3,691 results match your criteria dose homogeneity


Is Hypoxia a Factor Influencing PSMA-Directed Radioligand Therapy?-An In Silico Study on the Role of Chronic Hypoxia in Prostate Cancer.

Cancers (Basel) 2021 Jul 8;13(14). Epub 2021 Jul 8.

Department of Nuclear Medicine, Inselspital, University of Bern, 3010 Bern, Switzerland.

Radioligand therapy (RLT) targeting prostate specific-membrane antigen (PSMA) is an emerging treatment for metastatic castration-resistant prostate cancer (mCRPC). It administrates 225Ac- or 177Lu-labeled ligands for the targeted killing of tumor cells. Differently from X- or γ-ray, for the emitted α or β particles the ionization of the DNA molecule is less dependent on the tissue oxygenation status. Read More

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Dosimetric comparison of MR-linac-based IMRT and conventional VMAT treatment plans for prostate cancer.

Radiat Oncol 2021 Jul 21;16(1):133. Epub 2021 Jul 21.

Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.

Background: The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Read More

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Dosimetric Comparison of Whole Breast Radiotherapy Using Field-in-Field and Volumetric Modulated Arc Therapy Techniques in Left-Sided Breast Cancer Patients.

Cureus 2021 Jun 18;13(6):e15732. Epub 2021 Jun 18.

Department of Clinical and Radiation Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, PAK.

Introduction The radiotherapy of left-sided breast cancers is challenging because of neighboring critical organs, posing an increased risk of complications. Various radiation delivery techniques have been used to deliver the desired dose of radiation to the target area while keeping the doses to nearby structures within constraints. The main aim of this study is to quantify doses delivered to the organs at risk (OARs) including heart, left lung, spinal cord, and contralateral breast, and to the planning target volume (PTV) using Field-in-Field (FIF) and Volumetric Modulated Arc Therapy (VMAT). Read More

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Comparison of 2 dynamic conformal arc plans based on high-dose rate flattening filter free beams for peripheral lung cancer.

Zhong Nan Da Xue Xue Bao Yi Xue Ban 2021 Jun;46(6):615-619

Department of Radiation Therapy, Cancer Hospital of Shantou University Medical College, Shantou Guangdong 515000, China.

Objectives: To compare 2 dynamic conformal arc plans based on the high dose rate flattening filter free (FFF) beams, and to evaluate the dosimetric differences.

Methods: A total of 20 patients with early peripheral non-small cell lung cancer were selected, and 2 dynamic conformal arc plans were designed in the Eclipse 10.0 treatment planning system (TPS). Read More

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How to stop disproportionation of a hydrochloride salt of a very weakly basic compound in a non-clinical suspension formulation.

Int J Pharm 2021 Jul 14:120875. Epub 2021 Jul 14.

Division of Pharmaceutical Chemistry and Technology, Industrial Pharmacy, University of Helsinki, P.O. Box 56, 00014 University of Helsinki, Finland.

Our objectives were to stabilize a non-clinical suspension for use in toxicological studies and to develop methods to investigate the stability of the formulation in terms of salt disproportionation. The compound under research was a hydrochloride salt of a practically insoluble discovery compound ODM-203. The first of the three formulation approaches was a suspension prepared and stored at room temperature. Read More

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Dosimetric Comparison of Robotic and Linear Accelerator Multi-Leaf Collimator-Based Stereotactic Radiosurgery for Arteriovenous Malformation.

J Med Phys 2021 Jan-Mar;46(1):16-25. Epub 2021 May 5.

Division of Radiation Oncology, Medanta Cancer Institute, Medanta The Medicity, Gurgaon, Haryana, India.

Purpose: To investigate the dosimetric comparison of different collimators which are used in robotic radiosurgery (cyberknife-CK) and linear accelerator (LINAC) for stereotactic radiosurgery (SRS) in arteriovenous malformation (AVM).

Materials And Methods: Twenty-five AVM patients were planned in CK using FIXED cone, IRIS collimator, and multi-leaf collimator (MLC) based in LINAC. Dosimetric comparison was performed using Paddick conformity index (CI) and International Commission on Radiation Units and measurements (ICRU) homogeneity index (HI), gradient score (GS), normal brain dose received by 10cc (D) and critical structure (brain stem, optic chiasma, optic nerves) doses. Read More

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A rapid review of influential factors and appraised solutions on organ delineation uncertainties reduction in radiotherapy.

Biomed Phys Eng Express 2021 Jul 29;7(5). Epub 2021 Jul 29.

