Developing a novel quasi-3D movable water phantom for radiation therapy workable in the magnetic resonance environment.

Background: The use of magnetic resonance linear accelerators (MR-LINACs) for clinical treatment has opened up new possibilities and challenges in the field of radiation oncology. However, annual quality assurance (QA) is relatively understudied due to practical considerations. Thus, to overcome the difficulty of measuring the dose with a small water phantom for TRS-398 or TG-51 in all external beam radiation treatment unit environments, such as MR compatibility, we designed a remote phantom with a three-axis changeable capacity for QA.

Low cost multifunctional 3D printed image quality and dose verification phantom for an image-guided radiotherapy system.

Purpose: Image-guided radiation therapy (IGRT) is used to precisely deliver radiation to a tumour to reduce the possible damage to the surrounding normal tissues. Clinics use various quality assurance (QA) equipment to ensure that the performance of the IGRT system meets the international standards set for the system. The objective of this study was to develop a low-cost and multipurpose module for evaluating image quality and dose.

Design of a motion simulation system to assist respiratory gating for radiation therapy.

Unlabelled: Stereotactic ablative radiotherapy (SABR) aims to deliver high doses of radiation to kill cancer cells and shrink tumors in less than or equal to 6 fractions. However, organ motion during treatment is a challenging issue for this kind of technique. We develop a control system via Bluetooth technology to simulate and correct body motion during SABR.

Impact of breath-hold level on positional error aligned by stent/Lipiodol in Hepatobiliary radiotherapy with breath-hold respiratory control.

Background: Respiratory motion management with breath hold for patients with hepatobiliary cancers remain a challenge in the precise positioning for radiotherapy. We compared different image-guided alignment markers for estimating positional errors, and investigated the factors associated with positional errors under breath-hold control.

Methods: Spirometric motion management system (SDX) for breath holds was used in 44 patients with hepatobiliary tumor.

Reduced incidence of interstitial pneumonitis after allogeneic hematopoietic stem cell transplantation using a modified technique of total body irradiation.

Allogeneic hematopoietic stem cell transplantation is a curative-intent treatment for patients with high-risk hematologic diseases. However, interstitial pneumonitis (IP) and other toxicities remain major concerns after total body irradiation (TBI). We have proposed using linear accelerators with rice-bag compensators for intensity modulation (IM-TBI), as an alternative to the traditional cobalt-60 teletherapy with lung-shielding technique (Co-TBI).

Lumbosacral spine and marrow cavity modeling of acute hematologic toxicity in patients treated with intensity modulated radiation therapy for squamous cell carcinoma of the anal canal.

Purpose: To identify various dosimetric parameters of bone marrow cavity that correlate with acute hematologic toxicity (HT) in patients with anal squamous cell carcinoma treated with definitive chemoradiation therapy (CRT).

Methods And Materials: We analyzed 32 patients receiving CRT. The whole pelvic bone marrow (PBM) and the lumbosacral spine (LSS) subregion were contoured for each patient.

Superior liver sparing by combined coplanar/noncoplanar volumetric-modulated arc therapy for hepatocellular carcinoma: a planning and feasibility study.

Compared with step-and-shoot intensity-modulated radiotherapy (sIMRT) and tomotherapy, volumetric-modulated arc therapy (VMAT) allows additional arc configurations in treatment planning and noncoplanar (NC) delivery. This study was first to compare VMAT planning with sIMRT planning, and the second to evaluate the toxicity of coplanar (C)/NC-VMAT treatment in patients with hepatocellular carcinoma (HCC). Fifteen patients with HCC (7 with left-lobe and 8 with right-lobe tumors) were planned with C-VMAT, C/NC-VMAT, and sIMRT.

Early detection of Lewis lung carcinoma tumor control by irradiation using diffusion-weighted and dynamic contrast-enhanced MRI.

Purpose: To investigate the correlation between diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) derived parameters and radioresponsiveness of Lewis lung carcinoma (LLC) tumor.

Materials And Methods: LLC tumor growth in C57BL/6 mouse limb was used for the experiment. The tumors were irradiated with 10 Gy×5, or 30 Gy×2 vs.

Programmable segmented volumetric modulated arc therapy for respiratory coordination in pancreatic cancer.

We programmably divided long-arc volumetric modulated arc therapy (VMAT) into split short arcs, each taking less than 30s for respiratory coordination. The VMAT plans of five pancreatic cancer patients were modified; the short-arc plans had negligible dose differences and satisfied the 3%/3-mm gamma index on a MapCHECK-2 device.

Volumetric modulated arc therapy for nasopharyngeal carcinoma: a dosimetric comparison with TomoTherapy and step-and-shoot IMRT.

