Radiation dosimetry of 99mTc-labeled C225 in patients with squamous cell carcinoma of the head and neck.
This study assessed the radiation dosimetry of 99mTc-labeled ethylene dicysteine (EC) C225 (EC-C225), a promising radioligand for functional tumor imaging.


METHODS
Whole-body scanning was performed on 6 patients with head and neck squamous cell carcinoma up to 24 h after administration of 99mTc-EC-C225. Alternate patients who had been randomized to receive C225 in a phase III trial received 99mTc-EC-C225 before their 20-mg test dose or after their 400 mg/m2 loading dose of unlabeled C225 (patients 1/3/5 and 2/4/6, respectively). Radiation dosimetry was assessed using the MIRD method.


RESULTS
The critical organ was the kidney, with an average radiation-absorbed dose for all 6 patients of 0.0274 mGy/MBq. The average total-body absorbed dose was 0.0022 mGy/MBq (0.243 cGy/1,110 MBq).


CONCLUSIONS
The new radiopharmaceutical 99mTc-EC-C225 appears to have reasonable dosimetric properties for a diagnostic nuclear medicine agent. Correlation of the imaging results with clinical findings is the next step.
Schechter
Naomi R
NR
Division of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. nschecht@mdanderson.org
Wendt
Richard E
RE
Yang
David J
DJ
Azhdarinia
Ali
A
Erwin
William D
WD
Stachowiak
Anne M
AM
Broemeling
Lyle D
LD
Kim
E Edmund
EE
Cox
James D
JD
Podoloff
Donald A
DA
Ang
K Kian
KK
D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001822:Body Burden; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000532:radiotherapy; D000068818:Cetuximab; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000532:radiotherapy; D006801:Humans; D009928:Organ Specificity; D049268:Positron-Emission Tomography / Q000379:methods; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012680:Sensitivity and Specificity; D013667:Technetium / Q000493:pharmacokinetics / Q000627:therapeutic use; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D019275:Radiopharmaceuticals; D013667:Technetium; D000068818:Cetuximab