Biograph mCT PET•CT Evaluation of Chemotherapy Response in Lymphoma

Detection of metabolic change following chemotherapy or chemoradiation.

Jan Pruim, MD, PhD

Case study data provided by University Hospital Groningen, Groningen, The Netherlands

 |  2012-10-17

Case 1: Introduction
Fludeoxyglucose F 18* (18F FDG) PET and PET•CT are established as the mainstay of staging and restaging of lymphoma. 18F FDG PET is also very sensitive for detection of metabolic change in a tumor following chemotherapy or chemoradiation. The speed of response of a tumor to a particular therapy is of critical importance in response assessment and therapy continuation decisions.The more rapidly a tumor shrinks or faster the drop in tumor metabolic activity occurs, the more likely the response will be long standing. This is most obvious in therapy of lymphoma where residual masses are common following therapy completion in spite of significant and often complete remission of the disease as evident on 18F FDG PET•CT. Tumor masses in lymphoma are slow to decrease in size, often due to associated fibrosis and necrosis, although viable tumor burden may be grossly reduced. PET•CT following 1 or 2 cycles of chemotherapy is a reliable indicator of the metabolic response of the tumor to therapy and indicates the likelihood of a sustained remission.

*Siemens' PETNET Solutions is a manufacturer of fludeoxyglucose F 18 injection (18F FDG). Indication and important safety information as approved by the US Food and Drug Administration can be found at the bottom of the page for 18F FDG, adult dose 5-10 mCi, administered by intravenous injection.

History and Diagnosis

A 24-year-old male presented with a mediastinal mass detected in chest radiography along with night sweats, weight loss and cough (B symptoms). The biopsy of mediastinal mass revealed diffuse large-cell B cell lymphoma (DLBCL). Clinically, the diagnosis was "bulky" DLBCL stage IIb. The patient was referred for 18F FDG PET•CT for initial staging. Initial staging PET•CT demonstrated an extensive hypermetabolic mediastinal nodal mass along with solitary involved nodes in both axilla, as well as deposits in the inner margin on the anterior thoracic wall in the anterior pleural recess. Fused PET•CT images show significant infiltration of the chest wall. High resolution and lesion contrast on the Biograph™ mCT delineates small axillary nodal involvement. The patient was put on an R-CHOP14 chemotherapy regime (Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone) along with the monoclonal antibody rituximab given in cycles with 14-day intervals. Standard regime included 6 to 8 individual cycles. After 3 cycles, the patient underwent a follow-up 18F FDG PET•CT.

Case 2: Introduction
A second case demonstrates the difference between metabolic responses compared to change in tumor volume in lymphoma secondary to chemotherapy visualized on a Biograph mCT with high volumetric resolution and accurate SUV quantification.


A 14-year-old girl with a pelvic mass diagnosed as non-Hodgkin’s lymphoma by biopsy underwent initial staging with 18F FDG PET•CT in June 2011. The initial study showed a large hypermetabolic pelvic mass with 2 small peritoneal and 1 inguinal nodal lesions. The variegated appearance within the large  tumor mass is typical of matted lymph nodes. The patient was given chemotherapy with an R-CHOP14 regime, and the first follow-up 18F FDG PET•CT scan was performed in August  2011, after 2 cycles of chemotherapy. Chemotherapy was continued for 4 more cycles and the patient again underwent PET•CT in January 2012, after the completion of 6 cycles of chemotherapy. 

The statements by Siemens customers described herein are based on results that were achieved in the customer's unique setting. Since there is no "typical" hospital and many variables exist (e.g., hospital size, case mix, level of IT adoption) there can be no guarantee that other customers will achieve the same results.