A hypofractionation treatment protocol for prostate cancer was initiated in our department in December 2003. The treatment regimen consists of a total dose of 36.25 Gy delivered at 7.25 Gy per fraction over 10 days. We discuss the rationale for such a prostate hypofractionation protocol and the need for frequent prostate imaging during treatment. The ...

Purpose: To evaluate the toxicity of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- to high-risk prostate cancer. Methods and Materials: A retrospective toxicity analysis was performed in 30 consecutive patients treated definitively with pelvic ...

Purpose: To evaluate the acute toxicities of hypofractionated accelerated radiotherapy (RT) using a concomitant intensity-modulated RT boost in conjunction with elective pelvic nodal irradiation for high-risk prostate cancer. Methods and Materials: This report focused on 66 patients entered into this prospective Phase I study. The ...

Proton beams are more advantageous than high-energy photons and electrons for radiation therapy because of their finite penetrating range and the Bragg peak near the end of their range, which have been utilized to achieve better dose conformity to the treatment target allowing for dose escalation and/or hypofractionation to increase local tumor control, reduce normal tissue ...

Radiotherapy (RT) after tumorectomy in early breast cancer patients is an established treatment modality which conventionally takes 6-7 wk to complete. Shorter RT schedules have been tested in large multicentre randomized trials and have shown equivalent results to that of standard RT (50 Gy in 25 fractions) in terms of local tumor control, patient survival and late post-radiation effects. Some of ...

There is a clear dose response for localized prostate cancer radiotherapy and there probably is a radiobiological rationale for hypo-fractionation. Combining the two should maximize tumor control and increase the therapeutic ratio. This study examines the rationale and technical feasibility of CyberKnife radiotherapy (a robotic arm-driven linear ...

Radiotherapy (RT) after tumorectomy in early breast cancer patients is an established treatment modality which conventionally takes 6-7 wk to complete. Shorter RT schedules have been tested in large multicentre randomized trials and have shown equivalent results to that of standard RT (50 Gy in 25 fractions) in terms of local tumor control, patient survival and late post-radiation effects. Some of ...

The kV cone beam CT (CBCT) consists of an X-ray tube and a flat panel detector placed perpendicularly to the treatment beam, allowing the acquisition of hundreds of projections in one rotation of the gantry about the patient. Available in all new linear accelerators, the CBCT provides volumetric imaging in treatment position proving the realization of image- and dose-guided ...

Purpose: Despite multimodality treatments, the outcome of patients with glioblastoma multiforme remains poor. In an attempt to improve results, we have begun a program of accelerated hypofractionated intensity-modulated radiotherapy (hypo-IMRT) with concomitant and adjuvant temozolomide (TMZ). Methods and Materials: Between March 2004 ...

This project clearly demonstrates that intensity modulated electron arc radiotherapy is feasible using the photon multi-leaf collimator of a modern linear accelerator. Secondary and tertiary collimators are replaced by the multi-leaf collimator and by dyn...

New technologies such as intensity modulated and image guided radiation therapy, computer controlled linear accelerators, record and verify systems, electronic charts, and digital imaging have revolutionized radiation therapy over the past 10-15 y. Quality assurance (QA) as historically practiced and as recommended in reports such as ...

Purpose: To report interim cosmetic results and toxicity from a prospective study evaluating accelerated partial-breast irradiation (APBI) administered using a highly conformal external beam approach. Methods and Materials: We enrolled breast cancer patients in an institutional review board-approved prospective study of APBI using beamlet ...

Purpose: Dose escalation for prostate cancer improves biological control but with a significant increase in late toxicity. Recent estimates of low {alpha}/{beta} ratio for prostate cancer suggest that hypofractionation may result in biological advantage. Intensity-modulated radiotherapy (IMRT) should enable dose escalation to the prostate while reducing ...

Although helical tomotherapy has been described as a means of administering accelerated partial breast irradiation, its practicality in routine whole breast irradiation as part of breast conserving therapy or chest wall irradiation has been questioned. In this technical note we describe our method of whole breast or chest wall irradiation using helical tomotherapy based ...

