Login to your account
Don’t have an account?
Create a Free AccountDirected Journal Readings (DJR)
Risk factors for radiotherapy incidents: a single institutional experience
We aimed to analyze risk factors for incidents occurring during the practice of external beam radiotherapy (EBRT) at a single Japanese center. Treatment data for EBRT from June 2014 to March 2017 were collected. Data from incident reports submitted during this period were reviewed. Near-miss cases were not included. Risk factors for incidents, including patient characteristics and treatment-related factors, were explored using uni- and multivariate analyses. Factors contributing to each incident were also retrospectively categorized according to the recommendations of the American Association of Physicists in Medicine (AAPM).Immobilization and image-guidance methods for radiation therapy of limb extremity soft tissue sarcomas: Results of a multi-institutional survey
Radiation therapy for limb-extremity soft tissue sarcoma (STS) requires accurate, reproducible dose delivery. However, patient positioning is challenging and there is a lack of existing guidelines to assist institutional standardization. Therefore, we conducted a multi-institutional international survey of STS immobilization, image guidance methods, and treatment protocols to investigate current practice. Seventy-three UK radiotherapy centers and 15 hospitals in 7 other countries completed a questionnaire on STS immobilization and image-guidance procedures.Fine-tuning the normal tissue objective in eclipse for lung stereotactic body radiation therapy
The purpose of this study was to characterize the effects of the normal tissue objective (NTO) on lung stereotactic body radiation therapy (SBRT) dose distributions. The NTO is a spatially varying constraint used in Eclipse to limit dose to normal tissues by steepening the dose gradient. However, the multitude of potential NTO setting combinations challenges optimal NTO tuning. In the present study, a broad range of NTO settings are investigated for lung SBRT treatment planning with volumetric modulated arc therapy(VMAT).Knowledge-based treatment planning and its potential role in the transition between treatment planning systems
Commissioning a new treatment planning system (TPS) involves many time-consuming tasks. We investigated the role that knowledge-based planning (KBP) can play in aiding a clinic's transition to a new TPS. Sixty clinically treated prostate/prostate bed intensity-modulated radiation therapy (IMRT) plans were exported from an in-house TPS and were used to create a KBP model in a newly implemented commercial application. To determine the benefit that KBP may have in a TPS transition, the model was tested on 2 groups of patients.Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm
For left-sided postmastectomy patients requiring chest wall plus comprehensive nodal irradiation, sometimes traditional techniques such as partial wide tangents or electron/tangents combination are not feasible due to abnormal chest wall contour or heart position or unusually wide excision scar. We developed electron chest wall irradiation technique using Electron Monte Carlo (EMC) dose algorithm that will achieve heart sparing with acceptable ipsilateral lung dose, minimal contralateral lung, and breast dose.Radiation therapy of synchronous bilateral breast carcinoma (SBBC) using multiple techniques
The purpose of this study was to establish intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans for synchronous bilateral breast cancer (SBBC) and to compare those plans with the previous treatment plans using 3D conformal radiation therapy (3DCRT). The differences among the treatments were also statistically compared regarding dosimetry distribution and treatment efficiency. The research was conducted with 10 SBBC patients. The study established IMRT (12 fields with a single isocenter) and VMAT (2 partial arcs with a single isocenter) treatment plans for SBBC patients and then compared those plans with 3DCRT (8 fields with multiple isocenters).Improving plan quality for prostate volumetric-modulated arc therapy
We critically evaluated the quality and consistency of volumetric-modulated arc therapy (VMAT) prostate planning at a single institution to quantify objective measures for plan quality and establish clear guidelines for plan evaluation and quality assurance. A retrospective analysis was conducted on 34 plans generated on the Pinnacle3 version 9.4 and 9.8 treatment planning system to deliver 78 Gy in 39 fractions to the prostate only using VMAT. Data were collected on contoured structure volumes, overlaps and expansions, planning target volume (PTV) and organs at risk volumes and relationship, dose volume histogram, plan conformity, plan homogeneity, low-dose wash, and beam parameters.Whole breast nodal irradiation using supine VMAT and prone 3D planning: A case study
The purpose of this study was to compare the variations in doses to the ipsilateral lung and heart between the supine whole breast and nodal volumetric-modulated arc therapy (VMAT) technique and the prone 3-dimensional conformal radiation therapy (3DCRT) technique. In this study, 3 patients who were simulated in the prone and supine positions were planned using supine VMAT and prone 3DCRT techniques to compare planning target volume (PTV) coverage as well as dose to organs at risk (ORs), including the heart and ipsilateral lung.Radiation-induced hypothyroidism in patients with breast cancer: a retrospective analysis of 243 cases
