Publications by authors named "Hideki Hirata"

Background: Radiotherapy (RT) destroys cancer cells and activates the immune system while suppressing the immunity of tumor-associated tissues, including the tumor microenvironment (TME). However, to date, no anti-tumor therapeutic strategy that uses these immune mechanisms has been established. This study investigated changes in the immunity of the TME during standard radical RT for cervical cancer combined with external beam RT and brachytherapy and determined whether these changes affect prognosis.

View Article and Find Full Text PDF

Objective: Concurrent chemoradiotherapy is the standard treatment for locally advanced non-small cell lung cancer. In the current aging society, the establishment of an ideal treatment strategy for locally advanced non-small cell lung cancer in the elderly is warranted. To assess the efficacy of concurrent chemoradiotherapy with carboplatin and vinorelbine in elderly patients with locally advanced non-small cell lung cancer.

View Article and Find Full Text PDF

The present study compares dosimetric parameters between volumetric-modulated arc therapy (VMAT) and 3D conformal radiation therapy (3D-CRT) in lung tumors adjacent to the chest wall treated with stereotactic body radiation therapy (SBRT). The study focused on the radiation dose to the chest wall of 16 patients who had developed radiation-induced rib fractures (RIRF) after SBRT using 3D-CRT. The targets in all patients were partially overlapping with the fractured ribs, and the median overlapping rib-PTV distance was 0.

View Article and Find Full Text PDF

Purpose: Hyperthermia (HT), an adjuvant therapy for variable cancers, may cause physiological changes in the patients, which may lead to cardiovascular problems. Among various HT treatments, the physiological effects of deep regional HT are still unclear. We examined the physiological alterations throughout deep regional HT to improve the HT safety.

View Article and Find Full Text PDF

This study investigates whether in-room computed tomography (CT)-based adaptive treatment planning (ATP) is robust against interfractional location variations, namely, interfractional organ motions and/or applicator displacements, in 3D intracavitary brachytherapy (ICBT) for uterine cervical cancer. In ATP, the radiation treatment plans, which have been designed based on planning CT images (and/or MR images) acquired just before the treatments, are adaptively applied for each fraction, taking into account the interfractional location variations. 2D and 3D plans with ATP for 14 patients were simulated for 56 fractions at a prescribed dose of 600 cGy per fraction.

View Article and Find Full Text PDF

Purpose: The purpose of this study was to evaluate the effect of prostate matching on dose distribution using kilovolt cone beam computed tomography (kV-CBCT) with image guided radiation therapy for prostate cancer.

Materials And Method: Sixteen prostate cancer patients were treated with intensity modulated radiation therapy to 76 Gy at 2 Gy per fraction in 38 fractions. Daily target localization was performed using "bone matching" and "prostate matching" based on planning CT and kV-CBCT.

View Article and Find Full Text PDF

Objective: To investigate the feasibility of an automated framework for estimating the lung tumor locations for tumor-based patient positioning with megavolt-cone-beam computed tomography (MV-CBCT) during stereotactic body radiotherapy (SBRT).

Methods: A lung screening phantom and ten lung cancer cases with solid lung tumors, who were treated with SBRT, were employed to this study. The locations of tumors in MV-CBCT images were estimated using a tumor-template matching technique between a tumor template and the MV-CBCT.

View Article and Find Full Text PDF

A computerized framework for monitoring four-dimensional (4D) dose distributions during stereotactic body radiation therapy based on a portal dose image (PDI)-based 2D/3D registration approach has been proposed in this study. Using the PDI-based registration approach, simulated 4D "treatment" CT images were derived from the deformation of 3D planning CT images so that a 2D planning PDI could be similar to a 2D dynamic clinical PDI at a breathing phase. The planning PDI was calculated by applying a dose calculation algorithm (a pencil beam convolution algorithm) to the geometry of the planning CT image and a virtual water equivalent phantom.

View Article and Find Full Text PDF

CyberKnife(®) provides continuous guidance through radiography, allowing instantaneous X-ray images to be obtained; it is also equipped with 6D adjustment for patient setup. Its disadvantage is that registration is carried out just before irradiation, making it impossible to perform stereo-radiography during irradiation. In addition, patient movement cannot be detected during irradiation.

View Article and Find Full Text PDF

We evaluated the predictive factors of acute urinary morbidity (AUM) after prostate brachytherapy. From November 2005 to January 2007, 62 patients with localized prostate cancer were treated using brachytherapy. The (125)Iodine ((125)I) seed-delivering method was a modified peripheral pattern.

View Article and Find Full Text PDF

To assist radiation oncologists in the delineation of tumor regions during treatment planning for lung cancer, we have proposed an automated contouring algorithm based on an optimum contour selection (OCS) method for treatment planning computed tomography (CT) images with positron emission tomography (PET)/CT images. The basic concept of the OCS is to select a global optimum object contour based on multiple active delineations with a level set method around tumors. First, the PET images were registered to the planning CT images by using affine transformation matrices.