Since the discovery of X-rays, the goal of radiotherapy has been to deliver an optimal dose in the target volume and the lowest possible dose in the normal tissues. The history of radiotherapy can be divided in three periods. The Kilovoltage era (1900-1939) where only superficial and radiosensitive tumours could be controlled, the Megavoltage era (1950-1995) where Telecobalt and linear ...

Purpose: To evaluate tumor and normal tissue dosimetry of a 5 cobalt gray equivalent (CGE) x 5 fraction proton radiotherapy schedule, before initiating a clinical trial of neoadjuvant, short-course proton radiotherapy for pancreatic adenocarcinoma. Methods and Materials: The first 9 pancreatic cancer patients treated with neoadjuvant intensity-modulated radiotherapy (1.8 Gy x ...

Intensity-modulated fiber Bragg grating (FBG) sensors, compared with normal wavelength-encoding FBG sensors, can reduce the cost of sensor system significantly by using cost-efficient optical power detection devices, instead of expensive wavelength measurement instruments. Chirped-FBG (CFBG) based intensity-modulated sensors show potential applications in ...

The beam-on time for intensity modulated radiation therapy (IMRT) is increased significantly compared with conventional radiotherapy treatments. Further, the presence of beam modulation devices may potentially affect neutron production. Therefore, neutron measurements were performed for 15 MV photon beams on a Varian Clinac accelerator ...

Hypofractionated stereotactic body radiotherapy (SBRT) has been tested for prostate cancer radiotherapy. This study aims to investigate the dosimetric effects of intrafraction prostate motion on the target and the normal structures for SBRT. For prostate cancer patients treated with an image-tracking CyberKnife system, the intrafraction prostate movements were recorded during ...

PURPOSE: To report the acute and late toxicities of patients with high-risk localized prostate cancer treated using a concomitant hypofractionated, intensity-modulated radiotherapy boost combined with long-term androgen deprivation therapy. METHODS AND MATERIALS: A prospective Phase I-II study of patients with any of the following: clinical Stage T3 ...

PurposeTo assess results of a multi-institutional study of Intensity-Modulated Radiation Therapy (IMRT) for early oropharyngeal cancer.Patients and MethodsPatients with oropharyngeal carcinoma stage T1-2, N0-1, M0 requiring treatment of the bilateral neck were eligible. Chemotherapy was not permitted. Prescribed planning target volumes (PTVs) doses to primary tumor and involved nodes was 66 Gy at ...

Purpose: To assess the results of a multi-institutional study of intensity-modulated radiation therapy (IMRT) for early oropharyngeal cancer. Patients and Methods: Patients with oropharyngeal carcinoma Stage T1-2, N0-1, M0 requiring treatment of the bilateral neck were eligible. Chemotherapy was not permitted. Prescribed planning target volumes (PTVs) doses to primary tumor and involved nodes was ...

Purpose: To determine the safety and efficacy of preoperative hypofractionated radiotherapy using intensity-modulated radiotherapy (IMRT) and an incorporated boost with concurrent capecitabine in patients with locally advanced rectal cancer. Methods and Materials: The eligibility criteria included adenocarcinoma of the rectum, T3-T4 and/or N1-N2 disease, ...

Purpose: To determine the planning results and acute toxicity after hypofractionated intensity-modulated arc radiotherapy and androgen deprivation for lymph node metastasized (Stage N1) prostate cancer. Methods and Materials: A total of 31 patients with Stage T1-T4N1M0 prostate cancer were treated with intensity-modulated arc radiotherapy and 3 years of ...

Reirradiation is a feasible option for patients who do not otherwise have treatment options available. Depending on the location and extent of the tumor, reirradiation may be accomplished with external beam radiotherapy, brachytherapy, radiosurgery, or intensity modulated radiation therapy (IMRT). Although there has been limited experience with ...

ABSTRACT: Reirradiation is a feasible option for patients who do not otherwise have treatment options available. Depending on the location and extent of the tumor, reirradiation may be accomplished with external beam radiotherapy, brachytherapy, radiosurgery, or intensity modulated radiation therapy (IMRT). Although there has been limited experience with ...

Purpose: To evaluate whether hypofractionation is well tolerated and to preliminarily assess biochemical control of this regimen in a postprostatectomy, salvage setting. Methods and Materials: A retrospective analysis was performed in 50 patients treated between May 2003 and December 2005 with hypofractionated radiotherapy for biochemical recurrence after ...

