Abstract：
:Treatment of cervical cancer often involves intracavitary high dose rate (HDR) brachytherapy. Dose delivered to the bladder and rectum are typically estimated using the ICRU reference points. Dose to the sigmoid and small bowel are not estimated, yet these organs typically exhibit significant complication rates. The objective of this study was to estimate dose to the small bowel and sigmoid using CT images. Bladder and rectum dose estimates obtained from the reference point method were also compared to those obtained from CT images. Eighteen CT scans taken before or after treatment of women treated with HDR using ring and tandem applicators were included in this study. The small bowel, sigmoid, bladder and rectum were contoured and the ICRU points were digitized. The minimum dose to 2cc (D2cc ) of each organ was calculated and normalized to % prescribed to Point A. Average D2cc bowel dose was 70%. D2cc bowel dose was significantly higher than both D2cc rectal (27%) and D2cc sigmoid (31%) doses. The average D2cc bladder and rectal doses were 68% (p=NS) and 27% (p<0.001) of prescribed Point A dose. D2cc bowel dose, although significantly higher than rectum and sigmoid, is within an acceptable limit. D2cc bladder and rectum values are either not significantly different from or are significantly lower than ICRU reference values. The results of this study suggest that CT imaging is not necessary for determination of dose to organs at risk. However, image guidance is of value for identifying perforations prior to commencing treatment.
journal_name
Med Physjournal_title
Medical physicsauthors
Lekx-Toniolo KS,Hunter R,Patel M,Voruganti S,Johanson C,Dhamanaskar K,Farrell Tdoi
10.1118/1.2965957subject
Has Abstractpub_date
2008-07-01 00:00:00pages
3408issue
7Part2eissn
0094-2405issn
2473-4209journal_volume
35pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:For diagnostic ultrasound imaging, as in computed tomography, a feature of prime importance is the detection of focal lesions of varying size and contrast (echo amplitude) from surrounding tissue. This study describes a new tissue-stimulating phantom which has been used to measure the threshold detection of varying co...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595218
更新日期：1982-01-01 00:00:00
abstract：PURPOSE:To design and quantify the shielding efficacy of an inner Borated Polyethylene (BPE)wall for a 15 MV linac in a low energy vault. METHODS:A Varian TrueBeam linac with a maximum photon energy of 15 MV was installed in asmaller, preexisting vault. This vault originally housed a low-energy machine and did not hav...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735334
更新日期：2012-06-01 00:00:00
abstract：:An overall practical dosimetric study of a 10-MV photon beam produced by a Varian Clinac-18 linear accelerator is presented. In particular measurements were made to provide data which could be utilized in computerized dosage calculations using the concept of dividing the radiation beam into primary and scatter compone...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594311
更新日期：1977-03-01 00:00:00
abstract：:The dosimetry protocols DIN 6800-2 and AAPM TG-51, both based on the absorbed dose to water concept, are compared in their theoretical background and in their application to electron dosimetry. The agreement and disagreement in correction factors and energy parameters used in both protocols will be shown and discussed...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1414008
更新日期：2001-11-01 00:00:00
abstract：:In prostate seed implants, radioactive seeds are implanted into the prostate through a guiding needle with the help of a template and real-time imaging. The ideal locations of the guiding needles and the relative positions of the seeds in each needle are determined before the implantation under the assumption that the...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598971
更新日期：2000-05-01 00:00:00
abstract：PURPOSE:The authors describe a design for prepatient region of interest attenuators (ROIAs) to reduce dose area product (DAP) for clinical use. The authors describe a model to predict DAP values from x-ray technique parameters recorded during a clinical procedure for image sequences obtained in the presence or absence ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4903898
更新日期：2015-01-01 00:00:00
abstract：PURPOSE:To compare optimization characteristics, plan quality, and treatment delivery efficiency between total marrow irradiation (TMI) plans using the new TomoTherapy graphic processing unit (GPU) based dose engine and CPU/cluster based dose engine. METHODS:Five TMI plans created on an anthropomorphic phantom were op...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4810936
更新日期：2013-07-01 00:00:00
abstract：:We propose the use of conic and cubic surface equations (surfaces of second and third order) to directly approximate the dual-energy equations (the integral equations for the dual-energy log-signal functions, i.e., the negative logarithms of the relative detector signals, considered as functions of the basis-material ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596512
更新日期：1990-05-01 00:00:00
abstract：PURPOSE:To automatically and efficiently segment the lesion area of the colonoscopy polyp image, a polyp segmentation method has been presented. METHODS:An ensemble model of pretrained convolutional neural networks was proposed, using Unet-VGG, SegNet-VGG, and PSPNet. Firstly, the Unet-VGG is obtained by the first 10 ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13865
更新日期：2019-12-01 00:00:00
abstract：PURPOSE:In order to build up a reliable dose monitoring system for boron neutron capture therapy (BNCT) applications at the TRIGA reactor in Mainz, a computer model for the entire reactor was established, simulating the radiation field by means of the Monte Carlo method. The impact of different source definition techni...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4897242
更新日期：2014-11-01 00:00:00
abstract：PURPOSE:Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4829513
更新日期：2013-12-01 00:00:00
abstract：PURPOSE:To assess and compare the dosimetric impact of dynamic multileaf collimator (DMLC) tracking and gating as motion correction strategies to account for intrafraction motion during conventionally fractionated prostate radiotherapy. METHODS:A dose reconstruction method was used to retrospectively assess the dose d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892605
更新日期：2014-09-01 00:00:00
abstract：PURPOSE:The measurement of malignant pleural mesothelioma is critical to the assessment of tumor response to therapy. Current response assessment standards utilize summed linear measurements acquired on three computed tomography (CT) sections. The purpose of this study was to evaluate manual area measurements as an alt...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4810940
更新日期：2013-08-01 00:00:00
