Abstract：
:Using a plane-parallel advanced Markus ionization chamber and a stack of water-equivalent solid phantom blocks, percentage surface and build-up doses of Elekta 6 MV flattening filter (FF) and flattening-filter-free (FFF) beams were measured as a function of the phantom depth for field sizes ranging from 2 × 2 to 10 × 10 cm2 . It was found that the dose difference between the FF and the FFF beams was relatively small. The maximum dose difference between the FF and the FFF beams was 4.4% at a depth of 1 mm for a field size of 2 × 2 cm2 . The dose difference was gradually decreased while the field size was increased up to 10 × 10 cm2 . The measured data were also compared to published Varian FF and FFF data, suggesting that the percentage surface and build-up doses as well as the percentage dose difference between FF and FFF beams by our Elekta linac were smaller than those by the Varian linac.
journal_name
J Appl Clin Med Physjournal_title
Journal of applied clinical medical physicsauthors
Imae T,Takenaka S,Watanabe Y,Aoki A,Matsuda K,Sasaki K,Saegusa S,Nawa K,Nakagawa K,Abe Odoi
10.1002/acm2.13094subject
Has Abstractpub_date
2020-12-01 00:00:00pages
334-339issue
12issn
1526-9914journal_volume
21pub_type
杂志文章abstract：:Doses in Leksell GammaPlan (Elekta, Stockholm, Sweden) are calculated for each shot by summing the contribution from the 201 radiation beams emitted by the Gamma Knife (Elekta), weighted for attenuation in the tissue traversed. The patient's head is modeled based on 24 skull measurements, from which the depth to the c...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v8i3.2377
更新日期：2007-07-17 00:00:00
abstract：:This study aims to evaluate the potential jaw-tracking advantage using control point sequences of volume volumetric modulated arc therapy (VMAT) planning. VMAT plans for patients with prostate and head and neck (H&N) cancers were converted into new static arc (SA) plans. The SA plan consisted of a series of static fie...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v15i2.4625
更新日期：2014-03-06 00:00:00
abstract：:In radiation therapy, a secondary independent dose verification is an important component of a quality control system. Mobius3D calculates three-dimensional (3D) patient dose using reference beam data and a collapsed cone convolution algorithm and analyzes dose-volume histogram automatically. There are currently no pu...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12572
更新日期：2019-05-01 00:00:00
abstract：PURPOSE:The GammaPod is a dedicated prone breast stereotactic radiosurgery (SRS) machine composed of 25 cobalt-60 sources which rotate around the breast to create highly conformal dose distributions for boosts, partial-breast irradiation, or neo-adjuvant SRS. We describe the development and validation of a patient-spec...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12778
更新日期：2019-12-01 00:00:00
abstract：PURPOSE:Volumetric modulated arc therapy (VMAT) is gaining popularity for stereotactic treatment of lung lesions for medically inoperable patients. Due to multiple beamlets in delivery of highly modulated VMAT plans, there are dose delivery uncertainties associated with small-field dosimetry error and interplay effects...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12878
更新日期：2020-07-01 00:00:00
abstract：:Stereotactic body radiation therapy (SBRT) has been increasingly used as an efficacious treatment modality for early-stage non-small cell lung cancer. The accuracy of dose calculations is compromised due to the presence of inhomogeneity. For the purpose of a consistent prescription, radiation doses were calculated wit...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i2.4011
更新日期：2013-03-04 00:00:00
abstract：:The accuracy of the CyberKnife Synchrony Respiratory Tracking System (SRTS) is considered to be patient-dependent because the SRTS relies on an individual correlation between the internal tumor position (ITP) and the external marker position (EMP), as well as a prediction method to compensate for the delay incurred to...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i1.5049
更新日期：2015-01-08 00:00:00
abstract：:Substantial disagreement exists over appropriate PET segmentation techniques for non-small cell lung cancer. Currently, no segmentation algorithm explicitly considers tumor motion in determining tumor borders. We developed an automatic PET segmentation model as a function of target volume, motion extent, and source-to...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v15i1.4600
更新日期：2014-01-06 00:00:00