Radiotherapy Oncology Department, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.

Accurate volume delineation plays an essential role in radiotherapy. Contouring is a potential source of uncertainties in radiotherapy treatment planning that could affect treatment outcomes. Therefore, reducing the degree of contouring uncertainties is crucial. Read More

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Evaluation of Three-Dimensional Conformal Radiotherapy and Intensity Modulated Radiotherapy Techniques for Left Breast Post-Mastectomy Patients: Our Experience in Nigerian Sovereign Investment Authority-Lagos University Teaching Hospital Cancer Center, South-West Nigeria.

Eur J Breast Health 2021 Jul 24;17(3):247-252. Epub 2021 Jun 24.

Department of Radiation Biology, Division of Radiotherapy and Radiodiagnosis, College of Medicine, University of Lagos/NSIA-LUTH Cancer Centre, Lagos, Nigeria.

Objective: This study aimed to evaluate the dosimetric properties of treatment plans obtained from three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy techniques (IMRT) plans for left chest wall breast cancer patients.

Materials And Methods: A total of 20 patients with left-sided chest wall radiotherapy were randomly selected with the dose prescriptions: 42 Gy and 45 Gy in 15 and 18 fractions, respectively. Treatment plans were obtained using 3D-CRT and IMRT for each patient. Read More

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CT radiomic features of photodynamic priming in clinical pancreatic adenocarcinoma treatment.

Phys Med Biol 2021 Jul 14. Epub 2021 Jul 14.

Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, UNITED STATES.

Photodynamic therapy (PDT) offers localized focal ablation in unresectable pancreatic tumors while tissues surrounding the treatment volume experience a lower light dose, termed photodynamic priming (PDP). While PDP does not cause tissue damage, it has been demonstrated to promote vascular permeability, improve drug delivery, alleviate tumor cell density, and reduce desmoplasia and the resultant internal pressure in pre-clinical evaluation. Preclinical data supports PDP as a neoadjuvant therapy beneficial to subsequent chemotherapy or immunotherapy, yet it is challenging to quantify PDP effects in clinical treatment without additional imaging and testing. Read More

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Clinical Implementation of Automated Treatment Planning for Rectum Intensity-Modulated Radiotherapy Using Voxel-Based Dose Prediction and Post-Optimization Strategies.

Front Oncol 2021 24;11:697995. Epub 2021 Jun 24.

Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.

Purpose: This study aims to demonstrate the feasibility of clinical implementation of automated treatment planning (ATP) using voxel-based dose prediction and post-optimization strategies for rectal cancer on uRT (United Imaging Healthcare, Shanghai, China) treatment planning system.

Methods: A total of 180 previously treated rectal cancer cases were enrolled in this study, including 160 cases for training, 10 for validation and 10 for testing. Using CT image data, planning target volumes (PTVs) and contour delineation of the organs at risk (OARs) as input and three-dimensional (3D) dose distribution as output, a 3D-Uet DL model was developed. Read More

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An atlas-guided automatic planning approach for rectal cancer intensity-modulated radiotherapy.

Phys Med Biol 2021 Jul 23;66(15). Epub 2021 Jul 23.

Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, People's Republic of China.

We try to develop an atlas-guided automatic planning (AGAP) approach and evaluate its feasibility and performance in rectal cancer intensity-modulated radiotherapy. The developed AGAP approach consisted of four independent modules: patient atlas, similar patient retrieval, beam morphing (BM), and plan fine-tuning (PFT) modules. The atlas was setup using anatomy and plan data from Pinnacle auto-planning (P-auto) plans. Read More

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Safety, Efficacy, and Cost of 0.4-mg Versus 2-mg Intranasal Naloxone for Treatment of Prehospital Opioid Overdose.

Ann Pharmacother 2021 Jul 6:10600280211030918. Epub 2021 Jul 6.

University of Michigan, Ann Arbor, MI, USA.

Background: Intranasal naloxone is commonly used to treat prehospital opioid overdose. However, the optimal dose is unclear, and currently, no study exists comparing the clinical effect of intranasal naloxone at different doses.

Objective: The goal of this investigation was to compare the safety, efficacy, and cost of 0. Read More

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A three-dimensional printed customized bolus: adapting to the shape of the outer ear.

Rep Pract Oncol Radiother 2021 14;26(2):211-217. Epub 2021 Apr 14.

Department of Radiation Oncology, University Hospital Virgen del Rocio, Seville, Spain.