Purpose: To assess in a prospective trial the feasibility and late toxicity of hypofractionated radiotherapy (RT) for prostate cancer. Methods and Materials: Eligible patients had clinical stage T1c-2cNXM0 disease. They received 60 Gy in 20 fractions over 4 weeks with intensity-modulated radiotherapy including daily on-line image guidance with intraprostatic fiducial markers. ...

Purpose: To describe the radiation-induced acute rectal toxicity (ART) using a modified Lyman-Kutcher-Burman normal tissue complication probability model and parameters set, taking into account the overall treatment time. Methods and Materials: A total of 160 patients underwent three-dimensional conformal radiotherapy to the prostate and seminal vesicles and were randomized to receive 80 Gy in 40 ...

Margin reduction for prostate radiotherapy is limited by uncertainty in prostate localization during treatment. We investigated the feasibility and accuracy of measuring prostate intrafraction motion using kV fluoroscopy performed simultaneously with radiotherapy. Three gold coils used for target localization were implanted into the patient's prostate gland before undergoing ...

Margin reduction for prostate radiotherapy is limited by uncertainty in prostate localization during treatment. We investigated the feasibility and accuracy of measuring prostate intrafraction motion using kV fluoroscopy performed simultaneously with radiotherapy. Three gold coils used for target localization were implanted into the patient�s prostate gland before undergoing ...

Margin reduction for prostate radiotherapy is limited by uncertainty in prostate localization during treatment. We investigated the feasibility and accuracy of measuring prostate intrafraction motion using kV fluoroscopy performed simultaneously with radiotherapy. Three gold coils used for target localization were implanted into the patient's prostate gland before undergoing ...

Purpose: To analyze the long-term relapse-free survival and toxicity rates in patients treated with hypofractionated intensity-modulated radiotherapy. Methods and Materials: The study sample includes the first 100 consecutive localized prostate cancer patients treated to 70.0 Gy at 2.5 Gy per fraction. The median follow-up was 66 months (range, 3 to 75 ...

Purpose: To evaluate the feasibility, tolerability, and preliminary outcomes in patients with prostate cancer treated according to a hypofractionated dose escalation protocol to boost the dominant tumor-bearing region of the prostate. Methods and Materials: After conventional fractionated external radiotherapy to 64 to 64.4Gy, 50 patients with nonmetastatic prostate cancer ...

Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradie...

Radiobiological data suggest that prostate cancer has a low {alpha}/{beta} ratio. Large radiotherapy fractions may, therefore, prove more efficacious than standard radiotherapy, while radiotherapy acceleration should further improve control rates. This study describes the radiobiology of a conformal hypofractionated accelerated ...

Early breast cancer incidence increases owing to mammography screening. Hypofractionated radiotherapy is more and more proposed in women with low local relapse risk breast cancer, especially accelerated partial breast irradiation. Various irradiation modalities have been reported: brachytherapy, intraoperative irradiation, 3D-conformal ...

Respiration-induced tumor motion during intensity modulated radiotherapy (IMRT) of non-small cell lung cancer (NSCLC) could cause substantial differences between planned and delivered doses. However, it has been shown that for conventionally fractionated IMRT motion effects average out over the course of many treatments, but this might not be true for ...

Proton beams can provide better dose conformity to the treatment target compared to commonly used photon and electron beams allowing for dose escalation and/or hypofractionation to increase local tumor control, reduce normal tissue complications and/or treatment time/cost. This paper reviews three novel proton accelerator designs that aim at cost-effective ...

PURPOSE: To determine if principal component analysis (PCA) and standard parameters of rectal and bladder wall dose-volume histograms (DVHs) of prostate cancer patients treated with hypofractionated image-guided intensity-modulated radiotherapy (hypo-IMRT) can predict acute and late gastrointestinal (GI) toxicity. METHODS AND MATERIALS: One hundred ...

Purpose: To study the outcomes in patients treated for localized prostate cancer with 70 Gy delivered at 2.5-Gy/fraction within 5 weeks. Methods and Materials: The study sample included all 770 consecutive patients with localized prostate cancer treated with hypofractionated intensity-modulated radiotherapy at the Cleveland Clinic between 1998 and 2005. ...

BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated high-risk prostate cancer treatment.Methods3DCRT and dIMRT/Helical Tomotherapy(HT) planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 ...

Purpose: To report acute toxicity resulting from radiotherapy (RT) dose escalation and hypofractionation using intensity-modulated RT (IMRT) treatment combined with androgen suppression in high-risk prostate cancer patients. Methods and Materials: Sixty patients with a histological diagnosis of high-risk prostatic adenocarcinoma (having either a clinical ...

Purpose: Standard radiation for early breast cancer requires daily treatment for 6 to 7 weeks. This is an inconvenience to many women, and for some a barrier for breast conservation. We present the acute toxicity of a 4-week course of hypofractionated radiation. Methods and Materials: A total of 75 patients completed radiation on a Phase II trial approved by the hospital ...

Purpose: The {alpha}/{beta} ratio for prostate cancer is postulated to be between 1 and 3, giving rise to the hypothesis that there may be a therapeutic advantage to hypofractionation. The dosimetry and acute toxicity are described in the first 100 men enrolled in a randomized trial. Patients and Methods: The trial compares 76 Gy in 38 fractions (Arm I) to 70.2 Gy in 26 ...

Arc-modulated radiation therapy (AMRT) is a novel rotational intensity-modulated radiation therapy (IMRT) technique developed for a clinical linear accelerator that aims to deliver highly conformal radiation treatment using just one arc of gantry rotation. Compared to fixed-gantry IMRT and the multiple-arc intensity-modulated arc ...

Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are ...

In this paper we present Monte Carlo studies of intensity modulated radiation therapy using laser-accelerated proton beams. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic ...

The state of the art Intensity Modulate Radiation Therapy (IMRT) has been one of the most significant breakthroughs in the cancer treatment in the past 30 years. There are two types of IMRT systems. The first system is the binary-based tomotherapy, represented by the Peacock (Nomos Corp) and Tomo unit (TomoTherapy Inc.), adopting specific binary collimator ...

Purpose: To investigate the tumor control rates in locally advanced head-and-neck cancer using accelerated hypofractionated radiotherapy with chemotherapy. Methods and Materials: The data from patients with squamous cell cancer of the larynx, oropharynx, oral cavity, and hypopharynx (International Union Against Cancer Stage II-IV), who received ...

A currently used intensity-modulated radiotherapy system is the TomoTherapy� Hi-Art� accelerator (Tomotherapy Inc., Madison, WI, USA), which started clinical treatments at the beginning of the new millennium. The innovative idea behind tomotherapy units is to marry an x-ray computed tomography unit with a linear particle ...

The success of stereotactic radiosurgery has stimulated significant interest in the application of such an approach for the treatment of extracranial tumors. The potential benefits of reduced healthcare costs and improved patient outcomes that could be realized in a high-precision, hypofractionated treatment paradigm are numerous. Image-guidance technologies are eliminating ...

The dosimetric consequences of plans optimized using a commercial treatment planning system (TPS) for hypofractionated radiation therapy are evaluated by re-calculating with Monte Carlo (MC). Planning guidelines were in strict accordance with the Canadian BR25 protocol which is similar to the RTOG 0236 and 0618 protocols in patient eligibility and total dose, but has a ...

Approximately 40-50% of children with cancer will be irradiated during their treatment. Intensity-modulated radiotherapy (IMRT) by linear accelerator or helical tomotherapy improves dose distribution in target volumes and normal tissue sparing. This technology could be particularly useful for pediatric patients to achieve an optimal dose distribution in ...

... using electron and intensity modulated photon was developed. ... of the two types of beams and showed ... the weight of the electron beam and the ...

PURPOSE: To evaluate, with a dosimetric and clinical feasibility study, RapidArc (a volumetric modulated arc technique) for hypofractionated stereotactic radiotherapy treatment of large arteriovenous malformations (AVMs). METHODS AND MATERIALS: Nine patients were subject to multimodality imaging (magnetic resonance, computed tomography, and digital subtraction angiography) to ...

In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due ...

BackgroundRadiation therapy after lumpectomy is a standard part of breast conserving therapy for invasive breast carcinoma. The most frequently used schedule worldwide is 60 Gy in 30 fractions in 6 weeks, a time commitment that sporadically may dissuade some otherwise eligible women from undertaking treatment. The purpose and primary endpoint of this perspective study is to evaluate feasibility ...

