Open AccessPET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy
Author(s) -
Yoo Sung Song,
Jin Chul Paeng,
Hyo Cheol Kim,
Jin Wook Chung,
Gi Jeong Cheon,
June Key Chung,
Dong Hoon Lee,
Keon Wook Kang
Publication year - 2015
Publication title -
medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 148
eISSN - 1536-5964
pISSN - 0025-7974
DOI - 10.1097/md.0000000000000945
Subject(s) - medicine , nuclear medicine , dosimetry , microsphere , selective internal radiation therapy , radiation therapy , radiation treatment planning , absorbed dose , radiology , hepatocellular carcinoma , chemical engineering , engineering
Abstract 90 Y PET/CT can be acquired after 90 Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using 90 Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from 99m Tc-MAA scan and SPECT/CT. Twenty-three patients with liver malignancy were included in the study. 99m Tc-MAA was injected during planning angiography and whole body 99m Tc-MAA scan and liver SPECT/CT were acquired. After SIRT using 90 Y-resin microsphere, 90 Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from 99m Tc-MAA SPECT/CT and 90 Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by 99m Tc-MAA SPECT/CT and 90 Y-microsphere PET/CT results. Lung shunt fraction was overestimated on 99m Tc-MAA scan compared with 90 Y-microsphere PET/CT (0.060 ± 0.037 vs. 0.018 ± 0.026, P < 0.01). Tumor absorbed dose exhibited a close correlation between the results from 99m Tc-MAA SPECT/CT and 90 Y-microsphere PET/CT ( r = 0.64, P < 0.01), although the result from 99m Tc-MAA SPECT/CT was significantly lower than that from 90 Y-microsphere PET/CT (135.4 ± 64.2 Gy vs. 185.0 ± 87.8 Gy, P < 0.01). Absorbed dose to in-target normal liver was overestimated on 99m Tc-MAA SPECT/CT compared with PET/CT (62.6 ± 38.2 Gy vs. 45.2 ± 32.0 Gy, P = 0.02). Absorbed dose to out-target normal liver did not differ between 99m Tc-MAA SPECT/CT and 90 Y-microsphere PET/CT ( P = 0.49). Patients with tumor absorbed dose >200 Gy on 90 Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ≤200 Gy (286 ± 56 days vs. 92 ± 20 days, P = 0.046). Tumor absorbed dose calculated by 99m Tc-MAA SPECT/CT was not a significant predictor for PFS. Activity planning based on 99m Tc-MAA scan and SPECT/CT can be effectively used as a conservative method. Post-SIRT dosimetry based on 90 Y-microsphere PET/CT is an effective method to predict treatment efficacy.