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Post-radioembolization yttrium-90 PET/CT - part 2: dose-response and tumor predictive dosimetry for resin microspheres.

Kao YH, Steinberg JD, Tay YS, Lim GK, Yan J, Townsend DW, Budgeon CA, Boucek JA, Francis RJ, Cheo TS, Burgmans MC, Irani FG, Lo RH, Tay KH, Tan BS, Chow PKh, Satchithanantham S, Tan AE, Ng DC, Goh AS - EJNMMI Res (2013)

Bottom Line: There was complete response in a cholangiocarcinoma at D70 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D70 53 Gy.In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis.In one patient, a bilateral kidney mean dose of 9 Gy (V20 8%) did not cause clinically relevant nephrotoxicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Medicine and PET, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. yung.h.kao@gmail.com.

ABSTRACT

Background: Coincidence imaging of low-abundance yttrium-90 (90Y) internal pair production by positron emission tomography with integrated computed tomography (PET/CT) achieves high-resolution imaging of post-radioembolization microsphere biodistribution. Part 2 analyzes tumor and non-target tissue dose-response by 90Y PET quantification and evaluates the accuracy of tumor 99mTc macroaggregated albumin (MAA) single-photon emission computed tomography with integrated CT (SPECT/CT) predictive dosimetry.

Methods: Retrospective dose quantification of 90Y resin microspheres was performed on the same 23-patient data set in part 1. Phantom studies were performed to assure quantitative accuracy of our time-of-flight lutetium-yttrium-oxyorthosilicate system. Dose-responses were analyzed using 90Y dose-volume histograms (DVHs) by PET voxel dosimetry or mean absorbed doses by Medical Internal Radiation Dose macrodosimetry, correlated to follow-up imaging or clinical findings. Intended tumor mean doses by predictive dosimetry were compared to doses by 90Y PET.

Results: Phantom studies demonstrated near-perfect detector linearity and high tumor quantitative accuracy. For hepatocellular carcinomas, complete responses were generally achieved at D70 > 100 Gy (D70, minimum dose to 70% tumor volume), whereas incomplete responses were generally at D70 < 100 Gy; smaller tumors (<80 cm3) achieved D70 > 100 Gy more easily than larger tumors. There was complete response in a cholangiocarcinoma at D70 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D70 53 Gy. In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis. In one patient, a bilateral kidney mean dose of 9 Gy (V20 8%) did not cause clinically relevant nephrotoxicity. Under near-ideal dosimetric conditions, there was excellent correlation between intended tumor mean doses by predictive dosimetry and those by 90Y PET, with a low median relative error of +3.8% (95% confidence interval, -1.2% to +13.2%).

Conclusions: Tumor and non-target tissue absorbed dose quantification by 90Y PET is accurate and yields radiobiologically meaningful dose-response information to guide adjuvant or mitigative action. Tumor 99mTc MAA SPECT/CT predictive dosimetry is feasible. 90Y DVHs may guide future techniques in predictive dosimetry.

No MeSH data available.


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Patient 9. 90Y radioembolization of an organ other than the liver. KIT-negative GIST with bulky metastasis to the right adrenal gland, refractory to tyrosine kinase inhibitors. Angiography was previously shown in part 1 [1]. (a) Catheter-directed CT angiogram of the right inferior adrenal artery delineates the targeted right adrenal tumor measuring 10.1 × 6.3 cm. (b) Post-radioembolization 90Y PET/CT depicts microsphere biodistribution in high resolution, with concordant activity within targeted regions of contrast-enhancing tumor. Low-grade activity seen in the adjacent right liver lobe is due to 90Y radioembolization of a segment IV metastasis. (c) Isodose map by voxel dosimetry of the corresponding trans-axial slice of the right adrenal tumor provides a visual representation of dose heterogeneity within the tumor and adjacent right liver lobe and displays the full dose range from 0 to >1,000 Gy. (d) Follow-up contrast-enhanced CT of the abdomen at 9.5 months shows a moderate size reduction to 7.6 × 4.6 cm, representing a partial response.
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Figure 3: Patient 9. 90Y radioembolization of an organ other than the liver. KIT-negative GIST with bulky metastasis to the right adrenal gland, refractory to tyrosine kinase inhibitors. Angiography was previously shown in part 1 [1]. (a) Catheter-directed CT angiogram of the right inferior adrenal artery delineates the targeted right adrenal tumor measuring 10.1 × 6.3 cm. (b) Post-radioembolization 90Y PET/CT depicts microsphere biodistribution in high resolution, with concordant activity within targeted regions of contrast-enhancing tumor. Low-grade activity seen in the adjacent right liver lobe is due to 90Y radioembolization of a segment IV metastasis. (c) Isodose map by voxel dosimetry of the corresponding trans-axial slice of the right adrenal tumor provides a visual representation of dose heterogeneity within the tumor and adjacent right liver lobe and displays the full dose range from 0 to >1,000 Gy. (d) Follow-up contrast-enhanced CT of the abdomen at 9.5 months shows a moderate size reduction to 7.6 × 4.6 cm, representing a partial response.