abstract：:Many head-and-neck cancer (HNC) patients treated with radiotherapy suffer significant anatomical changes due to tumor shrinkage or weight loss. The purpose of this study was to assess dose changes over target volumes and organs at risk during intensity-modulated radiotherapy for HNC patients. Sixteen HNC IMRT patients...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v13i6.3723
更新日期：2012-11-08 00:00:00
abstract：PURPOSE:To provide insight into the types of questions asked to medical physicists by patients during one-on-one physicist-patient consults at one institution. MATERIALS AND METHODS:Medical physicists trained in patient communication techniques met with patients to provide an overview of the treatment planning and del...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12942
更新日期：2020-08-01 00:00:00
abstract：:Optimal choice of beam energy in radiation therapy is easy in many well-documented cases, but less obvious in some others. Low-energy beams may provide better conformity around the target than their high-energy counterparts due to reduced lateral scatter, but they also contribute to overdosage of peripheral normal tis...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v10i4.3012
更新日期：2009-09-03 00:00:00
abstract：:The purpose of the present study was to use a kilovoltage imaging device to measure interfractional and intrafractional setup deviations in patients with head-and-neck or brain cancers receiving intensity-modulated radiotherapy (IMRT) treatment. Before and after IMRT treatment, approximately 3 times weekly, 7 patients...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v8i4.2439
更新日期：2007-09-24 00:00:00
abstract：:In Winston-Lutz (WL) tests, the isocenter of a linear accelerator (linac) is determined as the intersection of radiation central axes (CAX) from multiple gantry, collimator, and couch angles. It is well known that the CAX can wobble due to mechanical imperfections of the linac. Previous studies suggested that the wobb...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i1.5792
更新日期：2016-01-08 00:00:00
abstract：:A spreadsheet-based model for economically characterizing the operation of a radiation treatment program has been used to perform a quantitative financial analysis of scheduled and unscheduled downtime. The incremental cost of downtime is broken down into three categories: remuneration of in-house or third party servi...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v1i2.2647
更新日期：2000-04-01 00:00:00
abstract：PURPOSE:Segmentation of liver organ and tumors from computed tomography (CT) scans is an important task for hepatic surgical planning. Manual segmentation of liver and tumors is tedious, time-consuming, and biased to the clinician experience. Therefore, automatic segmentation of liver and tumors is highly desirable. It...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.13003
更新日期：2020-10-01 00:00:00
abstract：:Dental amalgams are a common source of artifacts in head and neck (HN) images. Commercial artifact reduction techniques have been offered, but are substantially ineffectual at reducing artifacts from dental amalgams, can produce additional artifacts, provide inaccurate HU information, or require extensive computation ...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12922
更新日期：2020-08-01 00:00:00
abstract：:In this project, we investigated the use of an electronic portal imaging device (EPID), together with the treatment planning system (TPS) and MLC log files, to determine the delivered doses to the patient and evaluate the agreement between the treatment plan and the delivered dose distribution. The QA analysis results...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i3.5283
更新日期：2015-05-08 00:00:00
abstract：:Radiographic film dosimetry provides fast, convenient 2-D dose distributions, but is challenged by the dependence of film response on scatter conditions (i.e., energy dependence). Verification of delivered dose in the surface buildup region is important for intensity modulated radiation therapy (IMRT) when volumes of ...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v9i4.2782
更新日期：2008-10-24 00:00:00
abstract：PURPOSE:The goal of this study was to find the optimal combination of collimator, photopeak and scatter correction for 177 Lutetium (177 Lu) SPECT/CT imaging. METHODS:Three experiments [sphere-to-background ratios (SBR) 50:1, 10:1, and 2:1] were performed with the NEMA Image Quality phantom filled with 177 Lu-trichlor...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12991
更新日期：2020-09-01 00:00:00
