عنوان

Metal Filled Carbon Nanotubes in Radiation Therapy:

شماره

TLpq2419134721

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Metal Filled Carbon Nanotubes in Radiation Therapy:

نام عام مواد

[Thesis]

نام نخستين پديدآور

Ashmeg, Sarah

عنوان اصلي به قلم نويسنده ديگر

Dose Enhancement Effect

نام ساير پديدآوران

Eisenbraun, Eric

نام ناشر، پخش کننده و غيره

State University of New York at Albany

تاریخ نشرو بخش و غیره

2020

نام خاص و کميت اثر

117

جزئيات پايان نامه و نوع درجه آن

Ph.D.

کسي که مدرک را اعطا کرده

State University of New York at Albany

امتياز متن

2020

متن يادداشت

In this work, the radiation dose enhancement is studied using a novel method and material that has not been widely investigated, at the time of this publication. Radiation dose enhancement is a useful technique in the field of radiation therapy, especially when dealing with radioresistant cells. Ideally, it increases the dose to the desired site with no additional damage to organs at risk. Currently, gold nanoparticles are the most desired radiation dose enhancers, due to the biocompatibility and inertness of gold. However, gold is expensive and gold nanoparticles experience self-absorption of secondary electrons, limiting the level of achieved radiation dose enhancement. Furthermore, after injection, most of the gold nanoparticles are found in the vasculature, rather than inside the cells and in proximity to DNA, as would be desired. Carbon nanotubes have unique physical properties that could make them superior to other nanoparticles, including better cell permeability, owing to their needle-like shape. In addition, due to their honeycomb-like structure, secondary electrons can escape without experiencing self-absorbing, which increases the radiation dose in the region. Also, both the outside walls and the hollow inside of the nanotubes can be utilized simultaneously, allowing attachment and filling of various materials. The hypothesis is using copper filled carbon nanotubes, significant levels of radiation dose enhancement can be achieved. This dose enhancement would be energy dependent, such that it increases with decreasing the energy of x-ray beams. Also, we expect the dose increase to reduce with increasing the distance from the copper-filled carbon nanotubes. In this research, we have filled multi-walled carbon nanotubes with copper and measured the radiation enhancement effect in a water phantom. The effect of adding pure multi-walled carbon nanotubes is also studied and compared to the effect of adding same amount of graphite powder to water phantom. The study was conducted using several setups and several x-ray beam energies in the MeV range with different dosimetry devices. The results show a significant dose increase when copper filled carbon nanotubes are added to water. The radiation dose enhancement ratios are calculated for each set of measurements and the highest value is 1.025 for 2.5 MV beam. Pure multiwalled carbon nanotubes also enhance the dose, which is not expected from classical models. The results show that the dose enhancement value is energy dependent and varies with the point of measurement, while no dose enhancement is observed when synthetic graphite is used. The underlying theory explaining this phenomenon is not well understood, but we hypothesize that the increase of dose can be due to an increase of the probability of Compton scattering due to the unique physical properties that carbon nanotubes possess. In addition, the increase of dose could be due to an increase of electron-electron interaction between secondary electrons and electrons in nanotubes because of the large high aspect ratio of the nanotubes. This experimental study shines light on an unexplored effect and introduces a new approach to assess the radiation dose enhancement. All Au-NPs dose enhancement results are from Monte Carlo simulations and involve dose increases in the vicinity of the nanoparticles, while in this study the dose increase is measured downstream from the cube that contains the copper filled and pure carbon nanotubes. Due to these differences, a direct quantitative comparison between the data is not possible.

موضوع مستند نشده

Biomedical engineering

موضوع مستند نشده

Nanoscience

مستند نام اشخاص تاييد نشده

Ashmeg, Sarah

مستند نام اشخاص تاييد نشده

Eisenbraun, Eric

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y