AJCC) and the Union of International Cancer Control (UICC). Results: By analyzing the clinical stages N and M separately, based on the results of the PET/CT studies, the N stage was changed in 77 cases and the M stage changed in 31 cases. Overall, the PET/CT study resulted in higher clinical stages in 68 (35.4%) patients and lower clinical stages in 14 (7.3%) patients. The treatment plan was changed in 9% of the patients (n = 18) (definitive versus palliative treatment) and the extension of radiotherapy treatment target volume (PTV) was indicated in 20% of the patients (n = 39) due to the change in clinical lymph node status. PET/CT also detected secondary tumors in 15 (8%) patients. Conclusion: Based on our results, the addition of PET/CT to conventional cross-sectional staging imaging permits a more accurate clinical classification of N and M stages and significantly influences therapeutic decisions. PET/CT imaging also provides a great help in detecting occult second tumors. The results of our Institute harmonize with the international data available in the literature.

Abstract: Hungary’s first and still only multimodality PET/MR device is operating in the Health Center of Kaposvár University. The aim of our review article is to present the current Hungarian PET/MR imaging application opportunities, our available initial experiences with this novel multimodality imaging technique in malignant and non-malignant diseases and further potential targeted clinical fields of use are also addressed. Orv Hetil. 2018; 159(34): 1375–1384.

Hungary's first and still only multimodality PET/MR device is operating in the Health Center of Kaposvar University. The aim of our review article is to present the current Hungarian PET/MR imaging application opportunities, our available initial experiences with this novel multimodality imaging technique in malignant and non-malignant diseases and further potential targeted clinical fields of use are also addressed.