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Dosimetry - Springer Nature

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Last Updated: 03 September 2022

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Voxel-Based Internal Dosimetry for ^177Lu-Labeled Radiopharmaceutical Therapy Using Deep Residual Learning

Purpose In this study, we introduce a deep learning-based voxel-based dosimetry system in which dose maps obtained using the multiple voxel S-value method were used for residual learning. In this study, twenty-two SPECT/CT datasets from seven patients who underwent 177Lu-DOTATATE therapy were used. The dose maps generated from Monte Carlo simulations were used as the reference approach and target images for network preparation, as the reference approach and target images for network preparation. Multiple VSV techniques were used for residual learning and compared to dose charts developed from deep learning. On the dose charts, no significant difference was made between the multiple VSV and DL approach. The multiple VSV strategy, on the other hand, underestimated doses in the low-dose range, but it compensated for the underestimation when the DL approach was initiated. Conclusions: Dose estimation using the deep learningu2013 method was roughly equal to that used in the MC simulation.

Source link: https://doi.org/10.1007/s13139-022-00769-z


Phase II trial demonstrates the efficacy and safety of individualized, dosimetry-based ^177Lu-DOTATATE treatment of NET patients

With a standard schedule of 7. 4 GBq at four occasions, Purpose Radionuclide therapy with 177Lu-DOTATATE is well established for patients with advanced somatostatin receptor-u2013positive neuroendocrine tumors. However, this approach does not consider individual variability that influences the tumor radiation dose or dose to organs at risk. Patients were eligible if they had a progressive, somatostatin receptoru2013positive neuroendocrine tumor with a Ki 67 labeling index of 20%. They were given cycles of 7. 4 GBq of 177Lu-DOTATATE at 10-u00b1 2-week intervals until a predefined radiation dose to the kidneys was achieved. Grade 3u20134 renal cancer in 10% of patients and was mostly hematologic, with no grade 3u20134 renal toxicity reported. Conclusion Individualized therapy with 177Lu-DOTATATE based on renal dosimetry is clearly safe with low toxicity and promising effectiveness, demonstrating the ability to achieve outcomes beyond the recommended route, which should be further investigated in randomized trials.

Source link: https://doi.org/10.1007/s00259-022-05786-w


Practical dosimetry procedure of air kerma for kilovoltage X-ray imaging in radiation oncology using a 0.6-cc cylindrical ionization chamber with a cobalt absorbed dose-to-water calibration coefficient

We developed a simple dosimetry procedure for kilovoltage X-ray beams with a 0. 6-cc cylindrical ionization chamber in this study, as well as the measurements using a 6-cc chamber and a semiconductor device, confirming the procedure with the measurements using the 0. 6-cc chamber. A modified air kerma formalism based on a 0. 6-cc cylindrical ionization chamber air kerma formalism with a cobalt absorbed dose-to-water calibration coefficient was introduced.

Source link: https://doi.org/10.1007/s12194-022-00665-3


Diagnostic and Dosimetry Features of [^64Cu]CuCl_2 in High-Grade Paediatric Infiltrative Gliomas

The Report's Purpose is a paediatric diffuse gliomas are unusual central nervous system neoplasms devoid of effective therapeutic approaches. Novel diagnostic/therapeutic targets can be identified by molecular imaging of tumor metabolism. PDHGG participants' distribution and dosimetry aspects of [64CuCl_2]Cl_2 are investigated in this research, as copper is a key component of cellular metabolism, and its turnover in tumour cells can be increased in tumour cells. PDHGG-related paediatric patients with PDHGG were prospectively recruited, according to the study's findings and methods. Diagnoses included diffuse midline gliomas and diffuse hemispheric gliomas. [64Cu]CuCl_2 accumulation was always concomitant with MRI contrast enhancements and was even greater in the presence of radiological signs of necrosis. Conclusions [64Cu]:CuCl_2 is a well-tolerated radiotracer with robust dosimetric capability, with specific uptake in tumour areas with apparent contrast enhancement and necrosis, implying that blood-u2013brain barrier damage is a pre-requisite for its delivery to intracranial structures.

