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.
Division of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. nschecht@mdanderson.org
Naomi R
NR
Schechter
Richard E
RE
Wendt
David J
DJ
Yang
Ali
A
Azhdarinia
William D
WD
Erwin
Anne M
AM
Stachowiak
Lyle D
LD
Broemeling
E Edmund
EE
Kim
James D
JD
Cox
Donald A
DA
Podoloff
K Kian
KK
Ang
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