Purpose: Diffusion kurtosis imaging (DKI) is an MRI method related to diffusion imaging (DWI) that is distinguished by a non-Gaussian calculation of water particles movements in tissues. The aim of the study was to assess DKI advantage over DWI in differentiating benign and malignant liver lesions.
Material And Methods: Analysis included prospectively acquired group of 83 patients referred consecutively for 3T-MRI liver tumor examination, with 95 liver lesions (31 benign, 59 malignant).
Periodic intermediate checks on the equipment used for calibration activity accredited for the conformity with the international norm ISO/IEC 17025 are an essential issue for monitoring the validity of calibration laboratory's results. These checks should be carried out according to a procedure defined by each accredited laboratory. The results of these checks should not exceed the acceptance criteria established in the laboratory and statistical techniques shall be applied to the reviewing of the results.
View Article and Find Full Text PDFIntroduction: In order to improve the efficacy of intravoxel incoherent motion (IVIM) parameters in characterising specific tissues, a new concept is introduced: the perfusion-diffusion ratio (PDR), which expresses the relationship between the signal () decline rate as a result of IVIM and the rate of signal () decline due to diffusion. The aim of this study was to investigate this novel approach in the differentiation of solid primary liver lesions. .
View Article and Find Full Text PDFPurpose: The calculation model for the integral quality monitor (IQM) system does not take into account the characteristics of the HD120 multileaf collimator (MLC), which some Varian accelerators are equipped with. Some treatment plans prepared with this collimator are characterized by a high level of modulation. The aim of the work was to prepare a model for that collimator and to determine the influence of modulation on results of the verification carried out with the use of IQM system.
View Article and Find Full Text PDFRep Pract Oncol Radiother
April 2020
Background: The No Action Protocol (NAL) was used to diminish the systematic set-up error. Recently, owing to the development of image registration technologies, the on-line positioning control is more often used. This method significantly reduces the CTV-PTV margin at the expense of the lengthening of a treatment session.
View Article and Find Full Text PDFThis paper describes the role of the Polish Secondary Standard Dosimetry Laboratory (SSDL) in quality assurance in radiotherapy by means of providing calibration of ionisation chambers, TLD postal dosimetry audits and end-to-end audits for radiation therapy. A historical review of the methods and results are presented. The influence of the SSDL in Warsaw on radiation protection of patients in Poland is discussed.
View Article and Find Full Text PDFBackground: A non-invasive tool for the assessment of ulcerative colitis (UC) activity is needed for treatment control.
Purpose: To determine the efficacy of intravoxel incoherent motion (IVIM) in assessing inflammatory activity in UC.
Material And Methods: In this prospective study, 20 adult patients underwent 3.
Volumetric Modulated Radiotherapy (VMAT) implementation requires additional Quality Assurance (QA) tests to assure stable machine performance especially in terms of dynamic parameters synchronization. The lack of a twin machine for TrueBeam led us to the investigation of backup workflow with Clinacs 2300C/D. These Clinacs were upgraded to make them VMAT-enabled.
View Article and Find Full Text PDFPurpose: Interfraction tumor setup variations in radiotherapy are often reduced with image guidance procedures. Clinical target volume (CTV)-planning target volume (PTV) margins are then used to deal with residual errors. We have investigated characterization of setup errors in patient populations with explicit modelling of occurring interfraction time trends.
View Article and Find Full Text PDFPurpose: The objective was to optimise the number of b-values for diffusion kurtosis imaging (DKI) of the liver and pancreas in MR examinations to ensure reliable results with the shortest possible acquisition time.
Methods: Twenty healthy volunteers underwent DKI at 3.0 T Siemens Magnetom Skyra using 7 b-values (b = 0, 200, 500, 750, 1000, 1500, 2000 s/mm).
Purpose: To optimise the intravoxel incoherent motion (IVIM) imaging of the liver on a 3.0T scanner by assessing parameter reproducibility on free-breathing (FB) and respiratory-triggered (RT) sequences acquired with different numbers of signal averages (NSA).
Material And Methods: In this prospective study 20 subjects (M/F: 10/10; age: 25-62 years, mean: 39 years) underwent IVIM magnetic resonance imaging (MRI) on a 3.
Aim: The aim of the study was to analyze the long-term stability of electron beams generated by the Novac11™ IORT accelerator.