Background: The skin-sparing effect of megavoltage-photon beams in radiotherapy (RT) reduces the target coverage of superficial tumours. Consequently, a bolus is widely used to enhance the target coverage for superficial targets. This study evaluates a three-dimensional (3D)-printed customized bolus for a very irregular surface, the outer ear. Read More

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Improved Ipsilateral Breast and Chest Wall Sparing With MR-Guided 3-fraction Accelerated Partial Breast Irradiation: A Dosimetric Study Comparing MR-Linac and CT-Linac Plans.

Adv Radiat Oncol 2021 May-Jun;6(3):100654. Epub 2021 Jan 22.

Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.

Purpose: External beam accelerated partial breast irradiation (APBI) is subject to treatment uncertainties that must be accounted for through planning target volume (PTV) margin. We hypothesize that magnetic resonance-guided radiation therapy with reduced PTV margins enabled by real-time cine magnetic resonance image (MRI) target monitoring results in better normal tissue sparing compared with computed tomography (CT)-guided radiation therapy with commonly used clinical PTV margins. In this study, we compare the plan quality of ViewRay MRIdian Linac forward planned intensity modulated radiation therapy and TrueBeam volumetric modulated arc therapy for a novel 3-fraction APBI schedule. Read More

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January 2021

Analysis of Geometric and Dosimetric Effects of Bra Application to Support Large or Pendulous Breasts During Radiotherapy Planning: A Retrospective Single-Center Study.

Technol Cancer Res Treat 2021 Jan-Dec;20:15330338211027909

Department of Radiation Oncology, Jeju National University Hospital, Jeju University College of Medicine, Jeju, South Korea.

Purpose: To evaluate geometric and dosimetric effects of bra application during radiotherapy planning for breast cancer patients with large and pendulous breasts.

Materials And Methods: Twenty patients with chest sizes >38 inches between April 2019 and July 2019 underwent radiotherapy planning with and without a radiation bra (Chabner XRT). Geometric and dosimetric parameters included the breast volume, superior-inferior (SI) distance, separation (S) as the distance of the longest diameter of the clinical target volume (CTV), conformity number (CN), and homogeneity index (HI) of CTV. Read More

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Technical Note: Multiple energy extraction techniques for synchrotron-based proton delivery systems may exacerbate motion interplay effects in lung cancer treatments.

Med Phys 2021 Jun 26. Epub 2021 Jun 26.

Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, USA.

Purpose: The multiple energy extraction (MEE) delivery technique for synchrotron-based proton delivery systems reduces beam delivery time by decelerating the beam multiple times during one accelerator spill, but this might cause additional plan quality degradation due to intrafractional motion. We seek to determine whether MEE causes significantly different plan quality degradation compared to single energy extraction (SEE) for lung cancer treatments due to the interplay effect.

Methods: Ten lung cancer patients treated with IMPT at our institution were nonrandomly sampled based on a representative range of tumor motion amplitudes, tumor volumes, and respiratory periods. Read More

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Interstitial multi-catheter breast brachytherapy: Technical aspects and experience feedback in a comprehensive cancer center.

Cancer Radiother 2021 Jun 16. Epub 2021 Jun 16.

Department of radiotherapy, institut de cancérologie de Lorraine, 54519 Vandœuvre-lès-Nancy, France.

Purpose: To focus on technical aspects of the implementation of interstitial high dose rate brachytherapy, with a step-by-step approach.

Materials And Methods: Patients were selected during multidisciplinary tumor boards, according to inclusion criteria adapted from GEC-ESTRO guidelines. A CT scan was performed a few days before implantation. Read More

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Motion management with variable cycle-based respiratory guidance method for carbon-ion pencil beam scanning treatment.

Authors:
Pengbo He Qiang Li

Phys Med 2021 Jul 13;87:99-105. Epub 2021 Jun 13.

Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:

Purpose: A novel variable cycle-based respiratory guidance method was proposed to synchronize the patterns between patients' breathing and the magnetic excitation of synchrotron under the mode of full-energy depth scanning beam delivery, in order to improve the treatment precision and efficiency for carbon ion therapy.

Methods: Audio-visual biofeedback system with variable cycle-based respiratory guidance method was developed. We enrolled 6 healthy volunteers and a simulation study of the fixed cycle-based and variable cycle-based respiratory guidance with three treatment fractions was performed. Read More

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Dosimetric impact of dwell time deviation constraint on inverse brachytherapy treatment planning and comparison with conventional optimization method for interstitial brachytherapy implants.

