Estimate of the 225Ac Radioactive Isotope Distribution by Means of DOI Compton Imaging in Targeted Alpha Radiotherapy: A Monte Carlo Simulation

Yoon, Changyeon; Jo, Seongmin; Cho, Yongho; Kim, Nakjeom; Lee, Taewoong

doi:10.3938/jkps.76.954

Cited by 4 publications

(7 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, we present images of mice with injected activities of 20 kBq. Other works have already proposed a Compton camera for the preclinical evaluation of the daughter 221 Bi; 24,25 however, none have demonstrated the feasibility of this modality via experimentation. The most recent study by Caravaca et al 25 simulates the response Previous works have proposed and employed coded apertures for small-animal imaging, 26 but as far as we know, this work is the first to recommend a coded aperture for imaging 221 Fr via its 218-keV emission in small animals.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals

Frame,

Bobba,

Gunter

et al. 2023

Medical Physics

View full text Add to dashboard Cite

BackgroundTargeted alpha‐particle therapy (TAT) has great promise as a cancer treatment. Arguably the most promising TAT radionuclide that has been proposed is 225Ac. The development of 225Ac‐based radiopharmaceuticals has been hampered due to the lack of effective means to study the daughter redistribution of these agents in small animals at the preclinical stage.PurposeThe ability to directly image the daughters, namely 221Fr and 213Bi, via their gamma‐ray emissions would be a boon for preclinical studies. That said, conventional medical imaging modalities, including single photon emission computed tomography (SPECT) based on nonmultiplexed collimation, cannot be employed due to sensitivity limitations.MethodsAs an alternative, we propose the use of both coded aperture and Compton imaging with the former modality suited to the 218‐keV gamma‐ray emission of 221Fr and the latter suited to the 440‐keV gamma‐ray emission of 213Bi.ResultsThis work includes coded aperture images of 221Fr and Compton images of 213Bi in tumor‐bearing mice injected with 225Ac‐based radiopharmaceuticals.ConclusionsThese results are the first demonstration of visualizing and quantifying the 225Ac daughters in small animals through the application of coded aperture and Compton imaging.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Other works have already proposed a Compton camera for the preclinical evaluation of the daughter 221 Bi; 24,25 however, none have demonstrated the feasibility of this modality via experimentation. The most recent study by Caravaca et al 25 .…”

Section: Discussionmentioning

confidence: 99%

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals

Frame,

Bobba,

Gunter

et al. 2023

Medical Physics

View full text Add to dashboard Cite

show abstract

“…A new concept of high-sensitivity multipinhole collimator dedicated to TAT imaging [23] could meet the requirements, although in vivo imaging with submicrocurie doses is still to be demonstrated. Yoon et al [36] proposed a Compton camera using GAGG to image 221 Fr and 213 Bi from 225 Ac. Their tested activities (∼Mbq/ml) are three orders of magnitude higher than our targeted activities (∼kbq/ml).…”

Section: B Comparison With Other Studiesmentioning

confidence: 99%

“…The role of CZT as a high-Z scatterer is also critical, since it provides a relatively large Compton interaction rate and, at the same time, allowing for those photons to escape and to reach the absorber. Compared to GAGG [36], CZT outperforms its sensitivity, partially due to this reason. The superb energy resolution of CZT (better than most traditional scintillators [58]) is also required to obtain a high spatial resolution for Compton imaging.…”

Section: Detector Modeling Considerationsmentioning

confidence: 99%

“…We explore a cadmium-zinctelluride (CZT) gamma camera that uses both modalities in order to enable a high sensitivity system, able to reconstruct in vivo images of 221 Fr and 213 Bi from 225 Ac radiopharmaceuticals. In [36], a GAGG Compton camera is proposed to image 225 Ac, showing promising results with simulated phantoms, although with doses that are much higher than the safe dose.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Compton and Proximity Imaging of Ac In Vivo With a CZT Gamma Camera: A Proof of Principle With Simulations

Caravaca¹,

Huh²,

Gullberg³

et al. 2022

IEEE Trans. Radiat. Plasma Med. Sci.

View full text Add to dashboard Cite

In vivo imaging of 225 Ac is a major challenge in the development of targeted alpha therapy radiopharmaceuticals due to the extremely low injected doses. In this article, we present the design of a multimodality gamma camera that integrates both proximity and Compton imaging in order to achieve the demanding sensitivities required to image 225 Ac with good image quality. We consider a dual-head camera, each of the heads consisting of two planar cadmium zinc telluride detectors acting as scatterer and absorber for Compton imaging, and with the scatterer practically in contact with the subject to allow for proximity imaging. We optimize the detector's design and characterize the detector's performance using Monte Carlo simulations. We show that Compton imaging can resolve features of up to 1.5 mm for hot-rod phantoms with an activity of 1 µCi, and can reconstruct 3-D images of a mouse injected with 0.5 µCi after a 15-min exposure and with a single bed position, for both 221 Fr and 213 Bi. Proximity imaging is able to resolve two 1 mm-radius sources of less than 0.1 µCi separated by 1 cm and at 1 mm from the detector, as well as it can provide planar images of 221 Fr and 213 Bi biodistributions of the mouse phantom in 5 min.

show abstract

A photon source model for alpha-emitter radionuclides

Sarrut,

Etxebeste,

Létang

2024

Phys. Med. Biol.

View full text Add to dashboard Cite

A Monte Carlo virtual source model that generates photons emitted in the complex decay chain process of alpha-emitter radionuclides is proposed, typically for use during simulation of SPECT image acquisition. Given an alpha-emitter radionuclide, the model extracts from Geant4 databases the photon emission lines from all decaying daughters for both isometric transition and atomic relaxation processes. According to a given time range, abundances and activities in the decay chain are considered thanks to the Bateman equations, taking into account the decay rates and the initial abundances. The proposed source model is evaluated versus analog Monte Carlo simulation. It generates photons with the correct energy and temporal distribution, avoiding the costly Monte Carlo simulation of the complete decay chain. Photons emitted from Bremsstrahlung are ignored, but are not significant for SPECT imaging. As an example for 225Ac, comparison of the proposed model versus a simple source with the two main photon emission lines (218 and 440 keV) show that 2.6 times more particles are simulated and 60% more counts are detected in the images. The proposed model can simulate any alpha-emitter radionuclide available in the Geant4 database. It is available in GATE and ease investigation of imaging gamma rays from alpha-emitters.

show abstract

Estimate of the 225Ac Radioactive Isotope Distribution by Means of DOI Compton Imaging in Targeted Alpha Radiotherapy: A Monte Carlo Simulation

Cited by 4 publications

References 28 publications

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals

Compton and Proximity Imaging of Ac In Vivo With a CZT Gamma Camera: A Proof of Principle With Simulations

A photon source model for alpha-emitter radionuclides

Contact Info

Product

Resources

About

Estimate of the 225Ac Radioactive Isotope Distribution by Means of DOI Compton Imaging in Targeted Alpha Radiotherapy: A Monte Carlo Simulation

Cited by 4 publications

References 28 publications

Coded aperture and Compton imaging for the development of 225Ac‐based radiopharmaceuticals

Coded aperture and Compton imaging for the development of 225Ac‐based radiopharmaceuticals

Compton and Proximity Imaging of Ac In Vivo With a CZT Gamma Camera: A Proof of Principle With Simulations

A photon source model for alpha-emitter radionuclides

Contact Info

Product

Resources

About

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals

Coded aperture and Compton imaging for the development of ²²⁵Ac‐based radiopharmaceuticals