A method of hypofractionated accelerated radiotherapy (3 weekly fractions of 6 Gy over 2 weeks to a total tumor dose of 36 Gy) was used as single modality in 14 patients with osteogenic sarcoma for palliative treatment of the primary tumor site (six cases) or skeletal metastases (15 sites). A durable response, radiologically assessed, was obtained in 17 of ...

Intrinsic radioresistance, tumor hypoxia and ability of cancer cells to undergo rapid repopulation during radiotherapy are associated with failure of radiotherapy. Tumors with low alpha/beta-ratio values or hypoxic tumors unable to undergo re-oxygenation, are unlikely to be eradicated with standard radiotherapy. Although the therapeutic efficacy of accelerated regimens based ...

BackgroundAccelerated hypofractionation is an attractive approach for adjuvant whole breast radiotherapy. In this study we evaluated the adverse effects at least 3 years post an accelerated hypofractionated whole breast radiotherapy schedule.MethodsFrom October 2004 to March 2006, 39 consecutive patients aged over ...

Modern breast cancer radiotherapy aims to increase uncomplicated cure rates. A priority is reduction of late effects which include chronic chest wall or breast pain, poor cosmesis, and cardiac toxicity. As breast screening detects early cancers we may be able to safely restrict irradiation postlumpectomy to the tumour bed with a margin, defining a 'partial breast' target volume for treatment. ...

The development of advanced intensity modulated radiation therapy (IMRT) techniques has led to significant improvements in our ability to treat complicated target volumes with minimal collateral damage to the surrounding healthy tissue. These techniques however, come at the cost of increased complexity; which translates into increased sensitivity of the ...

The implementation of intensity modulated radiotherapy by dynamic multileaf collimator control involves the use of interpreter software which creates leaf trajectory plans for each leaf pair. Interpreter software for use with an Elekta SL15 linear accelerator and dedicated multileaf collimator has been written and tested. In practice ...

Intensity modulated arc therapy (IMAT) is a radiation therapy technique whereby the shape of the cone beam of radiation changes as it rotates around the patient. This is in contrast to other more commonly delivered forms of advanced radiation therapy, Intensity Modulated Radiation Therapy (IMRT) or helical ...

Optical-fiber sensors which are based on intensity modulation of light are examined. The optical-fiber sensors consists of a glass core, a cladding, a light emitting diode or laser, and a photodetector, and are applicable to measuring instruments, medical probes, control systems, and military surveillance and navigation systems. The designs and ...

In intensity-modulated radiation therapy (IMRT), the aim is to deliver reduced doses of radiation to normal tissue. As a step toward IMRT, we examined dynamic optical modulation of an electron beam produced by a photocathode RF gun. Images on photomasks were transferred onto a photocathode by relay imaging. The resulting beam was controlled by a remote mirror. The modulated electron beam ...

Purpose: To correlate the treatment planning parameters with the clinical outcomes in patients treated with accelerated partial breast intensity-modulated radiotherapy. Methods and Materials: A total of 105 patients with Stage I breast cancer were treated between February 2004 and March 2007 in a Phase II prospective trial and had detailed information ...

A novel compact CT-guided intensity modulated proton radiotherapy (IMPT) system is described. The system is being designed to deliver fast IMPT so that larger target volumes and motion management can be accomplished. The system will be ideal for large and complex target volumes in young patients. The basis of the design is the dielectric wall ...

Hyperfractionation and hypofractionation combined with acceleration have been investigated in stage I-III NSCLC patients. In stage I tumors, hypofractionated radiation schedules given with highly conformal stereotactic body radiotherapy (SBRT) techniques have been proven safe and effective with local control rates > 85% and ...

... Title : Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed after Segmental Mastectomy. Descriptive Note : Final addendum rept. ...

... Title : Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed After Segmental Mastectomy. Descriptive Note : Final rept. ...

... Title : Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed After Segmental Mastectomy. Descriptive Note : Final rept. ...

... Title : Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed after Segmental Mastectomy. Descriptive Note : Annual rept. ...

... Title : Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed After Segmental Mastectomy. Descriptive Note : Annual rept. ...