J Cancer Res Ther 2021 Apr-Jun;17(2):463-470

Department of Radiotherapy, Lok Nayak Hospital, Delhi, India.

Purpose: High-dose rate remote afterloading brachytherapy machine and advanced treatment planning system help in getting optimum dose to tumor and low dose to normal structures. Inverse planning simulated annealing (IPSA) optimization technique has a unique feature of dwell time deviation constraint (DTDC). In this study, six IPSA-based plans having different DTDC values with routinely practiced geometric plus graphical optimization (GO + GrO) have been compared using various dosimetric parameters. Read More

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Radiotherapy plan evaluation indices: A dosimetrical suitability check.

J Cancer Res Ther 2021 Apr-Jun;17(2):455-462

Department of Radiation Oncology, RMLIMS, Lucknow, Uttar Pradesh, India.

Purpose: To classify the available plan evaluation indices and compare the dosimetric suitability of these indices.

Materials And Methods: Available published plan evaluation indices were categorized. Conformity index (CI) into two groups, one group contains those CI formulas which do not consider critical structure and other group contains those CI formulas which consider planning target volume (PTV) coverage, normal tissue and critical structure sparing simultaneously. Read More

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Evaluation of fully automated a priori MCO treatment planning in VMAT for head-and-neck cancer.

Phys Med 2021 Jul 8;87:31-38. Epub 2021 Jun 8.

Centre Léon Bérard, 28 rue Laennec 69373, LYON Cedex 08, France.

Purpose: Automated planning techniques aim to reduce manual planning time and inter-operator variability without compromising the plan quality which is particularly challenging for head-and-neck (HN) cancer radiotherapy. The objective of this study was to evaluate the performance of an a priori-multicriteria plan optimization algorithm on a cohort of HN patients.

Methods: A total of 14 nasopharyngeal carcinoma (upper-HN) and 14 "middle-lower indications" (lower-HN) previously treated in our institution were enrolled in this study. Read More

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Impact of errors in spot size and spot position in robustly optimized pencil beam scanning proton-based stereotactic body radiation therapy (SBRT) lung plans.

J Appl Clin Med Phys 2021 Jul 7;22(7):147-154. Epub 2021 Jun 7.

Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.

Purpose: The purpose of the current study was threefold: (a) investigate the impact of the variations (errors) in spot sizes in robustly optimized pencil beam scanning (PBS) proton-based stereotactic body radiation therapy (SBRT) lung plans, (b) evaluate the impact of spot sizes and position errors simultaneously, and (c) assess the overall effect of spot size and position errors occurring simultaneously in conjunction with either setup or range errors.

Methods: In this retrospective study, computed tomography (CT) data set of five lung patients was selected. Treatment plans were regenerated for a total dose of 5000 cGy(RBE) in 5 fractions using a single-field optimization (SFO) technique. Read More

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Clinical verification of treatment planning dose calculation in lung SBRT with GATE Monte Carlo simulation code.

Phys Med 2021 Jul 3;87:1-10. Epub 2021 Jun 3.

Instituto de Fı́sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address:

Purpose: This study aims to use GATE/Geant4 simulation code to evaluate the performance of dose calculations with Anisotropic Analytical Algorithm (AAA) in the context of lung SBRT for complex treatments considering images of patients.

Methods: Four cases of non-small cell lung cancer treated with SBRT were selected for this study. Irradiation plans were created with AAA and recalculated end to end using Monte Carlo (MC) method maintaining field configurations identical to the original plans. Read More

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Dose optimization comparison study of inverse planning simulated annealing [IPSA] and hybrid inverse planning optimization [HIPO] in interstitial brachytherapy of head and neck cancer.

J Med Imaging Radiat Sci 2021 Jun 1. Epub 2021 Jun 1.

Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, PIN-221005, India. Electronic address:

Purpose: This study was a retrospective dose optimization comparison of two commercially available inverse planning algorithms, the inverse planning simulated annealing (IPSA) and hybrid inverse planning optimization (HIPO) for head and neck cancer interstitial brachytherapy.

Materials And Methods: Seven patients with head and neck cancer were selected (4 with tongue cancer, 2 with buccal mucosa cancer and 1 with carcinoma lip) who were previously treated with interstitial brachytherapy using a flexible nylon tube catheter and graphical optimization/geometric optimization technique. All seven patients were retrospectively re-planned using both IPSA as well as HIPO algorithms available in the Oncentra Brachytherapy Treatment Planning System (TPS) version V4. Read More

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Field-in-Field Technique With Intrafractionally Modulated Junction Shifts for Craniospinal Irradiation Planning With Three-Dimensional Conformal Radiation Therapy.