This study aims to estimate the incidence of hypothyroidism (HT) and to evaluate the predictors affecting the development of HT after radiotherapy (RT) for breast cancer, with a focus on radiation dose-volumetric parameters. Between 2009 and 2015, 243 patients undergoing RT for breast cancer were retrospectively analyzed. Free triiodothyronine (FT3), free thyroxin (FT4), and thyrotropin (TSH) were monitored before and after RT. The relation between the doses to thyroid gland (Dmean, Dmax, Dmin), percentage of thyroid volume receiving > 10 Gy, 20 Gy, 30 Gy, 40 Gy, and 50 Gy (V10 to V50), absolute thyroid volume, and HT were analyzed.Impact of intravenous contrast used in computed tomography on radiation dose to carotid arteries and thyroid in intensity-modulated radiation therapy planning for nasopharyngeal carcinoma
The aim of this study was to investigate if intravenous contrast injection affected the radiation doses to carotid arteries and thyroid during intensity-modulated radiation therapy (IMRT) planning for nasopharyngeal carcinoma (NPC). Thirty consecutive patients with NPC underwent plain computed tomography (CT) followed by repeated scanning after contrast injection. Carotid arteries (common, external, internal), thyroid, target volumes, and other organs-at-risk (OARs), as well as IMRT planning, were based on contrast-enhanced CT (CE-CT) images.The dilemma of parotid gland and pharyngeal constrictor muscles preservation—Is daily online image guidance required? A dosimetric analysis
With margin reduction common in head and neck radiotherapy, it is critical that the dosimetric effects of setup deviations are quantified. With past studies focusing on the quantification of positional and volumetric changes of organs at risk (OARs), this study aimed to measure the dose delivered to these the parotid gland (PG) and pharyngeal constrictor muscles (PCMs) using cone beam computed tomography (CBCT). Furthermore, this investigation sought to establish a potential time trend of change in dose delivered to target volumes secondary to ascertaining the need for daily image guidance (IG) to reduce the dose burden to these important OARs.Dosimetric effect of beam arrangement for intensity-modulated radiation therapy in the treatment of upper thoracic esophageal carcinoma
To evaluate the lung sparing in intensity-modulated radiation therapy (IMRT) for patients with upper thoracic esophageal tumors extending inferiorly to the thorax by different beam arrangement. Overall, 15 patient cases with cancer of upper thoracic esophagus were selected for a retrospective treatment-planning study. Intensity-modulated radiation therapy plans using 4, 5, and 7 beams (4B, 5B, and 7B) were developed for each patient by direct machine parameter optimization (DMPO). All plans were evaluated with respect to dose volumes to irradiated targets and normal structures, with statistical comparisons made between 4B with 5B and 7B intensity-modulated radiation therapy plans.Risks of secondary malignancies with heterotopic bone radiation therapy for patients younger than 40 years
Heterotopic ossification (HO) of the bone is defined as a benign condition in which abnormal bone formation occurs in soft tissue. One of the most common prophylactic treatments for HO is radiation therapy (RT). This study retrospectively reviewed 20 patients younger than the age of 40 who received radiation to prevent HO in a single fraction of 7 Gray. The purpose of this study is to assess the risk of a second malignancy in these patients by recreating their treatment fields and contouring organs at risk to estimate the radiation dose absorbed by normal tissues outside the radiation treatment field.Analysis of nodal coverage utilizing image guided radiation therapy for primary gynecologic tumor volumes
To evaluate radiation dose delivered to pelvic lymph nodes, if daily Image Guided Radiation Therapy (IGRT) was implemented with treatment shifts based on the primary site (primary clinical target volume [CTV]). Our secondary goal was to compare dosimetric coverage with patient outcomes.Dosimetric evaluation of 4 different treatment modalities for curative-intent stereotactic body radiation therapy for isolated thoracic spinal metastases
To investigate the dosimetric characteristics of 4 SBRT-capable dose delivery systems, CyberKnife (CK), Helical TomoTherapy (HT), Volumetric Modulated Arc Therapy (VMAT) by Varian RapidArc (RA), and segmental step-and-shoot intensity-modulated radiation therapy (IMRT) by Elekta, on isolated thoracic spinal lesions. CK, HT, RA, and IMRT planning were performed simultaneously for 10 randomly selected patients with 6 body types and 6 body + pedicle types with isolated thoracic lesions. The prescription was set with curative intent and dose of either 33 Gy in 3 fractions (3F) or 40 Gy in 5F to cover at least 90% of the planning target volume (PTV), correspondingly.Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients
The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT.Residual position errors of lymph node surrogates in breast cancer adjuvant radiotherapy: Comparison of two arm fixation devices and the effect of arm position correction
