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Introduction: Molecular Imaging in Oncology
MOLECULAR IMAGING IN ONCOLOGY
Introduction: Molecular Imaging in Oncology
T
he articles in this issue of Seminars in Oncology were assembled to overview the current state of functional and molecular imaging developments targeting enhancements in cancer diagnosis, monitoring, and guiding treatment options. The issue is thoughtfully previewed in the introductory chapter, “The evolving role of imaging in cancer: current state and future challenges,” by Luke J. Higgins and Martin G. Pomper. Although most clinical diagnostic imaging studies employ anatomic techniques such as computed tomography (CT) and magnetic resonance imaging (MRI), much of radiology research currently focuses on adapting these conventional methods to physiologic imaging, as well as on introducing new techniques and probes for studying processes at the cellular and molecular level in vivo. The addition of molecular imaging to conventional imaging approaches promises to provide a critical foundation for personalized cancer therapy. In the introductory chapter and throughout the issue, we strive to emphasize those imaging strategies that show the most immediate likelihood for clinical translation. Vanderbilt University researcher Yankeelov and colleagues provide an overview the role of MRI biomarkers in the management of cancer patients. They provide a clear, crisp explanation of MRI technology and key areas of ongoing and potential development. They include examples of two MRI methods, diffusion imaging and dynamic contrast-enhanced MRI, that recently have been incorporated into clinical trials of treatment response in solid tumors. Limitations and future research directions required for these techniques to gain greater acceptance and to have their maximum impact also are reviewed. Kristine Glunde and Zaver M. Bhujwalla at The Johns Hopkins University review the use of magnetic resonance spectroscopy (MRS) in cancer detection. They focus on noninvasive MRS and spectroscopic imaging (MRSI) and their roles in future personalized medicine in cancer. Diagnosis, the identification of the most effective treatment, monitoring treatment delivery, and response to treatment are some of the broad areas in which MRS techniques can be integrated to improve treatment outcomes. Alexei Bogdanov Jr and Mary L. Mazzanti at the University of Massachusetts discuss the molecular MRI contrast agents for the detection of cancer. Current efforts are directed toward developing a variety of MRI contrast agents with molecular specificities to the growing arSeminars in Oncology, Vol 38, No 1, February 2011, pp 1-2
mamentarium of diagnostic probes capable of changing local proton relaxation times as a consequence of specific contrast agent binding to cell surface receptors or extracellular matrix components. They review the most notable examples, illustrating major trends in the development of specific probes for high-resolution imaging in molecular oncology. Zhu and coworkers at Emory University address metabolic PET imaging in cancer detection and therapy response. Tumor imaging with positron emission tomography (PET) with fluorodeoxyglucose (FDG) FDGPET has been most widely used to improve the diagnosis and subsequent treatment of cancers. In addition, PET imaging using amino acid analogs has shown significant potential for tumor detection in organ sites with undesirable FDG-PET background (eg, methionine-PET and FACBC-PET). Kai Chen and Xiaoyuan Chen at the National Institutes of Health review the PET imaging beyond metabolic PET; over the last decade, numerous target-specific PET tracers have been developed and evaluated in preclinical and clinical studies. This review provides an overview of the current status and trends in the development of nonmetabolic PET probes in oncology and their application in the investigation of cancer biology. Brandon and colleagues at Emory University discuss the role of singlephoton emission computed tomography (SPECT) and SPECT/CT in oncologic imaging. SPECT has shown critical utility for cancer detection despite poor resolution of clinical scanners, eg, molecular breast imaging (MBI) technology, in sentinel node detection. As more disease-specific imaging agents become available, the role of SPECT/CT in the new paradigms of molecular imaging for personalized medicine will expand. They review established and emerging uses of SPECT/CT in a wide variety of oncologic diseases, as well as radiation exposure issues. The interdisciplinary team of Hadjipanayis et al (Emory University, University of Florida, Gainesville, and Dartmouth-Hitchcock Medical Center) discusses both current and future clinical applications for optical imaging, spanning the spectrum of cancer screening to intraoperative surgical guidance. Optical imaging is an inexpensive, fast, and sensitive imaging approach for noninvasively detecting human cancers in locations accessible to an optical imaging device. The use of optical imaging is now being applied in the clinic and 1