Cureus 2021 Apr 28;13(4):e14744. Epub 2021 Apr 28.

Oncology, Ziauddin University, Karachi, PAK.

Background: Planning craniospinal irradiation (CSI) with ''field-in-field'' (FIF) homogenization technique in combination with daily, intrafractional modulation of the field junctions is needed to avoid spinal cord overdose. Photon-based techniques for CSI may result in dose inhomogeneity within the treatment volume and usually require a weekly manual shift of the field junctions to minimize the possibility of spinal cord overdose. Nowadays, FIF technique is used to feather out the dose inhomogeneity caused by multiple fields. Read More

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A Dry Powder Platform for Nose-to-Brain Delivery of Dexamethasone: Formulation Development and Nasal Deposition Studies.

Pharmaceutics 2021 May 26;13(6). Epub 2021 May 26.

Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia.

Nasal route of administration offers a unique opportunity of brain targeted drug delivery via olfactory and trigeminal pathway, providing effective CNS concentrations at lower doses and lower risk for adverse reactions compared to systemic drug administration. Therefore, it has been recently proposed as a route of choice for glucocorticoids to control neuroinflammation processes in patients with severe Covid-19. However, appropriate delivery systems tailored to enhance their efficacy yet need to emerge. Read More

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Gonadal-sparing total body irradiation with the use of helical tomotherapy for nonmalignant indications.

Rep Pract Oncol Radiother 2021 25;26(1):153-158. Epub 2021 Feb 25.

Department of Radiation Oncology, H. Lee Moffit Cancer Center and Research Institute, Tampa, FL, United States.

Background: The aim was to demonstrate the feasibility and technique of gonadal sparing total body irradiation (TBI) with helical tomotherapy. Total body irradiation is a common part of the conditioning regimen prior to allogeneic stem cell transplantation. Shielding or dose-reduction to the gonads is often desired to preserve fertility, particularly in young patients undergoing transplant for non-malignant indications. Read More

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February 2021

Noncoplanar Versus Coplanar Intensity-Modulated Radiation Therapy (IMRT) for Protection of the Lip and Buccal Mucosa.

Technol Cancer Res Treat 2021 Jan-Dec;20:15330338211019511

Department of Oral Maxillofacial Head and Neck Oncology, 56695Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, Shanghai China.

Objective: In this study, by comparing coplanar and noncoplanar intensity-modulated radiation therapy (IMRT) treatment planning in treating tongue cancer, the significance of noncoplanar fields in the protection of the lip and buccal mucosa was determined, and a reasonable solution was selected.

Methods: Forty-eight tongue cancer patients treated from June 2019 to February 2021 were selected and randomly divided into a coplanar field group and a noncoplanar field group. The mucosal dose limit changed from 15 Gy to 45 Gy for comparison of the two treatment plans. Read More

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Dosimetric comparison between different tangential field arrangements during left-sided breast cancer radiotherapy.

Radiol Phys Technol 2021 May 27. Epub 2021 May 27.

Radiation Oncology Department, Sabzevar University of Medical Sciences, Sabzevar, Iran.

This study aimed to evaluate variations in dose distribution within the target volume and dose received by the organs at risk (OARs) for different tangential field arrangements during three-dimensional (3D) conformal treatment planning for left-sided breast cancer. Computed tomography (CT) images of 25 breast cancer patients were included, and three different mono-isocentric half-block (MIHB) treatment plans-parallel central axis technique (PCAXT), posterior border parallel technique (PBPT), and parallel quadrant technique (PQUDT)-were considered for each patient. The dosimetric and geometric parameters related to each followed plan were then extracted for the planning target volume (PTV) and the OARs, and compared. Read More

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An audit of high dose-rate prostate brachytherapy treatment planning at six Swedish clinics.

J Contemp Brachytherapy 2021 Feb 18;13(1):59-71. Epub 2021 Feb 18.

Medical Radiation Physics, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.

Purpose: High dose-rate prostate brachytherapy has been implemented in Sweden in the late 1980s and early 1990s in six clinics using the same schedule: 20 Gy in two fractions combined with 50 Gy in 25 fractions with external beam radiation therapy. Thirty years have passed and during these years, various aspects of the treatment process have developed, such as ultrasound-guided imaging and treatment planning system. An audit was conducted, including a questionnaire and treatment planning, which aimed to gather knowledge about treatment planning methods in Swedish clinics. Read More

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February 2021