Background: Novac11™ (NRT) is a mobile electron accelerator designed to irradiate small areas of tissue, up to 10 cm in diameter, with electron beams during surgical procedures. It is characterized by a great mobility guaranteed by a number of degrees of freedom enabling irradiation in the conditions of an operating theatre.
Rep Pract Oncol Radiother
February 2018
Aim: To investigate the influence of several factors on the accuracy of dose measurements and feasibility of application of small Gafchromic detectors for postal audit.
Background: Our experience showed that precision of dose measurements with small pieces of Gafchromic films may be significantly improved.
Materials And Methods: Gafchromic films with dimensions of 1 × 1, 2 × 2 and 3 × 3 cm were exposed to 6 MV X-rays at dose levels of 50 cGy-210 cGy.
The aim of this study was to propose a method to predict the minimum achievable mean lung dose (MLD) and corresponding dosimetric parameters for organs-at-risk (OAR) based on individual patient anatomy. For each patient, the dose for 36 equidistant individual multileaf collimator shaped fields in the treatment planning system (TPS) was calculated. Based on these dose matrices, the MLD for each patient was predicted by the homemade DosePredictor software in which the solution of linear equations was implemented.
View Article and Find Full Text PDFAim: The goal of this prospective study was to assess the effectiveness of a hypofractionated accelerated regime in treatment of the larynx cancer.
Background: Multiple radiotherapy delivery regimes are used for treatment of the larynx cancer. Hypofractionated regimes could provide similar results with reduced use of radiotherapy facilities.
This paper presents the situation of the profession of medical physicists in Poland. The official recognition of the profession of medical physicist in Polish legislation was in 2002. In recent years, more and more Universities which have Physics Faculties introduce a medical physics specialty.
View Article and Find Full Text PDFRep Pract Oncol Radiother
June 2015
Aim: In this study we compared three different methods of evaluation of dose distribution.
Background: The aim of treatment planning is to prepare the treatment plan which the criteria are defined according to the international recommendations.
Materials And Methods: For three groups of patients, for lung, breast and prostate, treated radically in Brzozow with external beams the treatment plans were prepared.
Rep Pract Oncol Radiother
May 2015
Background: Late rectal injury is a common side effect of external beam radiotherapy for prostate cancer.
Aim: The aim of this study was to evaluate what total dose may be safely delivered for prostate patients for 3DCRT and IMRT techniques and the CTV-PTV margin.
Materials And Methods: 3DCRT and IMRT plans were prepared for 12 patients.
Rep Pract Oncol Radiother
May 2015
Aim: To verify the reproducibility of patients irradiated after mastectomy on the immobilization system designed and manufactured for our hospital and to compare the Internal Protocol (IP) with the modified-No Action Level Protocol.
Background: Application of forward IMRT techniques requires a good reproducibility of patient positioning. To minimize the set-up error, an effective immobilization system is important.
Rep Pract Oncol Radiother
November 2014
Aim: The aim of this work is to present a method of beam weight and wedge angle optimization for patients with prostate cancer.
Background: 3D-CRT is usually realized with forward planning based on a trial and error method. Several authors have published a few methods of beam weight optimization applicable to the 3D-CRT.
Rep Pract Oncol Radiother
May 2014
Aim: In this work we test the usage of dose gradient based algorithm for the selection of beam weights in 3D-CRT plans for different cancer locations. Our algorithm is easy to implement for three fields technique with wedges defined by planner.
Background: 3D-CRT is usually realized with forward planning which is quite time consuming.
Rep Pract Oncol Radiother
January 2014
Aim: To validate a pretreatment verification method of dose calculation and dose delivery based on measurements with Metaplex PTW phantom.
Background: The dose-response relationships for local tumor control and radiosensitive tissue complications are strong. It is widely accepted that an accuracy of dose delivery of about 3.
Purpose: There is a need to develop predictive tests that would allow identifying cancer patients with a high risk of developing side effects to radiotherapy. We compared the predictive value of three functional assays: the G(0) aberration assay, the G(2) aberration assay and the alkaline comet assay in lymphocytes of breast cancer and gynaecological cancer patients.
Material And Methods: Peripheral blood was collected from 35 patients with breast cancer and 34 patients with gynaecological cancer before the onset of therapy.