Residual position errors of the lymph node (LN) surrogates and humeral head (HH) were determined for 2 different arm fixation devices in radiotherapy (RT) of breast cancer: a standard wrist-hold (WH) and a house-made rod-hold (RH). The effect of arm position correction (APC) based on setup images was also investigated. A total of 113 consecutive patients with early-stage breast cancer with LN irradiation were retrospectively analyzed (53 and 60 using the WH and RH, respectively). Residual position errors of the LN surrogates (Th1-2 and clavicle) and the HH were investigated to compare the 2 fixation devices.Dosimetric comparison of hybrid volumetric-modulated arc therapy, volumetric-modulated arc therapy, and intensity-modulated radiation therapy for left-sided early breast cancer
To compare the dosimetric performance of 3 different treatment techniques: hybrid volumetric-modulated arc therapy (hybrid-VMAT), pure-VMAT, and fixed-field intensity-modulated radiation therapy (F-IMRT) for whole-breast irradiation of left-sided early breast cancer. The hybrid-VMAT treatment technique and 2 other treatment techniques—pure-VMAT and F-IMRT—were compared retrospectively in 10 patients with left-sided early breast cancer. The treatment plans of these patients were replanned using the same contours based on the original computed tomography (CT) data sets.A planning comparison of 3-dimensional conformal multiple static field, conformal arc, and volumetric modulated arc therapy for the delivery of stereotactic body radiotherapy for early stage lung cancer
The primary objective of this study was to compare dosimetric variables as well as treatment times of multiple static fields (MSFs), conformal arcs (CAs), and volumetric modulated arc therapy (VMAT) techniques for the treatment of early stage lung cancer using stereotactic body radiotherapy (SBRT). Treatments of 23 patients previously treated with MSF of 48 Gy to 95% of the planning target volume (PTV) in 4 fractions were replanned using CA and VMAT techniques. Dosimetric parameters of the Radiation Therapy Oncology Group (RTOG) 0915 trial were evaluated, along with the van׳t Riet conformation number (CN), monitor units (MUs), and actual and calculated treatment times.Technique for comprehensive head and neck irradiation using 3-dimensional conformal proton therapy
Owing to the technical and logistical complexities of matching photon and proton treatment modalities, we developed and implemented a technique of comprehensive head and neck radiation using 3-dimensional (3D) conformal proton therapy. A monoisocentric technique was used with a 30-cm snout. Cervical lymphatics were treated with 3 fields: a posterior-anterior field with a midline block and a right and a left posterior oblique field. The matchline of the 3 cervical nodal fields with the primary tumor site fields was staggered by 0.5 cm.Comparison of doses received by the hippocampus in patients treated with single isocenter– vs multiple isocenter–based stereotactic radiation therapy to the brain for multiple brain metastases
To investigate the doses received by the hippocampus and normal brain tissue during a course of stereotactic radiation therapy using a single isocenter (SI)–based or multiple isocenter (MI)–based treatment planning in patients with less than 4 brain metastases. In total, 10 patients with magnetic resonance imaging (MRI) demonstrating 2-3 brain metastases were included in this retrospective study, and 2 sets of stereotactic intensity-modulated radiation therapy (IMRT) treatment plans (SI vs MI) were generated.Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose
Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50 Gy over 25 fractions was prescribed.Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff
We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R50%); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D2cm) to follow Radiation Therapy Oncology Group (RTOG) 0915.Radiobiologic comparison of helical tomotherapy, intensity modulated radiotherapy, and conformal radiotherapy in treating lung cancer accounting for secondary malignancy risks
The aim of the present study is to examine the importance of using measures to predict the risk of inducing secondary malignancies in association with the clinical effectiveness of treatment plans in terms of tumor control and normal tissue complication probabilities. This is achieved by using radiobiologic parameters and measures, which may provide a closer association between clinical outcome and treatment delivery. Overall, 4 patients having been treated for lung cancer were examined. For each of them, 3 treatment plans were developed based on the helical tomotherapy (HT), multileaf collimator-based intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (CRT) modalities.A fixed-jaw method to protect critical organs during intensity-modulated radiotherapy
Intensity-modulated radiotherapy (IMRT) plays an important role in cancer radiotherapy. For some patients being treated with IMRT, the extremely low tolerances of critical organs (such as lens, ovaries, and testicles) cannot be met during treatment planning. The aim of this article is to introduce a new planning method to overcome that problem. In current planning practice, jaw positions are automatically set to cover all target volumes by the planning system (e.g., Pinnacle3 system). Because of such settings, critical organs may be fully blocked by the multileaf collimator (MLC), but they still sit in the field that is shaped by collimator jaws.
