RADAR Commentary: Evolution and Current Status of Dosimetry in Nuclear Medicine

Stabin, Michael G.; Sharkey, Robert M.; Siegel, Jeffry A.

doi:10.2967/jnumed.111.088666

Cited by 21 publications

(12 citation statements)

References 26 publications

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“…Precise predictive dosimetry has the potential to yield many benefits for cancer therapy, and the need for further research into internal dosimetry has recently been emphasized (31). To our knowledge, the artery-specific SPECT/ CT partition model is the first to integrate catheter-directed CTHA, 99m Tc-MAA SPECT/CT, and partition modeling (MIRD) into a unified, accurate, and practical form of image-guided personalized predictive dosimetry for 90 Y radioembolization.…”

Section: Discussionmentioning

confidence: 99%

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization

Kao¹,

Tan²,

Burgmans³

et al. 2012

J Nucl Med

151

133

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Compliance with radiobiologic principles of radionuclide internal dosimetry is fundamental to the success of 90 Y radioembolization. The artery-specific SPECT/CT partition model is an image-guided personalized predictive dosimetric technique developed by our institution, integrating catheter-directed CT hepatic angiography (CTHA), 99m Tc-macroaggregated albumin SPECT/CT, and partition modeling for unified dosimetry. Catheter-directed CTHA accurately delineates planning target volumes. SPECT/CT tomographically evaluates 99m Tc-macroaggregated albumin hepatic biodistribution. The partition model is validated for 90 Y resin microspheres based on MIRD macrodosimetry. Methods: This was a retrospective analysis of ourearly clinical outcomes for inoperable hepatocellular carcinoma. Mapping hepatic angiography was performed according to standard technique with the addition of catheter-directed CTHA. 99m Tc-MAA planar scintigraphy was used for liver-tolung shunt estimation, and SPECT/CT was used for liver dosimetry. Artery-specific SPECT/CT partition modeling was planned by experienced nuclear medicine physicians. Results: From January to May 2011, 20 arterial territories were treated in 10 hepatocellular carcinoma patients. Median follow-up was 21 wk (95% confidence interval [CI], 12-50 wk). When analyzed strictly as brachytherapy, 90 Y radioembolization planned by predictive dosimetry achieved index tumor regression in 8 of 8 patients, with a median size decrease of 58% (95% CI, 40%-72%). Tumor thrombosis regressed or remained stable in 3 of 4 patients with baseline involvement. The best a-fetoprotein reduction ranged from 32% to 95%. Clinical success was achieved in 7 of 8 patients, including 2 by sublesional dosimetry, in 1 of whom there was radioembolization lobectomy intent. Median predicted mean radiation absorbed doses were 106 Gy (95% CI, 105-146 Gy) to tumor, 27 Gy (95% CI, 22-33 Gy) to nontumorous liver, and 2 Gy (95% CI, 1.3-7.3 Gy) to lungs. Across all patients, tumor, nontumorous liver, and lungs received predicted $91 Gy, #51 Gy, and #16 Gy, respectively, via at least 1 target arterial territory. No patients developed significant toxicities within 3 mo after radioembolization. The median time to best imaging response was 76 d (95% CI, 55-114 d). Median time to progression and overall survival were not reached. SPECT/CT-derived mean tumor-to-normal liver ratios varied widely across all planning target volumes (median, 5.4; 95% CI, 4.1-6.7), even within the same patient. Conclusion: Imageguided personalized predictive dosimetry by artery-specific SPECT/CT partition modeling achieves high clinical success rates for safe and effective 90 Y radioembolization. Asaformofart erial territory-specific point-source brachytherapy, 90 Y radioembolization is always effective when delivered at the right location, in the right dose, and with the right intent. 90 Y radioembolization failure is invariably due to one or a combination of these 3 factors being incorrectly addressed. Responsibility for this triad of factors is ...

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Section: Discussionmentioning

confidence: 99%

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization

Kao¹,

Tan²,

Burgmans³

et al. 2012

J Nucl Med

151

133

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“…In this work we evaluated the in vivo biodistribution of [ 18 F]Nifene in the mouse organs using whole-body PET and CT imaging. Residence times were computed for several mouse organs and absorbed doses were then derived using the RAdiation Dose Assessment Resource (RADAR) models for dose assessment developed at Vanderbilt University [17] [18]. The mouse residence times were extrapolated to humans based on simple assumptions on difference between the species.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of [18F]Nifene biodistribution and dosimetry based on whole-body PET imaging of mice

