Early dose response to yttrium-90 microsphere treatment of metastatic liver cancer by a patient-specific method using single photon emission computed tomography and positron emission tomography.
OBJECTIVE
To evaluate a patient-specific single photon emission computed tomography (SPECT)-based method of dose calculation for treatment planning of yttrium-90 ((90)Y) microsphere selective internal radiotherapy (SIRT).


METHODS
Fourteen consecutive (90)Y SIRTs for colorectal liver metastasis were retrospectively analyzed. Absorbed dose to tumor and normal liver tissue was calculated by partition methods with two different tumor/normal liver vascularity ratios: an average 3:1 and a patient-specific ratio derived from pretreatment technetium-99m macroaggregated albumin SPECT. Tumor response was quantitatively evaluated from fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography scans.


RESULTS
Positron emission tomography showed a significant decrease in total tumor standardized uptake value (average, 52%). There was a significant difference in the tumor absorbed dose between the average and specific methods (p = 0.009). Response vs. dose curves fit by linear and linear-quadratic modeling showed similar results. Linear fit r values increased for all tumor response parameters with the specific method (+0.20 for mean standardized uptake value).


CONCLUSIONS
Tumor dose calculated with the patient-specific method was more predictive of response in liver-directed (90)Y SIRT.
Department of Nuclear Medicine, William Beaumont Hospital, Royal Oak, MI; Department of Radiation Oncology, Wayne State University, Detroit, MI, USA.
Janice M
JM
Campbell
C Oliver
CO
Wong
Otto
O
Muzik
Brian
B
Marples
Michael
M
Joiner
Jay
J
Burmeister
D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000528:radiation effects; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000556:secondary; D008168:Lung / Q000000981:diagnostic imaging / Q000528:radiation effects; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011859:Radiography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*
D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D015021:Yttrium Radioisotopes