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Dejanovic D, Specht L, Czyzewska D, Kiil Berthelsen A, Loft A. Response Evaluation Following Radiation Therapy With 18F-FDG PET/CT: Common Variants of Radiation-Induced Changes and Potential Pitfalls. Semin Nucl Med 2022; 52:681-706. [PMID: 35835618 DOI: 10.1053/j.semnuclmed.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/11/2022]
Abstract
Radiation therapy (RT) is one of the cornerstones in cancer treatment and approximately half of all patients will receive some form of RT during the course of their cancer management. Response evaluation after RT and follow-up imaging with 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can be complicated by RT-induced acute, chronic or consequential effects. There is a general consensus that 18F-FDG PET/CT for response evaluation should be delayed for 12 weeks after completing RT to minimize the risk of false-positive findings. Radiation-induced late side effects in normal tissue can take years to develop and eventually cause symptoms that on imaging can potentially mimic recurrent disease. Imaging findings in radiation induced injuries depend on the normal tissue included in the irradiated volume and the radiation therapy regime including the total dose delivered, dose per fraction and treatment schedule. The intent for radiation therapy should be taken in consideration when evaluating the response on imaging, that is palliative vs curative or neoadjuvant vs adjuvant RT. Imaging findings can further be distorted by altered anatomy and sequelae following surgery within the radiation field. An awareness of common PET/CT-induced changes/injuries is essential when interpreting 18F-FDG PET/CT as well as obtaining a complete medical history, as patients are occasionally scanned for an unrelated cause to previously RT treated malignancy. In addition, secondary malignancies due to carcinogenic effects of radiation exposure in long-term cancer survivors should not be overlooked. 18F-FDG PET/CT can be very useful in response evaluation and follow-up in patients treated with RT, however, variants and pitfalls are common and it is important to remember that radiation-induced injury is often a diagnosis of exclusion.
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Affiliation(s)
- Danijela Dejanovic
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
| | - Lena Specht
- Department of Oncology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark
| | - Dorota Czyzewska
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Anne Kiil Berthelsen
- Department of Oncology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark
| | - Annika Loft
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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Lang JA, Bhalla S, Ganeshan D, Felder GJ, Itani M. Side Effects of Oncologic Treatment in the Chest: Manifestations at FDG PET/CT. Radiographics 2021; 41:2071-2089. [PMID: 34723703 DOI: 10.1148/rg.2021210130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fluorodeoxyglucose (FDG) PET/CT is a vital imaging technique used for staging, assessing treatment response, and restaging following completion of therapy in patients who are undergoing or have completed oncologic treatment. A variety of adverse effects from chemotherapy, targeted therapy, immunotherapy, and radiation therapy are commonly encountered in oncologic patients. It is important to be aware of the manifestations of these adverse effects seen on FDG PET/CT images to avoid misinterpreting these findings as disease progression. Furthermore, early identification of these complications is important, as it may significantly affect patient management and even lead to a change in treatment strategy. The authors focus on the FDG PET/CT manifestations of a broad spectrum of oncologic therapy-related adverse effects in the thorax, as well as some treatment-related changes that may potentially mimic malignancy. Online supplemental material is available for this article. ©RSNA, 2021.
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Affiliation(s)
- Jordan A Lang
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box #8131, St Louis, MO 63110 (J.A.L., S.B., M.I.); Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Tex (D.G.); and Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.)
| | - Sanjeev Bhalla
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box #8131, St Louis, MO 63110 (J.A.L., S.B., M.I.); Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Tex (D.G.); and Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.)
| | - Dhakshinamoorthy Ganeshan
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box #8131, St Louis, MO 63110 (J.A.L., S.B., M.I.); Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Tex (D.G.); and Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.)
| | - Gabriel J Felder
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box #8131, St Louis, MO 63110 (J.A.L., S.B., M.I.); Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Tex (D.G.); and Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.)
| | - Malak Itani
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box #8131, St Louis, MO 63110 (J.A.L., S.B., M.I.); Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Tex (D.G.); and Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.)
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Cardiac ¹⁸F-fluorodeoxyglucose uptake on positron emission tomography after thoracic stereotactic body radiation therapy. Radiother Oncol 2013; 109:82-8. [PMID: 24016676 DOI: 10.1016/j.radonc.2013.07.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/16/2013] [Accepted: 07/23/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies have shown that increased cardiac uptake of (18)F-fluorodeoxyglucose (FDG) on positron emission tomography (PET) may be an indicator of myocardial injury after radiotherapy. We reviewed patients treated with thoracic stereotactic body radiation therapy (SBRT) and established correlations between SBRT dose and observed changes in cardiac FDG-PET uptake. MATERIAL AND METHODS Retrospective analysis identified 39 patients that were treated with SBRT for lung tumors close to the heart. Patients were grouped according to whether or not they had changes in cardiac FDG-PET uptake within the planned SBRT field. RESULTS At a median follow-up interval of 39 months (range, 6-81 months), nine patients (23%) showed increased cardiac FDG uptake associated with the heart V₂₀. Of the 19 patients who received 20 Gy to ≥5 cm(3) of the heart, nine (47%) developed increased FDG uptake (vs. 0% for the 20 patients who received 20 Gy to <5 cm(3)) (P=0.0004), all within the 20-Gy isodose line. Patients with hypercholesterolemia prior to SBRT were also more likely to show increased cardiac FDG uptake (P=0.0190). CONCLUSION Increased FDG uptake in the heart after SBRT was observed when the 20 Gy isodose line exceeded 5 cm(3) of the heart.
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