abstract：PURPOSE:Multiple metrics are proposed to characterize and compare the complexity of helical tomotherapy (HT) plans created for different treatment sites. METHODS:A cohort composed of 208 HT plans from head and neck (105), prostate (51) and brain (52) tumor sites was considered. For each plan, 14 complexity metrics wer...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12895
更新日期：2020-07-01 00:00:00
abstract：BACKGROUND AND PURPOSE:The purpose of this study of pancreatic cancer patients treated with respiratory-guided stereotactic body radiotherapy (SBRT) on a standard linac was to investigate (a) the intrafractional relationship change (IRC) between a breathing signal and the tumor position, (b) the impact of IRC on the de...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12841
更新日期：2020-03-01 00:00:00
abstract：PURPOSE:Although breast density is considered a strong risk factor of breast cancer, its quantitative assessment is difficult. To investigate a quantitative method of measuring breast density using dual-energy mammographic imaging with central digital breast tomosynthesis in physically uniform and nonuniform phantoms. ...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1002/acm2.12618
更新日期：2019-06-01 00:00:00
abstract：:Traditional quality assurance checks of a patient's radiation therapy plan involve printing out treatment parameters from the treatment planning system and the "record and verify" (R&V) system and visually checking the information for one-to-one correspondence. In a paperless environment, one can automate this process...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v10i1.2905
更新日期：2009-01-27 00:00:00
abstract：:The purpose of this study was to develop and validate cardiac computed tomog-raphy (CT) quantitative analysis software with a patient-specific, 17-segment myocardial model that uses electrocardiogram (ECG)-gated cardiac CT images to differentiate between normal controls and severe aortic stenosis (AS) patients. ECG-ga...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v17i5.6237
更新日期：2016-09-08 00:00:00
abstract：:The image-guided radiotherapy technique (IGRT) makes use of imaging devices to verify the positions of the target volume and organs at risk during the treatment sessions. In this work we evaluate the image quality provided by an imaging system based on a kilovoltage cone-beam CT, and explore its ability to perform IGR...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v14i1.3888
更新日期：2013-01-07 00:00:00
abstract：:A quality assurance (QA) procedure was developed to evaluate the congruence between the cone-beam computed tomography (CBCT) image center and the radiation isocenter on a Varian Trilogy linac. In contrast to the published QA procedures, this method did not require a ball bearing (BB) phantom to be placed exactly at th...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v11i4.3297
更新日期：2010-07-02 00:00:00
abstract：:The American Association of Physicists in Medicine Task Group 36 (AAPM TG-36) data can be used to estimate peripheral dose (PD) distributions outside the primary radiation field. However, the report data does not apply to linear accelerators equipped with a multileaf collimator (MLC) and universal wedge (UW). Tertiary...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v3i4.2554
更新日期：2002-10-01 00:00:00
abstract：:Breast treatments are becoming increasingly complex as the use of modulated and partial breast therapies becomes more prevalent. These methods are predicated on accurate and precise positioning for treatment. However, the ability to quantify intrafraction motion has been limited by the excessive dose that would result...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v15i6.4957
更新日期：2014-11-08 00:00:00
abstract：:Hepatic encephalopathy (HE) is normally diagnosed by neuropsychological (NP) tests, which are not very specific and do not reveal the underlying pathology. Magnetic resonance imaging (MRI) and spectroscopy (MRS) of the brain offer alternative and possibly more specific markers for HE. These methods were applied in con...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v7i1.2151
更新日期：2006-01-01 00:00:00
abstract：:The purpose of this study was to demonstrate that Monte Carlo treatment planning systems require tissue characterization (density and composition) as a function of CT number. A discrete set of tissue classes with a specific composition is introduced. In the current work we demonstrate that, for megavoltage photon radi...
journal_title：Journal of applied clinical medical physics
pub_type： 杂志文章
doi：10.1120/jacmp.v16i5.5586
更新日期：2015-09-08 00:00:00