2
operating room for the localization and resection of malignant tumors in addition to screening for cancer. Additionally, Carl J. D’Orsi and Mary S. Newell at Emory University review the front line of screening for breast cancer including digital mammography, tomosynthesis, MRI, and ultrasound. In addition, they tackle the difficult topic of the risk-benefit assessment of screening mammography for women in the 40- to 49year age group. Lam and colleagues from the University of California at Davis describe improvements in CT technology and other factors that have contributed to an increase in the use of CT in the United States in recent years. The purpose of this review is to evaluate trends in CT use in cancer surveillance, especially among pediatric patients. Feleppa and coworkers at Riverside Research Institute, New York, review the use of quantitative ultrasound (QUS) in cancer imaging. Ultrasound is a relatively inexpensive, portable, and versatile imaging modality that has a broad range of clinical uses, especially in consideration of recent technology developments. This chapter discusses the attributes of QUSbased methods for imaging cancers and providing an improved means of detecting and assessing tumors. Kevin A. Smith and Hyun S. Kim at Emory University address advances in interventional radiology and image-
H. Shim and C.C. Meltzer
guided medicine for the cancer patient. Over the past three decades, technological advances have allowed transitioning from a role of diagnosis and surveillance to using imaging to guide minimally invasive therapies for an expanding range of oncology patients. Imageguided biopsy or minimally invasive therapies reduces the morbidity and cost associated with conventional surgical approaches. This chapter highlights the current trend of increasingly integrating image-guided interventions into oncologic care. In this issue Seminars, we review the current oncologic application of various imaging technologies and their benefits and shortfalls. We hope you will find this volume informative, and perhaps it may serve as a roadmap for additional applications of molecular, functional imaging to improve the diagnosis and subsequent treatment of cancers.
Hyunsuk Shim, PhD Carolyn C. Meltzer, MD Department of Radiology Emory University Atlanta, GA Guest Editors
Introduction: Molecular Imaging in Oncology
T
he articles in this issue of Seminars in Oncology were assembled to overview the current state of functional and molecular imaging developments targeting enhancements in cancer diagnosis, monitoring, and guiding treatment options. The issue is thoughtfully previewed in the introductory chapter, “The evolving role of imaging in cancer: current state and future challenges,” by Luke J. Higgins and Martin G. Pomper. Although most clinical diagnostic imaging studies employ anatomic techniques such as computed tomography (CT) and magnetic resonance imaging (MRI), much of radiology research currently focuses on adapting these conventional methods to physiologic imaging, as well as on introducing new techniques and probes for studying processes at the cellular and molecular level in vivo. The addition of molecular imaging to conventional imaging approaches promises to provide a critical foundation for personalized cancer therapy. In the introductory chapter and throughout the issue, we strive to emphasize those imaging strategies that show the most immediate likelihood for clinical translation. Vanderbilt University researcher Yankeelov and colleagues provide an overview the role of MRI biomarkers in the management of cancer patients. They provide a clear, crisp explanation of MRI technology and key areas of ongoing and potential development. They include examples of two MRI methods, diffusion imaging and dynamic contrast-enhanced MRI, that recently have been incorporated into clinical trials of treatment response in solid tumors. Limitations and future research directions required for these techniques to gain greater acceptance and to have their maximum impact also are reviewed. Kristine Glunde and Zaver M. Bhujwalla at The Johns Hopkins University review the use of magnetic resonance spectroscopy (MRS) in cancer detection. They focus on noninvasive MRS and spectroscopic imaging (MRSI) and their roles in future personalized medicine in cancer. Diagnosis, the identification of the most effective treatment, monitoring treatment delivery, and response to treatment are some of the broad areas in which MRS techniques can be integrated to improve treatment outcomes. Alexei Bogdanov Jr and Mary L. Mazzanti at the University of Massachusetts discuss the molecular MRI contrast agents for the detection of cancer. Current efforts are directed toward developing a variety of MRI contrast agents with molecular specificities to the growing arSeminars in Oncology, Vol 38, No 1, February 2011, pp 1-2
