| 1. |
- de Las Heras Gala, Hugo, et al.
(författare)
-
Quality control in cone-beam computed tomography (CBCT): EFOMP-ESTRO-IAEA protocol
- 2017
-
Rapport (refereegranskat)abstract
- Quality control of cone-beam computed tomography (CBCT) systems is an essential part of quality assurance to periodically check that quality requirements are met, reduce uncertainties and errors and reduce the likelihood of accidents and incidents. Radiation exposure levels must be measured to ensure that patient doses associated with CBCT examinations are kept as low as reasonably achievable consistent with the required diagnostic information. The main purpose of this document is to present procedures for quality control of CBCT systems used for dental, radiotherapy, interventional radiology and guided surgery applications.
|
|
| 2. |
- de Las Heras Gala, Hugo, et al.
(författare)
-
Quality control in cone-beam computed tomography (CBCT) EFOMP-ESTRO-IAEA protocol (summary report)
- 2017
-
Ingår i: Physica medica (Testo stampato). - : Elsevier BV. - 1120-1797 .- 1724-191X. ; 39, s. 67-72
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the guideline presented in this article is to unify the test parameters for image quality evaluation and radiation output in all types of cone-beam computed tomography (CBCT) systems. The applications of CBCT spread over dental and interventional radiology, guided surgery and radiotherapy. The chosen tests provide the means to objectively evaluate the performance and monitor the constancy of the imaging chain. Experience from all involved associations has been collected to achieve a consensus that is rigorous and helpful for the practice. The guideline recommends to assess image quality in terms of uniformity, geometrical precision, voxel density values (or Hounsfield units where available), noise, low contrast resolution and spatial resolution measurements. These tests usually require the use of a phantom and evaluation software. Radiation output can be determined with a kerma-area product meter attached to the tube case. Alternatively, a solid state dosimeter attached to the flat panel and a simple geometric relationship can be used to calculate the dose to the isocentre. Summary tables including action levels and recommended frequencies for each test, as well as relevant references, are provided. If the radiation output or image quality deviates from expected values, or exceeds documented action levels for a given system, a more in depth system analysis (using conventional tests) and corrective maintenance work may be required.
|
|
| 3. |
- Delis, Costas, et al.
(författare)
-
AtHESPERIN : a novel regulator of circadian rhythms with poly(A)-degrading activity in plants
- 2016
-
Ingår i: RNA Biology. - : Informa UK Limited. - 1547-6286 .- 1555-8584. ; 13:1, s. 68-82
-
Tidskriftsartikel (refereegranskat)abstract
- We report the identification and characterization of a novel gene, AtHesperin (AtHESP) that codes for a deadenylase in Arabidopsis thaliana. The gene is under circadian clock-gene regulation and has similarity to the mammalian Nocturnin. AtHESP can efficiently degrade poly(A) substrates exhibiting allosteric kinetics. Size exclusion chromatography and native electrophoresis coupled with kinetic analysis support that the native enzyme is oligomeric with at least 3 binding sites. Knockdown and overexpression of AtHESP in plant lines affects the expression and rhythmicity of the clock core oscillator genes TOC1 and CCA1. This study demonstrates an evolutionary conserved poly(A)-degrading activity in plants and suggests deadenylation as a mechanism involved in the regulation of the circadian clock. A role of AtHESP in stress response in plants is also depicted.
|
|