View Article and Find Full Text PDF

Aim: To retrospectively evaluate the efficacy and safety of definitive fractionated re-irradiation for local recurrence following stereotactic body radiotherapy (SBRT) for primary lung cancer.

Patients And Methods: Between April 2003 and December 2011, 398 patients with primary lung tumor underwent SBRT at the Kyushu University Hospital, and 46 out of these developed local recurrence after SBRT. Definitive fractionated re-irradiation was performed for 17 out of the 46 patients.

View Article and Find Full Text PDF

Objective: To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners.

Methods: First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique.

View Article and Find Full Text PDF

Objectives: The aim of the study was to investigate the outcomes of high-dose-rate interstitial radiation therapy for patients with Stage I and II mobile tongue cancer retrospectively.

Methods: Sixty-seven patients with Stage I and II mobile tongue cancer were treated with high-dose-rate interstitial radiation therapy, with or without external beam radiation therapy, between 1997 and 2007. The median dose of interstitial radiation therapy was 50 Gy in 10 fractions over 6 days.

View Article and Find Full Text PDF

This study sought to investigate the clinical outcome and the role of postoperative radiotherapy for patients with salivary duct carcinoma (SDC) who had undergone surgery and postoperative radiotherapy. We performed a retrospective analysis of 25 SDC patients treated between 1998 and 2011 with surgery and postoperative radiotherapy. The median prescribed dose was 60 Gy (range, 49.

View Article and Find Full Text PDF

The purpose of this study was to develop a computer-aided method for determination of beam arrangements based on similar cases in a radiotherapy treatment-planning database for stereotactic lung radiation therapy. Similar-case-based beam arrangements were automatically determined based on the following two steps. First, the five most similar cases were searched, based on geometrical features related to the location, size and shape of the planning target volume, lung and spinal cord.

View Article and Find Full Text PDF

The purpose of this study was to evaluate the treatment outcomes of stereotactic body radiotherapy (SBRT) for Stage I small-cell lung cancer (SCLC). From April 2003 to September 2009, a total of eight patients with Stage I SCLC were treated with SBRT in our institution. In all patients, the lung tumors were proven as SCLC pathologically.

View Article and Find Full Text PDF

We have developed a computerized method for estimating patient setup errors in portal images based on localized pelvic templates for prostate cancer radiotherapy. The patient setup errors were estimated based on a template-matching technique that compared the portal image and a localized pelvic template image with a clinical target volume produced from a digitally reconstructed radiography (DRR) image of each patient. We evaluated the proposed method by calculating the residual error between the patient setup error obtained by the proposed method and the gold standard setup error determined by consensus between two radiation oncologists.

View Article and Find Full Text PDF

Purpose: The purpose of this study was to clarify the incidence, the clinical risk factors, and the dose-volume relationship of radiation-induced rib fracture (RIRF) after hypofractionated stereotactic body radiation therapy (SBRT).

Methods And Materials: One hundred sixteen patients treated with SBRT for primary or metastatic lung cancer at our institution, with at least 6 months of follow-up and no previous overlapping radiation exposure, were included in this study. To determine the clinical risk factors associated with RIRF, correlations between the incidence of RIRF and the variables, including age, sex, diagnosis, gross tumor volume diameter, rib-tumor distance, and use of steroid administration, were analyzed.

View Article and Find Full Text PDF

One of the unusual patterns of local recurrence in breast cancer patient is an inflammatory skin recurrence (ISR) sharply demarcating the area of previous radiation fields. To clarify the characteristics of this recurrence, we conducted a nationwide survey. We sent a survey to radiation oncologists at 200 institutions in Japan and received answers from 92.

View Article and Find Full Text PDF

Objectives: To assess the efficacy and toxicity of radical chemoradiotherapy for patients with synchronous head and neck squamous cell carcinoma (HNSCC) and esophageal cancer (EC).

Methods: Thirty-four patients with synchronous HNSCC and EC were treated mainly with radical chemoradiotherapy at the same time. Median external radiation dose for HNSCC and EC was 70 Gy (range, 60-70.

View Article and Find Full Text PDF

We report a case of radiation fibrosis appearing as mass-like consolidation, which was difficult to distinguish from local recurrence. A 72-year-old woman was diagnosed as having primary lung cancer (cT1N0M0 stage IA) in the right upper lobe and was treated with SBRT of 48 Gy in 4 fractions. After 12 months, mass-like consolidation appeared around the irradiated area, and after 13 months, it had increased in size.

View Article and Find Full Text PDF

Purpose: Small-cell esophageal carcinoma (SCEC) is a rare disease for which standard therapy has not yet been established. We report the results of three cases of limited-stage SCEC treated with combination therapy using carboplatin (CBDCA) and etoposide (VP-16) and radiotherapy.

Materials And Methods: The clinical stage according to the Japanese Classification of Esophageal Cancer 7th ed.

View Article and Find Full Text PDF

Introduction: Primary malignant melanoma of the esophagus is a rare but highly aggressive tumor with poor prognosis. Surgical resection is the treatment of choice. However, some cases may be diagnosed with advanced inoperable disease.

View Article and Find Full Text PDF