Mentions: Twenty-three post-radioembolization 90Y PET/CT scans were eligible for dose-response analysis, as was reported in part 1 [1]. As per our institutional protocol, the catheter tip for 90Y resin microsphere injection was placed in exactly the same position as for 99mTc MAA injection in all cases, as visually assessed by the procedural interventional radiologist during 90Y radioembolization. Only eight patients fulfilled all tumor selection criteria: patients 1, 2, 8, 9, 17, 19, 21, and 23. The median tumor-to-normal liver (T/N) ratio estimated by 99mTc MAA SPECT/CT was 5.0 (mean 8.0, range 1.8 to 21.9). Tumor 90Y DVH dose-response results involving hepatocellular carcinomas (HCC), cholangiocarcinoma, and adrenal metastatic gastrointestinal stromal tumor (GIST; Figures 3 and 4) are presented in Table 1. Across HCCs of various lesion sizes, cross-analysis of seven 90Y DVHs suggest that complete responses were generally achieved at D70 > 100 Gy, whereas tumors with incomplete responses generally have D70 < 100 Gy (Figure 5). Smaller HCCs, such as those <80 cm3, achieved D70 > 100 Gy more easily than larger tumors. dose-response results of portal vein tumor thrombosis by 90Y MIRD macrodosimetry (Figure 6) are presented in Table 2.


Post-radioembolization yttrium-90 PET/CT - part 2: dose-response and tumor predictive dosimetry for resin microspheres.

Kao YH, Steinberg JD, Tay YS, Lim GK, Yan J, Townsend DW, Budgeon CA, Boucek JA, Francis RJ, Cheo TS, Burgmans MC, Irani FG, Lo RH, Tay KH, Tan BS, Chow PKh, Satchithanantham S, Tan AE, Ng DC, Goh AS - EJNMMI Res (2013)

Patient 9. 90Y radioembolization of an organ other than the liver. KIT-negative GIST with bulky metastasis to the right adrenal gland, refractory to tyrosine kinase inhibitors. Angiography was previously shown in part 1 [1]. (a) Catheter-directed CT angiogram of the right inferior adrenal artery delineates the targeted right adrenal tumor measuring 10.1 × 6.3 cm. (b) Post-radioembolization 90Y PET/CT depicts microsphere biodistribution in high resolution, with concordant activity within targeted regions of contrast-enhancing tumor. Low-grade activity seen in the adjacent right liver lobe is due to 90Y radioembolization of a segment IV metastasis. (c) Isodose map by voxel dosimetry of the corresponding trans-axial slice of the right adrenal tumor provides a visual representation of dose heterogeneity within the tumor and adjacent right liver lobe and displays the full dose range from 0 to >1,000 Gy. (d) Follow-up contrast-enhanced CT of the abdomen at 9.5 months shows a moderate size reduction to 7.6 × 4.6 cm, representing a partial response.
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Related In: Results  -  Collection