Constantinescu

Garcia

Mirbolooki

et al. 2013

Nuclear Medicine and Biology

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Introduction [18F]Nifene is a novel radiotracer specific to the nicotinic acetylcholine α4β2 receptor class. In preparation for using this tracer in humans we have performed whole-body PET studies in mice to evaluate the in vivo biodistribution and dosimetry of [18F]Nifene. Methods Seven BALB/c mice (3 males, 4 females) received IV tail injections of [18F]Nifene and scanned for 2 hours in an Inveon dedicated PET scanner. Each animal also received a high resolution CT scan using an Inveon CT. The CT images were used to draw volume of interest (VOI) on the following organs: brain, large intestine, small intestine, stomach, heart, kidneys, liver, lungs, pancreas, bone, spleen, testes, thymus, uterus and urinary bladder. All organ time activity curves had the decay correction reversed and were normalized to the injected activity. The area under the normalized curves was then used to compute the residence times in each organ. The absorbed doses in mouse organs were computed using the RAdiation Dose Assessment Resource (RADAR) animal models for dose assessment. The residence times in mouse organs were converted to human values using scale factors based on differences between organ and body weights. OLINDA 1.1 software was used to compute the absorbed human doses in multiple organs for both female and male phantoms. Results The highest mouse residence times were found in urinary bladder, liver, bone, small intestine and kidneys. The largest doses in mice were found in urinary bladder and kidneys for both females and males. The elimination of radiotracer was primarily via kidney and urinary bladder with the urinary bladder being the limiting organ. The projected human effective doses were 1.51E-02 mSv/MBq for the adult male phantom and 1.65E-02 mSv/MBq for the adult female model phantom. Conclusion This study indicates that the whole-body mouse imaging can be used as a preclinical tool for initial estimation of the absorbed doses of [18F]Nifene in humans.

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“…Residence times were computed for several mouse organs, and absorbed doses were then derived using the RAdiation Dose Assessment Resource (RADAR) models for dose assessment developed at Vanderbilt University [12, 13]. The mouse residence times were extrapolated to humans based on simple assumptions on difference between the species.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of [18F]Mefway Biodistribution and Dosimetry Based on Whole-Body PET Imaging of Mice

et al. 2012

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Purpose [18F]Mefway is a novel radiotracer specific to the serotonin 5-HT1A receptor class. In preparation for using this tracer in humans, we have performed whole-body PET studies in mice to evaluate the biodistribution and dosimetry of [18F]Mefway. Methods Six mice (three females and three males) received IV injections of [18F]Mefway and were scanned for 2 h in an Inveon-dedicated PET scanner. Each animal also received a high-resolution CT scan using an Inveon CT. The CT images were used to draw volume of interest on the following organs: the brain, large intestine, stomach, heart, kidneys, liver, lungs, pancreas, bone, spleen, testes, thymus, gallbladder, uterus, and urinary bladder. All organ time-activity curves without decay correction were normalized to the injected activity. The area under the normalized curves was then used to compute the residence times in each organ. Data were analyzed using PMOD and Matlab software. The absorbed doses in mouse organs were computed using the RAdiation Dose Assessment Resource animal models for dose assessment. The residence times in mouse organs were converted to human values using scale factors based on differences between organ and body weights. OLINDA/EXM 1.1 software was used to compute the absorbed human doses in multiple organs for both female and male phantoms. Results The highest mouse residence times were found in the liver, urinary bladder, and kidneys. The largest doses in mice were found in the urinary bladder (critical organ), kidney, and liver for both females and males, indicating primary elimination via urinary system. The projected human effective doses were 1.21E–02 mSv/MBq for the adult female model and 1.13E–02 mSv/MBq for the adult male model. The estimated human biodistribution of [18F]Mefway was similar to that of [11C]WAY 100,635, a 5-HT1A tracer for which dosimetry has been evaluated in humans. Conclusions The elimination of radiotracer was primarily via the kidney and urinary bladder with the urinary bladder being the critical organ. Whole-body mouse imaging can be used as a preclinical tool to provide initial estimates of the absorbed doses of [18F]Mefway in humans.

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RADAR Commentary: Evolution and Current Status of Dosimetry in Nuclear Medicine

Cited by 21 publications

References 26 publications

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization

Evaluation of [18F]Nifene biodistribution and dosimetry based on whole-body PET imaging of mice

Evaluation of [18F]Mefway Biodistribution and Dosimetry Based on Whole-Body PET Imaging of Mice

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RADAR Commentary: Evolution and Current Status of Dosimetry in Nuclear Medicine

Cited by 21 publications

References 26 publications

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective 90Y Radioembolization

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective 90Y Radioembolization

Evaluation of [18F]Nifene biodistribution and dosimetry based on whole-body PET imaging of mice

Evaluation of [18F]Mefway Biodistribution and Dosimetry Based on Whole-Body PET Imaging of Mice

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Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization

Image-Guided Personalized Predictive Dosimetry by Artery-Specific SPECT/CT Partition Modeling for Safe and Effective ⁹⁰Y Radioembolization