Source link: https://doi.org/10.1007/s11307-022-01769-3


RPLD-based postal dosimetry audits for radiotherapy hospitals: a full investigation of linear accelerators in the Republic of Korea

The rapid growth of medical radiation and technological advances aimed at high-performance and high-precision radiotherapy necessitates the analysis of existing technologies and the creation of regulatory frameworks for safe use of medical radiation. We conducted a national postal dosimetry audit for the output dose and mechanical accuracy of clinical radiotherapy at medical institutions between 2017 and 2020; the investigation was conducted on the output dose and mechanical integrity of photon beams from 92 institutions.

Source link: https://doi.org/10.1007/s40042-022-00594-9


Biodistribution and dosimetry of the GluN2B-specific NMDA receptor PET radioligand (R)-[^11C]Me-NB1

Background The NMDA receptor, e. g. , plays a crucial role in synaptic transmission in the central nervous system. Although synaptic NMDARs are believed to have shielding properties, the emergence of extrasynaptic NMDARs may lead to excitotoxic reactions related to neuropsychiatric disorders. Methods Four healthy subjects underwent one whole-body PET/MR survey that lasted for more than 120 minutes. In nine passes and six bed positions from head to mid-thigh, subjects were measured in nine passes and six bed positions from head to mid-thigh. Organ equivalent dose coefficients and the effective dose coefficient were estimated using time-integrated activity coefficients and the effective dose coefficient. In virtually all organs except for male's urinary bladder, the urinary bladder was higher than in female. Organ equivalent dose coefficients were also higher in female in nearly all organs except for the urinary bladder. Conclusion The GluN2B-specific radioligand [11C]Me-NB1 was well tolerated with no reported side effects, and there was no reported side effects. Longitudinal studies for neuropsychiatric disorders, including neurodegenerative diseases, are feasible due to the low effective dose coefficient of this radioligand.

Source link: https://doi.org/10.1186/s13550-022-00925-8


Improved accuracy of S-value-based dosimetry: a guide to transition from Cristy–Eckerman to ICRP adult phantoms

The resulting concrete absorbed fractions are based on more realistic human anatomy than those estimated in the stylized, geometrical Cristyu2013Eckerman phantom. We've established a correspondence between source and target tissues defined in the CE phantom and those identified in the ICRP phantoms to help with the change. In comparison to the 23 source and 18 target tissue regions identified in the CE phantom, the ICRP phantom has 79 source regions and 43 target regions in comparison to the 23 source and 18 target tissue regions defined in the CE phantom. The ICRP phantom provides tissue regions with greater anatomical clarity. We have established the relationship between CE and ICRP phantom source and target regions, and we have tried to highlight the ICRP source tissues relevant to radiopharmaceutical therapy. It gives concrete recommendations for porting the total absorbed activity for regions identified in the CE phantom to regions within the ICRP phantoms.

Source link: https://doi.org/10.1186/s40658-022-00485-9


Biodistribution and dosimetry in human healthy volunteers of the PET radioligands [^11C]CHDI-00485180-R and [^11C]CHDI-00485626, designed for quantification of cerebral aggregated mutant huntingtin

It is not yet possible to perform in vivo the measurement of mHTT aggregates in human brain parenchyma. Methods The study of biodistribution and radiation dosimetry was conducted in three healthy volunteers for [11C]CHDI-180R and in three healthy volunteers for [11C]CHDI-626 using sequential whole-body PET-CT. The mean effective dose for [11C]CHDI-180R was 4. 58 u00b1 0. 65 mm u00b1. 00 MBq, with the highest absorption doses for liver, heart wall, and small intestine. Mean ED for [11C] CHDI-626 was 5. 09 u00b1 0. 06 bcsv/MBq with the highest absorption doses for the gallbladder, small intestine, and liver, according to the nicolab: 136 mg. 06/MBq. Human breast PET imaging studies using in vivo PET imaging are recommended [11C]CHDI-180R and [11C]CHDI-626 are safe for in vivo PET imaging. Although [11C]CHDI-180R has promising kinetic properties in the brain, [11C]CHDI-626 is not appropriate for human in vivo mHTT PET due to the likelihood of a radiometabolite accumulation in brain parenchyma.

Source link: https://doi.org/10.1007/s00259-022-05945-z

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions