SU-E-T-126: Non-Reference Condition Correction Factor KNR of Typical Radiation Detectors for the Dosimetry of High-Energy Photons

Medical Physics
Ndimofor ChoforDietrich Harder

Abstract

To correct for the deviations of the detector response when typical radiation detectors are used under non-reference conditions, factor kNR was calculated from the known energy dependence of the detector response at photon energies from 10 keV upwards and from clinical photon spectra within a large water phantom beneath a Siemens Primus 6/15 MV linac. A Farmer type ion chamber (NE2571), two TLD detector types and two diodes were investigated. Factor kNR was obtained as the ratio of the weighted responses Yt of a given detector t under reference conditions xref (axial distance r = 0 cm, depth d = 10 cm, field size 10 × 10 cm(2) and SSD = 100 cm) and that under non-reference conditions × (off-axis points and depths for various field sizes); kNR = Yt(xref)/Yt(x). For small field (SF) dosimetry, we evaluated correction factor kNRSF, which refers to small field reference conditions (4 × 4 cm(2) field). For all detectors investigated, the deviations of kNR from unity were highest outside the field, due to prevailing low-energy scatter contributions. For the Farmer chamber and EDP-10 diode, the kNR deviations did not exceed 2%, but were up to 60% for the EDD-5 diode, while kNR values for LiF:Mg,Cu,P and LiF:Mg,Ti deviated at most 15% ...Continue Reading

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.