mamentarium of diagnostic probes capable of changing local proton relaxation times as a consequence of specific contrast agent binding to cell surface receptors or extracellular matrix components. They review the most notable examples, illustrating major trends in the development of specific probes for high-resolution imaging in molecular oncology. Zhu and coworkers at Emory University address metabolic PET imaging in cancer detection and therapy response. Tumor imaging with positron emission tomography (PET) with fluorodeoxyglucose (FDG) FDGPET has been most widely used to improve the diagnosis and subsequent treatment of cancers. In addition, PET imaging using amino acid analogs has shown significant potential for tumor detection in organ sites with undesirable FDG-PET background (eg, methionine-PET and FACBC-PET). Kai Chen and Xiaoyuan Chen at the National Institutes of Health review the PET imaging beyond metabolic PET; over the last decade, numerous target-specific PET tracers have been developed and evaluated in preclinical and clinical studies. This review provides an overview of the current status and trends in the development of nonmetabolic PET probes in oncology and their application in the investigation of cancer biology. Brandon and colleagues at Emory University discuss the role of singlephoton emission computed tomography (SPECT) and SPECT/CT in oncologic imaging. SPECT has shown critical utility for cancer detection despite poor resolution of clinical scanners, eg, molecular breast imaging (MBI) technology, in sentinel node detection. As more disease-specific imaging agents become available, the role of SPECT/CT in the new paradigms of molecular imaging for personalized medicine will expand. They review established and emerging uses of SPECT/CT in a wide variety of oncologic diseases, as well as radiation exposure issues. The interdisciplinary team of Hadjipanayis et al (Emory University, University of Florida, Gainesville, and Dartmouth-Hitchcock Medical Center) discusses both current and future clinical applications for optical imaging, spanning the spectrum of cancer screening to intraoperative surgical guidance. Optical imaging is an inexpensive, fast, and sensitive imaging approach for noninvasively detecting human cancers in locations accessible to an optical imaging device. The use of optical imaging is now being applied in the clinic and 1
2
operating room for the localization and resection of malignant tumors in addition to screening for cancer. Additionally, Carl J. D’Orsi and Mary S. Newell at Emory University review the front line of screening for breast cancer including digital mammography, tomosynthesis, MRI, and ultrasound. In addition, they tackle the difficult topic of the risk-benefit assessment of screening mammography for women in the 40- to 49year age group. Lam and colleagues from the University of California at Davis describe improvements in CT technology and other factors that have contributed to an increase in the use of CT in the United States in recent years. The purpose of this review is to evaluate trends in CT use in cancer surveillance, especially among pediatric patients. Feleppa and coworkers at Riverside Research Institute, New York, review the use of quantitative ultrasound (QUS) in cancer imaging. Ultrasound is a relatively inexpensive, portable, and versatile imaging modality that has a broad range of clinical uses, especially in consideration of recent technology developments. This chapter discusses the attributes of QUSbased methods for imaging cancers and providing an improved means of detecting and assessing tumors. Kevin A. Smith and Hyun S. Kim at Emory University address advances in interventional radiology and image-
H. Shim and C.C. Meltzer
guided medicine for the cancer patient. Over the past three decades, technological advances have allowed transitioning from a role of diagnosis and surveillance to using imaging to guide minimally invasive therapies for an expanding range of oncology patients. Imageguided biopsy or minimally invasive therapies reduces the morbidity and cost associated with conventional surgical approaches. This chapter highlights the current trend of increasingly integrating image-guided interventions into oncologic care. In this issue Seminars, we review the current oncologic application of various imaging technologies and their benefits and shortfalls. We hope you will find this volume informative, and perhaps it may serve as a roadmap for additional applications of molecular, functional imaging to improve the diagnosis and subsequent treatment of cancers.
Hyunsuk Shim, PhD Carolyn C. Meltzer, MD Department of Radiology Emory University Atlanta, GA Guest Editors