measurement of stereotactic beam data of 9 mv x-rays using diode detector

نویسندگان

m.t. bahreyni toossi department of medical physics, faculty of medicine, mashhad university of medical sciences, mashhad, iran

a.r. khoshbin khoshnazar

چکیده

background: radiosurgery is a focal brain irradiation technique that delivers, usually in a single session, high dose of ionizing radiation. the presence of lateral electronic disequilibrium and steep dose gradients in small fields demands special attention to the selection of a suitable detector with respect to its size, composition and response. materials and methods : small circular fields were produced by home-made collimators attached to a 9mv neptun 10 pc linac ranging from 12.5mm to 25 mm at isocenter level in 2.5 mm increment. stereotactic beam data including percent depth dose, off axis ratio and output factor were measured using p-type silicon chip detector in a water phantom. beam data were plotted for all available collimator sizes. results: percent depth dose values at depth of 100 cm show 10 percent increase with enlargement of the field sizes from 12.5 mm to 25mm. small overestimation of output factor has been observed using diode detector. conclusion: it is concluded for stereotactic radiosurgery with higher energy photon diode detector could be a good and reasonable choice to measure percent depth dose and off axis ratio. regarding the output factor, it is better to compare the results with those obtained by other detectors. iran . j. radiat. res., 2004 2 (2): 79-84

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Measurement of stereotactic beam data of 9 MV X-rays using diode detector

Background: Radiosurgery is a focal brain irradiation technique that delivers, usually in a single session, high dose of ionizing radiation. The presence of lateral electronic disequilibrium and steep dose gradients in small fields demands special attention to the selection of a suitable detector with respect to its size, composition and response. Materials and Methods : Small circular fields w...

متن کامل

Direct detection of 6 MV x-rays from a medical linear accelerator using a semiconducting polymer diode.

Recently, a new family of low-cost x-radiation detectors have been developed, based on semiconducting polymer diodes, which are easy to process, mechanically flexible, relatively inexpensive, and able to cover large areas. To test their potential for radiotherapy applications such as beam monitors or dosimeters, as an alternative to the use of solid-state inorganic detectors, we present the dir...

متن کامل

The influence of a novel transmission detector on 6 MV x-ray beam characteristics.

The purpose of this work was to investigate the influence of a new transmission detector on 6 MV x-ray beam properties. The device, COMPASS (IBA Dosimetry, Germany), contains 1600 plane parallel ionization chambers with a detector spacing of 6.5 mm and an active volume of 0.02 cm3. Surface dose measurements were carried out using a Markus chamber and radiochromic film for a range of field sizes...

متن کامل

Measurement of laser diode astigmatism using the beam-line method

Roland V. Shack University of Arizona Optical Sciences Center Tucson, Arizona 85721 Abstract. We propose a novel method to measure the astigmatism of laser diodes that is based solely on power measurements and does not require the use of any imaging system. Experimental realization of this method resulted in a sensitive measuring technique. Using it, a linear dependence of astigmatism change on...

متن کامل

Assessment of an Unshielded Electron Field Diode Dosimeter for Beam Scanning in Small- to Medium-Sized 6 MV Photon Fields

Introduction Radiotherapy planning systems require many percentage depth dose (PDD) and profile measurements and there are various dosimeters that can be used to obtain these scans. As dose perturbation is particularly troublesome in smaller photon fields, using a low-perturbation, unshielded electron field diode (EFD) in these fields is of interest. The aim of this work was to investigate the ...

متن کامل

assessment of the efficiency of s.p.g.c refineries using network dea

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

منابع من

با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید


عنوان ژورنال:
iranian journal of radiation research

جلد ۲، شماره ۲، صفحات ۷۹-۸۴

میزبانی شده توسط پلتفرم ابری doprax.com

copyright © 2015-2023