SU-E-T-291: Dosimetry of Double Scattered Proton Beam Fields Used for Cranio-Spinal Irradiation

Medical Physics
X SongM Gillin

Abstract

To investigate the effect of source to surface distance on treatment field lateral penumbra width and the consequence of setup error on the dose distribution in the junction between two spinal fields of double scattered proton beams. The CT images of the Spine Phantom from Radiological Physics Center was used to design a double scattered proton beam treatment plan using Varian Eclipse treatment planning system. PTV included spinal cord, vertebral body and part of spinous process. The PTV was divided into superior and inferior parts and two posterior fields were used to cover the targets with the prescribed dose. 2D dose was measured using IBA MatriXX and EBT2 film at a depth close to the center of SOBPs of both the fields located both at the nominal source to axis distance (SAD) of 270 cm and at an extended SAD. The field separation was changed by ±1 mm to study the effect of setup error. The measured and TPS calculated dose distributions in verification plans in a water phantom were compared. The measured 2-D doses agreed very well with planned ones for individual fields. 99% of pixels pass 3%/3 mm dose/distance agreement criteria. The CAX dose differences are within 2%. The 80% to 20% penumbra widths at nominal SAD are 7.4/7....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.