abstract：PURPOSE:This paper describes the clinical implementation and medical commissioning of the MedAustron Particle Therapy Accelerator (MAPTA) for non-isocentric scanned proton beam treatments. METHODS:Medical physics involvement during technical commissioning work is presented. Acceptance testing procedures, including adv...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13928
更新日期：2020-02-01 00:00:00
abstract：:We attempt to select an optimal value of regularization parameter in the optimization problems for intensity-modulated radiotherapy which are solved using a variational regularization technique. We apply to inverse treatment planning the L-curve method which was developed to determine the regularization parameter in t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1949750
更新日期：2005-08-01 00:00:00
abstract：PURPOSE:Photoacoustic imaging has proven to be able to detect vascularization-driven optical absorption contrast associated with tumors. In order to detect breast tumors located a few centimeter deep in tissue, a sensitive ultrasound detector is of crucial importance for photoacoustic mammography. Further, because the ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4792462
更新日期：2013-03-01 00:00:00
abstract：PURPOSE:Low-dose CT has attracted increasing attention due to growing concerns about radiation exposure in medical scans. However, the frugal use of x-ray radiation inevitably reduces the quality of the CT images, introducing artifacts such as noise and streaks which make the reconstructed images difficult to read in c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4736528
更新日期：2012-08-01 00:00:00
abstract：PURPOSE:The Acuros XB (AXB) Advanced Dose algorithm (Varian Medical Systems) represents a dramatic shift in clinical photon dose calculation methodology from pencil-beam superposition/convolution methods. Early studies evaluating the accuracy of the algorithm in lung have found good agreement with both measurement and ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735574
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Temporal subtraction is used to detect the interval change in chest radiographs and aid radiologists in patient diagnosis. This method registers two temporally different images by geometrically warping the lung region, or "lung mask," of a previous radiographic image to align with the current image. The gray le...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3259712
更新日期：2009-12-01 00:00:00
abstract：:Positron emission tomography (PET) is increasingly considered as an effective imaging method to support several stages of radiation therapy. The combined usage of functional and morphological imaging in state-of-the-art PET/CT scanners is rapidly emerging to support the treatment planning process in terms of improved ...
journal_title：Medical physics
pub_type： 杂志文章,评审
doi：10.1118/1.4935869
更新日期：2015-12-01 00:00:00
abstract：PURPOSE:The aim of this study is to understand the characteristics of secondary electrons generated from the interaction of gold nanoparticles (GNPs) with x-rays as a function of nanoparticle size and beam energy and thereby further the understanding of GNP-enhanced radiotherapy. METHODS:The effective range, deflectio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3539623
更新日期：2011-02-01 00:00:00
abstract：PURPOSE:Monte Carlo (MC) simulation can be used for accurate electron beam treatment planning and modeling. Measurement of large electron fields, with the applicator removed and secondary collimator wide open, has been shown to provide accurate simulation parameters, including asymmetry in the measured dose, for the fu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3592640
更新日期：2011-06-01 00:00:00
abstract：PURPOSE:The purpose of this study is to estimate the effect of edema, developed during implant procedure, on tumor cell surviving fraction(SF) and tumor control probability(TCP) in the patients of prostate cancer who underwent 131 Cs permanent seed implants. METHODS:The impact of edema on SF and TCP, was calculated us...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735061
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The ability to monitor intrafractional tumor motion is essential for radiation therapy of thoracic and abdominal tumors. This study aims to develop a method to track lung tumor motion using intrafractional continuous ultrasound (US) and periodic cone-beam projection images (CBPI). METHODS:Time-sequenced b-mode...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13104
更新日期：2018-10-01 00:00:00
abstract：:The relative sensitivity of the half-value layer (HVL) method as a quality index for megavoltage x-ray beams is examined by theoretical calculation and experimental measurements for 4-, 6-, 10-, and 25-MV x-ray beams. It is shown that lower atomic number materials are more sensitive to beam quality changes than higher...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595794
更新日期：1985-01-01 00:00:00
abstract：PURPOSE:Cardiac motion is typically not accounted for during pretreatment imaging for central lung and mediastinal tumors. However, cardiac induced tumor motion averages 5.8 mm for esophageal tumors and 3-5 mm for some lung tumors, which can result in positioning errors. Our aim is to reduce both cardiac- and respirato...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13670
更新日期：2019-09-01 00:00:00
abstract：:Skin entrance doses of patients undergoing interventional x-ray procedures are capable of causing skin damage and should be monitored routinely. Single TLD chips are not suitable because the location of maximum skin exposure cannot be predicted. Most photographic films are too sensitive at diagnostic x-ray energies fo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597973
更新日期：1997-10-01 00:00:00
abstract：:The gamma index is a tool that compares a dose distribution with a reference distribution by combining dose-difference and distance-to-agreement criteria. It has been widely used for ten years despite its high computational cost. This cost is due to both a search process for each reference point and the necessity to r...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3070546
更新日期：2009-03-01 00:00:00
abstract：:The dosimetry for radiocolloid therapy of cystic craniopharyngiomas is investigated. Analytical calculations based on the Loevinger and the Berger formulas for electrons and photons, respectively, are compared with Monte Carlo simulations. The role of the material of which the colloid introduced inside the craniophary...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1599653
更新日期：2003-09-01 00:00:00
abstract：PURPOSE:One limitation of positron emission tomography (PET) imaging of the torso is patient motion. Motion-compensated image reconstruction (MCIR) is one method employed to reduce the deleterious effects of motion. Existing MCIR algorithms use a single sensitivity correction term, which provides inexact normalization ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3611041
更新日期：2011-09-01 00:00:00
