Abstract

Alena Tensor is a recently discovered class of energy-momentum tensors that provides mathematical framework in which, as demonstrated in previous publications, the description of a physical system in curved spacetime and its description in flat spacetime with fields are equivalent. The description of a system with electromagnetic field based on Alena Tensor can be used to reconcile physical descriptions. (1) In curvilinear description, Einstein Field equations were obtained with Cosmological Constant related to the invariant of the electromagnetic field tensor, which can be interpreted as negative pressure of vacuum, filled with electromagnetic field. (2) In classical description for flat spacetime, three densities of four-forces were obtained: electromagnetic, against gravity (counteraction to gravitational free-fall), and the force responsible for the Abraham-Lorentz effect (radiation reaction force). Obtained connection of Einstein tensor with gravity and radiation reaction force, after transition to curvilinear description, excludes black hole singularities. There was obtained Lagrangian density and generalized canonical four-momentum, containing electromagnetic four-potential and a term responsible for the other two forces. In this description charged particles cannot remain at complete rest and should have spin, their energy results from the existence of energy of magnetic moment and the density of this energy is part of the Poynting four-vector. The distribution of charged matter was expressed as polarization-magnetization stress-energy tensor, what may explain why gravity is invisible in QED. 3) In quantum picture, QED Lagrangian density simplification was obtained, and the Dirac, Schrödinger and Klein-Gordon equations may be considered as approximations of the obtained quantum solution. Farther use of Alena Tensor in unification applications was also discussed.

• Book : 100(1)
• Pub. Date : 2025
• Page : pp.015018
• Keyword :

• Book : 242(1)
• Pub. Date : 2025
• Page : pp.115890
• Keyword :

• Book : 266()
• Pub. Date : 2025
• Page : pp.120470
• Keyword :

Abstract

OBJECTIVE

To evaluate the radiation dose to personnel locations during simulated head and limb scans with a novel equine standing CT (sCT) system.

METHODS

Measurements were made with the use of a helical fan beam sCT system (Equina; Asto CT Inc). Scatter radiation was measured in different positions in the sCT room to mimic the location of the control operator, horse handler, and lead rope handler during simulated equine head and limb imaging. Operator/handler dose was quantified at each location using entrance air kerma measured with a spherical ionization chamber and electrometer.

RESULTS

Radiation dose to the control operator, horse handler, and lead rope handler locations wearing a lead apron during simulated head imaging was 13.3, 3.5, and 6.8 µGy, respectively. Radiation dose to the control operator location wearing a lead apron was 1.3 µGy, and dose to the lead rope handler location wearing a lead apron was 0.2 and 5.4 µGy during simulated pelvic limb and thoracic limb imaging, respectively.

CONCLUSIONS

With the more widespread clinical use of equine sCT units in clinical practice, there is concern for increased risk of radiation exposure to personnel who stay in the sCT room during scanning. The control operator location had the highest dose during simulated head imaging, and the lead rope handler location in thoracic limb sCT had the highest dose during simulated limb imaging. Limiting the number of personnel in the sCT room, rotating personnel between handler positions, increasing operator distance from the scanner, and using lead shields and eyeglasses are recommended.

CLINICAL RELEVANCE

Our findings suggest that scanning large numbers of horses per year with the Asto CT Equina would not lead to occupational radiation exposure above the recommended safe threshold for handlers using lead shields and eyeglasses.

• Book : 263(1)
• Pub. Date : 2025
• Page : pp.63-70
• Keyword :

• Book : 81(1)
• Pub. Date : 2025
• Page : pp.n/a
• Keyword :

• Book : 266()
• Pub. Date : 2025
• Page : pp.120504
• Keyword :

• Book : 242(pd)
• Pub. Date : 2025
• Page : pp.116086
• Keyword :

• Book : 179()
• Pub. Date : 2025
• Page : pp.105527
• Keyword :

• Book : 1072()
• Pub. Date : 2025
• Page : pp.170145
• Keyword :

Abstract

Urogenital tuberculosis is one of common sites of extrapulmonary tuberculosis. A 60-year-old man with an elevated prostate-specific antigen level underwent multiparametric MRI, which revealed abnormal signals in the prostate. However, the ⁶⁸Ga-PSMA PET/CT results were unrevealing. Subsequent ⁶⁸Ga-FAPI PET/CT imaging revealed intense radioactivity uptake in the prostate and mild radioactivity uptake in the left kidney, which was eventually proven due to tuberculosis.

• Book : 50(1)
• Pub. Date : 2025
• Page : pp.98-100
• Keyword :