? Breast conservation is a safe and effective alternative to mastectomy for the majority of women with early-stage breast cancer. Adjuvant radiation therapy lowers the risk of recurrence within the breast and also confers a survival benefit. Although acute side effects of radiation therapy are generally well tolerated; efforts are ongoing to minimize the long-term side effects of radiation, most ...

A treatment planning comparison study was performed to evaluate the dosimetric characteristic and treatment efficiency of volumetric modulated arc therapy with step-and-shoot intensity modulated radiotherapy (IMRT) for the hypofractionated stereotactic radiotherapy (HFSRT) in patients with multiple brain metastases. CT datasets of 10 ...

In conventional linear accelerators, the flattening filter provides a uniform lateral dose profile. In intensity modulated radiation therapy applications, however, the flatness of the photon field and hence the presence of a flattening filter, is not necessary. Removing the filter may provide some advantages, such as faster treatments ...

In conventional linear accelerators, the flattening filter provides a uniform lateral dose profile. In intensity modulated radiation therapy applications, however, the flatness of the photon field and hence the presence of a flattening filter, is not necessary. Removing the filter may provide some advantages, such as faster treatments ...

Intensity-modulated radiation therapy (IMRT) is essential to have a dose distribution matching with the planning target volume (PTV) in case of concave-shape target. Today IMRT delivery techniques with linear accelerator can be divided into two classes: techniques with fixed gantry, called "step and shoot" (S&S) and "sliding window" (SW), and ...

Helical tomotherapy (HT) is a novel treatment approach that combines Intensity-Modulate Radiation Therapy (IMRT) delivery with in-built image guidance using megavoltage (MV) CT scanning. The technique utilises a 6 MV linear accelerator mounted on a CT type ring gantry. The beam is collimated to a fan beam, which is intensity ...

In this note it is shown how the use of a rotate-translate methodology employing only jaws, which move dynamically with the beam continuously on, can lead to a delivery of a two-dimensional intensity-modulated beam wherein the modulation is spatially slowly varying. All that is necessary is that a pair of jaws sweep across the face of an accelerator with ...

The use of megavoltage electron beams often poses a clinical challenge in that the planning target volume (PTV) is anterior to other radiosensitive structures and has variable depth. To ensure that skin as well as the deepest extent of the PTV receives the prescribed dose entails prescribing to a point beyond the depth of peak dose for a single electron energy. This causes dose inhomogeneities and ...

An independent dose calculation method has been developed to validate intensity-modulated radiation therapy (IMRT) plans from the NOMOS PEACOCK System. After the plan is generated on the CORVUS planning system, the beam parameters are imported into an independent workstation. The beam parameters consist of intensity maps at each gantry angle and each arc position. In addition, ...

An efficient method for volumetric intensity modulated arc therapy (VMAT) planning was developed, where a single arc (360 degrees or less) is delivered under continuous variation of multileaf collimator (MLC) segments, dose rate, and gantry speed. Plans can be generated for any current linear accelerator that supports these degrees of ...

The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a multileaf collimator quality assurance ...

Page 1. AD Award Number: DAMD17-03-1-0023 TITLE: Intensity Modulated Radiation Treatment of Prostate Cancer Guided ...

... Title : Combining Electron with Intensity Modulated Photon Beams for Breast Cancer. Descriptive Note : Annual rept. 1 Jul 2001-30 Jun 2002. ...

A simple analytical model is found that predicts the exact proton spectrum needed to obtain a spread-out-Bragg peak (SOBP) distribution for laser-accelerated proton beams. The theory is based on the solution to the Boltzmann kinetic equation for the proton distribution function. The resulting analytical expression allows one to calculate the SOBP proton energy spectra for the ...

Purpose: A sequential two-phase process, initial and boost irradiation, is the common practice for the radiotherapy management of high-risk prostate cancer. In this work, we explore the feasibility of using intensity modulated radiation therapy (IMRT) simultaneous integrated boost (SIB), a single-phase process, to simultaneously deliver high dose to the ...

Purpose: To evaluate the efficacy and toxicity of hypofractionated conventional conformation radiotherapy (HCCRT) with noninvasive fixation of the skull on patients with single or several brain metastases. Methods and Materials: The subjects were 44 patients who had three or fewer brain metastases (26 solitary, 18 multiple). Treatment was conducted on 65 metastases by ...

