SU-E-T-562: Reducing the Arc Span for CSA VMAT Delivery

Medical Physics
Pamela A MyersN Papanikolaou

Abstract

To dosimetrically evaluate advantages and disadvantages of using multiple, shorter, sub-arcs versus full arc deliveries for treatment of cranio-spinal axis (CSA) irradiation. Five (n=5) cranio-spinal axis irradiation patients were planned using 2 complete arcs, one superior and one inferior; with gantry rotations from 1 to 359 degrees. Due to supine patient setup, each original full arc was then replanned split into two sub arcs with gantry rotations from 1 to 100 and 260 to 359 degrees creating 4 smaller arcs. The PTV was normalized such that 95% received at least 23.4 Gy in 13 fractions. The PTV was evaluated based on conformity number and homogeneity index. The normal structures were evaluated based on maximum and mean doses. Beam on times and monitor units were compared. Averaged over all patients, conformity number was calculated to be approximately 0.86 and 0.82 for full arc and sub arc plans respectively. The homogeneity index was approximately 1.07 and 1.06 for full arc and sub arc plans. This indicates better target conformity but less homogeneous dose distribution for full arc plans as compared with sub arc plans. With the exception of the eyes, each normal structure evaluated had lower maximum doses with subarc plans...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.