Biologically conformal treatment: biomarkers and functional imaging in radiation oncology (original) (raw)
Related papers
Biological imaging in radiation therapy: role of positron emission tomography
Physics in Medicine and Biology, 2009
In radiation therapy (RT), staging, treatment planning, monitoring and evaluation of response are traditionally based on computed tomography (CT) and magnetic resonance imaging (MRI). These radiological investigations have the significant advantage to show the anatomy with a high resolution, being also called anatomical imaging. In recent years, so called biological imaging methods which visualize metabolic pathways have been developed. These methods offer complementary imaging of various aspects of tumour biology. To date, the most prominent biological imaging system in use is positron emission tomography (PET), whose diagnostic properties have clinically been evaluated for years. The aim of this review is to discuss the valences and implications of PET in RT. We will focus our evaluation on the following topics: the role of biological imaging for tumour tissue detection/delineation of the gross tumour volume (GTV) and for the visualization of heterogeneous tumour biology. We will discuss the role of fluorodeoxyglucose-PET in lung and head and neck cancer and the impact of amino acids (AA)-PET in target volume delineation of brain gliomas. Furthermore, we summarize the data of the literature about tumour hypoxia and proliferation visualized by PET. We conclude that, regarding treatment planning in radiotherapy, PET offers advantages in terms of tumour delineation and the description of biological processes. However, to define the real impact of biological imaging on clinical outcome after radiotherapy, further experimental, clinical and cost/benefit analyses are required.
Medical Physics, 2019
The use of positron emission tomography (PET) in radiation therapy (RT) is rapidly increasing in the areas of staging, segmentation, treatment planning, and response assessment. The most common radiotracer is 18 F-fluorodeoxyglucose ([ 18 F]FDG), a glucose analog with demonstrated efficacy in cancer diagnosis and staging. However, diagnosis and RT planning are different endeavors with unique requirements, and very little literature is available for guiding physicists and clinicians in the utilization of [ 18 F]FDG-PET in RT. The two goals of this report are to educate and provide recommendations. The report provides background and education on current PET imaging systems, PET tracers, intensity quantification, and current utilization in RT (staging, segmentation, image registration, treatment planning, and therapy response assessment). Recommendations are provided on acceptance testing, annual and monthly quality assurance, scanning protocols to ensure consistency between interpatient scans and intrapatient longitudinal scans, reporting of patient and scan parameters in literature, requirements for incorporation of [ 18 F]FDG-PET in treatment planning systems, and image registration. The recommendations provided here are minimum requirements and are not meant to cover all aspects of the use of [ 18 F]FDG-PET for RT.
Positron Emission Tomography (PET) in Oncology
Cancers, 2014
Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%-15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later.
Positron emission tomography in radiation treatment planning: the potential of metabolic imaging
Radiologic clinics of North America, 2013
Treatment planning and delivery of radiation therapy has benefited from new technology and techniques. Given the convergence of the improved ability to image active tumor and the delivery of radiation to very specific targets, the implications for a tighter integration of positron emission tomography (PET) imaging with radiation treatment planning are apparent. This article summarizes developments in radiation therapy technology and the application of various PET tracers in diseases treated by radiation therapy, and looks to future possibilities of combining them.
European Journal of Internal Medicine, 2014
Positron emission tomography (PET) was developed in the mid-1970, and its initial applications were for heart and brain imaging research. Nowadays, this technology is aimed mainly at staging or restaging tumours as it allows the assessment of biochemical processes that are either specific or associated with tumour biology. The full appreciation of PET potentials and limitations among general practitioners and internists cannot be considered achieved and the appropriate use of PET especially when coupled to X-ray computed tomography (CT) is still suboptimal. The majority of PET studies rely on the use of fluorodeoxyglucose labelled with fluorine-18 (FDG), which is a radiopharmaceutical specific for glucose transport and metabolism. PET with FDG is amenable for studying most type of tumours, including those of the head and neck, lung, oesophagus, colo-rectal, gastrointestinal stromal tumours, pancreas, some types of lymphomas and melanoma, whereas in some tumours, including those of the reproductive system, brain, breast and bones, there is a limited role for PET and there is no substantial role for FDG-PET for the bronchoalveolar, hepatocellular, urinary system, testicular, neuroendocrine, carcinoids and adrenal tumours, differentiated thyroid cancers, and several subtypes of malignant lymphoma. Thus, the limits of FDG have stimulated the use and development of other radiopharmaceuticals. These tracers represent the opportunity for expanding the use of PET to other areas in oncology in the near future.
The impact of functional imaging on radiation medicine
Radiation Oncology, 2008
Radiation medicine has previously utilized planning methods based primarily on anatomic and volumetric imaging technologies such as CT (Computerized Tomography), ultrasound, and MRI (Magnetic Resonance Imaging). In recent years, it has become apparent that a new dimension of non-invasive imaging studies may hold great promise for expanding the utility and effectiveness of the treatment planning process. Functional imaging such as PET (Positron Emission Tomography) studies and other nuclear medicine based assays are beginning to occupy a larger place in the oncology imaging world. Unlike the previously mentioned anatomic imaging methodologies, functional imaging allows differentiation between metabolically dead and dying cells and those which are actively metabolizing. The ability of functional imaging to reproducibly select viable and active cell populations in a non-invasive manner is now undergoing validation for many types of tumor cells. Many histologic subtypes appear amenable to this approach, with impressive sensitivity and selectivity reported.
Quantitative FDG PET Assessment for Oncology Therapy
Cancers, 2021
Positron emission tomography (PET) has unique characteristics for quantitative assessment of tumour biology in vivo. Accumulation of F-18 fluorodeoxyglucose (FDG) may reflect tumour characteristics based on its metabolic activity. Quantitative assessment of FDG uptake can often be applied for treatment monitoring after chemotherapy or chemoradiotherapy. Numerous studies indicated biochemical change assessed by FDG PET as a more sensitive marker than morphological change estimated by CT or MRI. In addition, those with complete metabolic response after therapy may show better disease-free survival and overall survival than those with other responses. Assessment of metabolic change may be performed using absolute FDG uptake in the tumour (standardized uptake value: SUV). In addition, volumetric parameters such as metabolic tumour volume (MTV) have been introduced for quantitative assessment of FDG uptake in tumour. More recently, radiomics approaches that focus on image-based precision...
Journal of translational medicine, 2015
This study aims to assess the effect of radiation treatment on the tumour vasculature and its downstream effects on hypoxia and choline metabolism using a multimodal approach in the murine prostate tumour model CWR22. Functional parameters derived from Positron Emission Tomography (PET)/Computer Tomography (CT) with (18)F-Fluoromisonidazole ((18)F-FMISO) and (18)F-Fluorocholine ((18)F-FCH) as well as Dynamic Contrast-Enhanced Ultrasound (DCE-US) were employed to determine the relationship between metabolic parameters and microvascular parameters that reflect the tumour microenvironment. Immunohistochemical analysis was employed for validation. PET/CT and DCE-US were acquired pre- and post-treatment, at day 0 and day 3, respectively. At day 1, radiation treatment was delivered as a single fraction of 10 Gy. Two experimental groups were tested for treatment response with (18)F-FMISO and (18)F-FCH. The maximum Standardized Uptake Values (SUVmax) and the mean SUV (SUVmean) for the (18)F...