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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.


Related in: MedlinePlus

Example of a 90Y PET/CT phantom scan with maximum intensity projection image. (a) Trans-axial, (b) coronal, and (c) sagittal planes. This scan shows our lowest tested vial sediment activity of 3.5 MBq (≈3 MBq/ml). The upper PET visual display threshold of this scan was adjusted to 114% (2,000 kBq/ml) to minimize visual interference from background noise [1]. (d) Maximum intensity projection image of the same phantom scan (arrow indicates vial sediment) with the upper PET visual display threshold adjusted to 1% (20 kBq/ml) to reveal the underlying background noise as an example to readers [1].
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Figure 1: Example of a 90Y PET/CT phantom scan with maximum intensity projection image. (a) Trans-axial, (b) coronal, and (c) sagittal planes. This scan shows our lowest tested vial sediment activity of 3.5 MBq (≈3 MBq/ml). The upper PET visual display threshold of this scan was adjusted to 114% (2,000 kBq/ml) to minimize visual interference from background noise [1]. (d) Maximum intensity projection image of the same phantom scan (arrow indicates vial sediment) with the upper PET visual display threshold adjusted to 1% (20 kBq/ml) to reveal the underlying background noise as an example to readers [1].

Mentions: Vials of microspheres were obtained by convenience sampling, either before or after extraction of the desired treatment activity. Phantom scans of high activities (>3.0 GBq) were performed on fresh vials on the day it was received from the manufacturer, while scans of very low activities (<0.1 GBq) were performed after a period of decay of residual vial activities. The vials were placed within a perspex body phantom and scanned in one bed position over 15 min (Figure 1). All scan parameters were identical to our clinical scan protocol described in part 1 [1].


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)

Example of a 90Y PET/CT phantom scan with maximum intensity projection image. (a) Trans-axial, (b) coronal, and (c) sagittal planes. This scan shows our lowest tested vial sediment activity of 3.5 MBq (≈3 MBq/ml). The upper PET visual display threshold of this scan was adjusted to 114% (2,000 kBq/ml) to minimize visual interference from background noise [1]. (d) Maximum intensity projection image of the same phantom scan (arrow indicates vial sediment) with the upper PET visual display threshold adjusted to 1% (20 kBq/ml) to reveal the underlying background noise as an example to readers [1].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733999&req=5

Figure 1: Example of a 90Y PET/CT phantom scan with maximum intensity projection image. (a) Trans-axial, (b) coronal, and (c) sagittal planes. This scan shows our lowest tested vial sediment activity of 3.5 MBq (≈3 MBq/ml). The upper PET visual display threshold of this scan was adjusted to 114% (2,000 kBq/ml) to minimize visual interference from background noise [1]. (d) Maximum intensity projection image of the same phantom scan (arrow indicates vial sediment) with the upper PET visual display threshold adjusted to 1% (20 kBq/ml) to reveal the underlying background noise as an example to readers [1].
Mentions: Vials of microspheres were obtained by convenience sampling, either before or after extraction of the desired treatment activity. Phantom scans of high activities (>3.0 GBq) were performed on fresh vials on the day it was received from the manufacturer, while scans of very low activities (<0.1 GBq) were performed after a period of decay of residual vial activities. The vials were placed within a perspex body phantom and scanned in one bed position over 15 min (Figure 1). All scan parameters were identical to our clinical scan protocol described in part 1 [1].

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