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Figure 3: Patient 9. 90Y radioembolization of an organ other than the liver. KIT-negative GIST with bulky metastasis to the right adrenal gland, refractory to tyrosine kinase inhibitors. Angiography was previously shown in part 1 [1]. (a) Catheter-directed CT angiogram of the right inferior adrenal artery delineates the targeted right adrenal tumor measuring 10.1 × 6.3 cm. (b) Post-radioembolization 90Y PET/CT depicts microsphere biodistribution in high resolution, with concordant activity within targeted regions of contrast-enhancing tumor. Low-grade activity seen in the adjacent right liver lobe is due to 90Y radioembolization of a segment IV metastasis. (c) Isodose map by voxel dosimetry of the corresponding trans-axial slice of the right adrenal tumor provides a visual representation of dose heterogeneity within the tumor and adjacent right liver lobe and displays the full dose range from 0 to >1,000 Gy. (d) Follow-up contrast-enhanced CT of the abdomen at 9.5 months shows a moderate size reduction to 7.6 × 4.6 cm, representing a partial response.
Mentions: Twenty-three post-radioembolization 90Y PET/CT scans were eligible for dose-response analysis, as was reported in part 1 [1]. As per our institutional protocol, the catheter tip for 90Y resin microsphere injection was placed in exactly the same position as for 99mTc MAA injection in all cases, as visually assessed by the procedural interventional radiologist during 90Y radioembolization. Only eight patients fulfilled all tumor selection criteria: patients 1, 2, 8, 9, 17, 19, 21, and 23. The median tumor-to-normal liver (T/N) ratio estimated by 99mTc MAA SPECT/CT was 5.0 (mean 8.0, range 1.8 to 21.9). Tumor 90Y DVH dose-response results involving hepatocellular carcinomas (HCC), cholangiocarcinoma, and adrenal metastatic gastrointestinal stromal tumor (GIST; Figures 3 and 4) are presented in Table 1. Across HCCs of various lesion sizes, cross-analysis of seven 90Y DVHs suggest that complete responses were generally achieved at D70 > 100 Gy, whereas tumors with incomplete responses generally have D70 < 100 Gy (Figure 5). Smaller HCCs, such as those <80 cm3, achieved D70 > 100 Gy more easily than larger tumors. dose-response results of portal vein tumor thrombosis by 90Y MIRD macrodosimetry (Figure 6) are presented in Table 2.

Bottom Line: There was complete response in a cholangiocarcinoma at D70 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D70 53 Gy.In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis.In one patient, a bilateral kidney mean dose of 9 Gy (V20 8%) did not cause clinically relevant nephrotoxicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Medicine and PET, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. yung.h.kao@gmail.com.

ABSTRACT

Background: Coincidence imaging of low-abundance yttrium-90 (90Y) internal pair production by positron emission tomography with integrated computed tomography (PET/CT) achieves high-resolution imaging of post-radioembolization microsphere biodistribution. Part 2 analyzes tumor and non-target tissue dose-response by 90Y PET quantification and evaluates the accuracy of tumor 99mTc macroaggregated albumin (MAA) single-photon emission computed tomography with integrated CT (SPECT/CT) predictive dosimetry.

Methods: Retrospective dose quantification of 90Y resin microspheres was performed on the same 23-patient data set in part 1. Phantom studies were performed to assure quantitative accuracy of our time-of-flight lutetium-yttrium-oxyorthosilicate system. Dose-responses were analyzed using 90Y dose-volume histograms (DVHs) by PET voxel dosimetry or mean absorbed doses by Medical Internal Radiation Dose macrodosimetry, correlated to follow-up imaging or clinical findings. Intended tumor mean doses by predictive dosimetry were compared to doses by 90Y PET.

Results: Phantom studies demonstrated near-perfect detector linearity and high tumor quantitative accuracy. For hepatocellular carcinomas, complete responses were generally achieved at D70 > 100 Gy (D70, minimum dose to 70% tumor volume), whereas incomplete responses were generally at D70 < 100 Gy; smaller tumors (<80 cm3) achieved D70 > 100 Gy more easily than larger tumors. There was complete response in a cholangiocarcinoma at D70 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D70 53 Gy. In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis. In one patient, a bilateral kidney mean dose of 9 Gy (V20 8%) did not cause clinically relevant nephrotoxicity. Under near-ideal dosimetric conditions, there was excellent correlation between intended tumor mean doses by predictive dosimetry and those by 90Y PET, with a low median relative error of +3.8% (95% confidence interval, -1.2% to +13.2%).

Conclusions: Tumor and non-target tissue absorbed dose quantification by 90Y PET is accurate and yields radiobiologically meaningful dose-response information to guide adjuvant or mitigative action. Tumor 99mTc MAA SPECT/CT predictive dosimetry is feasible. 90Y DVHs may guide future techniques in predictive dosimetry.

No MeSH data available.


Related in: MedlinePlus