PT  - JOURNAL ARTICLE
AU  - Kaste, Sue
AU  - Metzger, Monika
AU  - Sandlund, John
AU  - Snyder, Scott
AU  - Shulkin, Barry
TI  - Comparison of 11C-methionine and 18F-FDG PET-CT for staging and followup of pediatric lymphoma
DP  - 2016 May 01
TA  - Journal of Nuclear Medicine
PG  - 1778--1778
VI  - 57
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/57/supplement_2/1778.short
4100  - http://jnm.snmjournals.org/content/57/supplement_2/1778.full
SO  - J Nucl Med2016 May 01; 57
AB  - 1778Objectives 1. To determine the activity of (LAT1 - the large amino acid transporter) in sites of lymphoma using 11C-methionine (11C-MET) PET CT 2. To explore the uptake of 11C-MET in children and young adults with newly diagnosed Hodgkin lymphoma(HL) and non- Hodgkin lymphoma (NHL) for comparison with 18F-FDG PET-CT.Methods Patients with newly diagnosed HL (N=19) and NHL (N=2) were enrolled. After a minimum 4-hr fast, patients received 740 MBq/1.7 m2, maximum 740 MBq (20 mCi/1.7 m2, maximum, 20 mCi) 11C-methionine intravenously. PET-CT acquisition was performed 5 minutes post-injection from the vertex to thighs at 3 minutes per bed position in 3D. On a separate day, following a 4 hour or greater fast, patients received 5.5 MBq /kg, maximum 485 MBq (0.15 mCi/kg, maximum, 12 mCi) 18F-FDG with imaging initiated approximately 1 hour later. Reconstruction was performed using standard vendor supplied software. All studies were reviewed by consensus of two senior imaging specialists without reference to other imaging studies. Presence or absence of metabolic activity on baseline studies was compared among cervical, axillary,thoracic, abdominal and pelvic nodal groups, lung, liver, and spleen. SUVmax was determined by placing ROIs over regions of abnormal activity.Results Twenty evaluable patients (11 male, 15 white) median age 15.2 (range, 9.5 - 22.6) years comprise the study cohort with 18 paired 11C-METPET and 18F-FDGPET studies at diagnosis. At baseline, lymph groups in the neck and chest demonstrated concordant metabolic activity by both 18F-FDG and 11C-MET. Within the abdomen, FDG PET showed more areas of abnormal uptake in the liver and in iliac lymph nodes of affected patients. The median SUVmax for most sites of abnormal uptake was 1-2.5 fold higher for FDG. At follow-up, 14 of 15 study pairs were concordant.Conclusions 11C-MET uptake is elevated in most regions involved with lymphoma at diagnosis and follow-up. Uptake demonstrates over-activity of the large amino acid transporter and reduction during successful cytoreductive treatment. Utility in the abdomen and bone marrow is impaired by physiologic uptake in normal structures.