Purpose: To measure and compare neutron fluence around an accelerator operating at 18 MV, both with the flattening filter present (FF mode) and absent (flattening-filter-free [FFF] mode). Methods and Materials: The neutron fluence was measured at several locations in the patient plane using gold foil activation in neutron moderators. Differences in neutron fluence between the ...

Recent clinical trials of hypofractionated radiation treatment have provided critical insights into the safety and efficacy of hypofractionation. However, there remains much controversy in the field, both at the level of clinical practice and in our understanding of the underlying radiobiological mechanisms. In this article, we review the clinical ...

Radiotherapy has undergone significant technological advances during the last 20 years, although their use in breast cancer was relatively limited until recently. The major recent changes in the use of radiotherapy for breast cancer have been the following: the establishment of partial breast irradiation (PBI) as an option for therapy in early stage disease; the revival of ...

The main aim of radiotherapy is to deliver a dose of radiation that is high enough to destroy the tumour cells while at the same time minimising the damage to normal healthy tissues. Clinically, this has been achieved by assigning a prescription dose to the tumour volume and a set of dose constraints on critical structures. Once an optimal treatment plan has been achieved the dosimetry is assessed ...

The authors present a segment-based convolution method to account for the interplay effect between intrafraction organ motion and the multileaf collimator position for each particular segment in intensity modulated radiation therapy (IMRT) delivered in a step-and-shoot manner. In this method, the static dose distribution attributed to each segment is ...

The authors present a segment-based convolution method to account for the interplay effect between intrafraction organ motion and the multileaf collimator position for each particular segment in intensity modulated radiation therapy (IMRT) delivered in a step-and-shoot manner. In this method, the static dose distribution attributed to each segment is ...

Radiochromic film is a self developing two-dimensional dosimeter system that is widely used in radiotherapy. Since its development some 40 years ago many improvements have been made; however the sensitivity can vary across the film and a non-linear dose response remains. The former can be addressed using a double exposure technique; however this technique assumes that the response is linear so ...

In their classic paper, Yu et al (1998 Phys. Med. Biol. 43 91) investigated the interplay between tumor motion caused by breathing and dynamically collimated, intensity-modulated radiation delivery. The paper's analytic model assumed an idealized, sinusoidal pattern of motion. In this work, we investigate the effect of tumor motion based on patients' breathing patterns for ...

For prostate cancer patients, online image-guided (IG) radiotherapy has been widely used in clinic to correct the translational inter-fractional motion at each treatment fraction. For uncertainties that cannot be corrected online, such as rotation and deformation of the target volume, margins are still required to be added to the clinical target volume (CTV) for the treatment planning. Offline ...

As a clinical application of an exciting scientific breakthrough, a compact and cost-efficient proton therapy unit using high-power laser acceleration is being developed at Fox Chase Cancer Center. The significance of this application depends on whether or not it can yield dosimetric superiority over intensity-modulated radiation therapy (IMRT). The goal ...

Purpose: To assess the feasibility of intensity-modulated radiotherapy for prostate cancer using photon beams from an accelerator operated without a flattening filter; and to determine potential benefits and drawbacks of using unflattened beams for this type of treatment. Methods and Materials: Intensity-modulated radiotherapy plans were generated for 10 ...

PURPOSE: To compare intensity-modulated arc therapy (IMAT) to noncoplanar intensity-modulated radiation therapy (IMRT) in the treatment of pediatric posterior fossa tumors. METHODS AND MATERIALS: Nine pediatric patients with posterior fossa tumors, mean age 9 years (range, 6-15 years), treated using IMRT were chosen for this comparative planning study ...

Intensity-modulated radiation therapy (IMRT) is a 3D conformal radiation therapy technique that utilizes either a multileaf intensity-modulating collimator (MIMiC used with the NOMOS Peacock system) or a multileaf collimator (MLC) on a conventional linear accelerator for beam intensity ...

Intensity-modulated radiation therapy (IMRT) is commonly delivered using the dynamic or segmental mode of multileaf collimators (DMLC or SMLC). Both methods are designed to deliver intensity-modulated beams as determined by inverse planning software. In this study, we have used the Helios IMRT planning system to generate ideal treatment plans for 10 cases ...