Assessment of tumour size in PET/CT lung cancer studies: PET- and CT-based methods compared to pathology

BACKGROUND: Positron emission tomography (PET) may be useful for defining the gross tumour volume for radiation treatment planning and for response monitoring of non-small cell lung cancer (NSCLC) patients. The purpose of this study was to compare tumour sizes obtained from CT- and various more commonly available PET-based tumour delineation methods to pathology findings. METHODS: Retrospective non-respiratory gated whole body [(18)F]-fluoro-2-deoxy-D-glucose PET/CT studies from 19 NSCLC patients were used. Several (semi-)automatic PET-based tumour delineation methods and manual CT-based delineation were used to assess the maximum tumour diameter. RESULTS: 50%, adaptive 41% threshold-based and contrast-oriented delineation methods showed good agreement with pathology after removing two outliers (R(2)=0.82). An absolute SUV threshold of 2.5 also showed a good agreement with pathology after the removal of 5 outliers (R(2): 0.79), but showed a significant overestimation in the maximum diameter (19.8 mm, p<0.05). Adaptive 50%, relative threshold level and gradient-based methods did not show any outliers, provided only small, non-significant differences in maximum tumour diameter (<4.7 mm, p>0.10), and showed fair correlation (R(2)>0.62) with pathology. Although adaptive 70% threshold-based methods showed underestimation compared to pathology (36%), it provided the best precision (SD: 14%) together with good correlation (R(2)=0.81). Good correlation between CT delineation and pathology was observed (R(2)=0.77). However, CT delineation showed a significant overestimation compared with pathology (3.8 mm, p<0.05). CONCLUSIONS: PET-based tumour delineation methods provided tumour sizes in agreement with pathology and may therefore be useful to define the (metabolically most) active part of the tumour for radiotherapy and response monitoring purposes

Магнитный контроль параметров ферромагнитных объектов методом высших гармоник

В данной работе объектом исследования являются контрольные образцы тороидальной формы из ферромагнитных сталей различных марок, изготовленные согласно ГОСТ 8.377-80, магнитные параметры которых исследуются с помощью разработанной многопараметровой установки для измерения магнитных характеристик MS-1.In this work, the object of the study is the control samples of toroidal shape of ferromagnetic steels of different brands, made according to GOST 8.377-80, the magnetic parameters of which are investigated using the developed multiparameter installation for measuring the magnetic characteristics of MS-1

Comparison of CT and PET-CT based planning of radiation therapy in locally advanced pancreatic carcinoma

Abstract Background To compare computed tomography (CT) with co-registered positron emission tomography-computed tomography (PET-CT) as the basis for delineating gross tumor volume (GTV) in unresectable, locally advanced pancreatic carcinoma (LAPC). Methods Fourteen patients with unresectable LAPC had both CT and PET images acquired. For each patient, two three-dimensional conformal plans were made using the CT and PET-CT fusion data sets. We analyzed differences in treatment plans and doses of radiation to primary tumors and critical organs. Results Changes in GTV delineation were necessary in 5 patients based on PET-CT information. In these patients, the average increase in GTV was 29.7%, due to the incorporation of additional lymph node metastases and extension of the primary tumor beyond that defined by CT. For all patients, the GTVCT versus GTVPET-CT was 92.5 ± 32.3 cm3 versus 104.5 ± 32.6 cm3 (p = 0.009). Toxicity analysis revealed no clinically significant differences between two plans with regard to doses to critical organs. Conclusion Co-registration of PET and CT information in unresectable LAPC may improve the delineation of GTV and theoretically reduce the likelihood of geographic misses.</p

Comparative methods for PET image segmentation in pharyngolaryngeal squamous cell carcinoma

Several methods have been proposed for the segmentation of ¹⁸F-FDG uptake in PET. In this study, we assessed the performance of four categories of ¹⁸F-FDG PET image segmentation techniques in pharyngolaryngeal squamous cell carcinoma using clinical studies where the surgical specimen served as the benchmark

PET imaging of hypoxia using [F-18]HX4: a phase I trial

 Download the images using these instructions and this DOI : 10.1007/s00259-010-1437-x Background and purposeNon-invasive PET imaging of tumour hypoxia could help in the selection of those patients who could benefit from chemotherapy or radiation with specific antihypoxic treatments such as bioreductive drugs or hypoxic radiosensitizers. In this phase I trial, we aimed to determine the toxicity of [18F]HX4, a member of the 2-nitroimidazole family, at different dose levels. The secondary aim was to analyse image quality related to the HX4 dose and the timing of imaging.MethodsPatients with a..

Clinical development of new drug-radiotherapy combinations.

In countries with the best cancer outcomes, approximately 60% of patients receive radiotherapy as part of their treatment, which is one of the most cost-effective cancer treatments. Notably, around 40% of cancer cures include the use of radiotherapy, either as a single modality or combined with other treatments. Radiotherapy can provide enormous benefit to patients with cancer. In the past decade, significant technical advances, such as image-guided radiotherapy, intensity-modulated radiotherapy, stereotactic radiotherapy, and proton therapy enable higher doses of radiotherapy to be delivered to the tumour with significantly lower doses to normal surrounding tissues. However, apart from the combination of traditional cytotoxic chemotherapy with radiotherapy, little progress has been made in identifying and defining optimal targeted therapy and radiotherapy combinations to improve the efficacy of cancer treatment. The National Cancer Research Institute Clinical and Translational Radiotherapy Research Working Group (CTRad) formed a Joint Working Group with representatives from academia, industry, patient groups and regulatory bodies to address this lack of progress and to publish recommendations for future clinical research. Herein, we highlight the Working Group's consensus recommendations to increase the number of novel drugs being successfully registered in combination with radiotherapy to improve clinical outcomes for patients with cancer.National Institute for Health ResearchThis is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/nrclinonc.2016.7

High-dose hyperfractionated accelerated radiotherapy in non-small cell lung cancer

The observation that improved local tumour control also results in increased survival rates, even in a disease such as non-small cell lung cancer (NSCLC), has fuelled the interest in strategies aimed at local tumour eradication. It has been demonstrated that a clear dose-response relationship exists for radiotherapy, i.e. higher doses of radiation lead to increased local tumour control. However, prolongation of the overall treatment time beyond 4-5 weeks renders radiotherapy less effective because of increased proliferation of tumour cells. It is therefore of interest to deliver as high doses as possible in short overall treatment times. An extreme example of this strategy is stereotactic body radiotherapy (SBRT), where a few large radiation doses, equalling very high biological doses, delivered in a short overall treatment time has resulted in at least 90% tumour control in stage I NSCLC. However, when large volumes or critical normal structures such as the main bronchi are in the high-dose radiation volumes, more extensive fractionation schedules have been used, such as 70 Gy in 35 daily fractions of 2 Gy. As the overall treatment time than exceeds 4-5 weeks, hyperfractionated radiotherapy schedules have been introduced, which all delivered 2-3 relatively small fractions per day to total doses that are similar to the so-called standard regimen. Several randomized phase III trials and a meta-analysis based on individual patient data have demonstrated a superior 5-year survival with this strategy, without increased side effects. Our group has also shown that individualised hyperfractionated accelerated radiotherapy (INDAR) makes treatment with curative intent even in patients with large tumour volumes possible with few important side effects. Early results of INDAR with concurrent chemotherapy or with cetuximab are promising