Purpose: Volumetric modulated arc therapy (VMAT), a novel technique, employs a linear accelerator to conduct dynamic modulation rotation radiotherapy. The goal of this study was to compare VMAT with helical tomotherapy (HT) and step-and-shoot intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) patients with regard to the sparing effect on organs at risk (OARs), dosimetric quality, and efficiency of delivery.

Materials And Methods: Twenty patients with NPC treated by HT were re-planned by VMAT (two arcs) and IMRT (7-9 fields) for dosimetric comparison.

Practically acquired and modified cone-beam computed tomography images for accurate dose calculation in head and neck cancer.

Background: On-line cone-beam computed tomography (CBCT) may be used to reconstruct the dose for geometric changes of patients and tumors during radiotherapy course. This study is to establish a practical method to modify the CBCT for accurate dose calculation in head and neck cancer.

Patients And Methods: Fan-beam CT (FBCT) and Elekta's CBCT were used to acquire images.

Treatment and dosimetric advantages between VMAT, IMRT, and helical tomotherapy in prostate cancer.

We investigated the possible treatment and dosimetric advantage of volumetric modulated arc therapy (VMAT) over step-and-shoot intensity-modulated radiation therapy (step-and-hhoot IMRT) and helical tomotherapy (HT). Twelve prostate cancer patients undergoing VMAT to the prostate were included. Three treatment plans (VMAT, step-and-shoot IMRT, HT) were generated for each patient.

Using cone-beam computed tomography to evaluate the impact of bladder filling status on target position in prostate radiotherapy.

Purpose: To assess bladder filling status and its impact on target position during daily intensity-modulated radiation therapy (IMRT) using cone-beam computed tomography (CBCT) in prostate cancer patients.

Patients And Methods: 23 patients with prostate cancer undergoing image-guided IMRT (78 Gy in 39 fractions) were included. On-board CBCT images were acquired daily and an endorectal balloon was placed daily.

Skin dose impact from vacuum immobilization device and carbon fiber couch in intensity modulated radiation therapy for prostate cancer.

To investigate the unexpected skin dose increase from intensity-modulated radiation therapy (IMRT) on vacuum cushions and carbon-fiber couches and then to modify the dosimetric plan accordingly. Eleven prostate cancer patients undergoing IMRT were treated in prone position with a vacuum cushion. Two under-couch beams scattered the radiation from the vacuum cushion and carbon-fiber couch.

Mathematical estimation and in vivo dose measurement for cone-beam computed tomography on prostate cancer patients.

Background And Purpose: Cone-beam computed tomography (CBCT) increases the doses on normal tissues. Our study sought to develop a mathematical model that would provide an estimate of and verify in vivo rectal dose from CBCT in prostate cancer patients.

Materials And Methods: Thermoluminescent dosimeters (TLDs) and Rando phantoms were used to measure doses to the pelvic region.

Association of clinical and dosimetric factors with postoperative pulmonary complications in esophageal cancer patients receiving intensity-modulated radiation therapy and concurrent chemotherapy followed by thoracic esophagectomy.

Background: To investigate the association between clinical/dosimetric factors and postoperative pulmonary complications (PPC) in esophageal cancer patients undergoing neoadjuvant chemotherapy and intensity-modulated radiation therapy (IMRT) followed by thoracic esophagectomy.

Methods: The data from 52 patients receiving combined modality treatment were analyzed. Chemotherapy was taxane-based in 43 and 5-fluorouracil-based in 9 patients.

Set-up errors due to endorectal balloon positioning in intensity modulated radiation therapy for prostate cancer.

Purpose: To investigate the set-up errors and deformation associated with daily placement of endorectal balloons in prostate radiotherapy.

Materials And Methods: Endorectal balloons were placed daily in 20 prostate cancer patients undergoing radiotherapy. Electronic portal images (EPIs) were collected weekly from anterior-posterior (AP) and lateral views.

Inclusion of biological factors in parallel-architecture normal-tissue complication probability model for radiation-induced liver disease.

Purpose: To include biologic factors in parallel-architecture normal-tissue complication probability (NTCP) model for radiation-induced liver disease (RILD) after three-dimensional conformal radiotherapy (3D-CRT) for gastric or hepatic cancer.

Methods And Materials: A total of 151 patients (89 with hepatocellular carcinoma and 62 with gastric cancer) who received 3D-CRT to the liver were included (isocenter dose range 33.0 to 66.

Biologic susceptibility of hepatocellular carcinoma patients treated with radiotherapy to radiation-induced liver disease.

Purpose: To identify the factors associated with radiation-induced liver disease (RILD) and to describe the difference in normal tissue complication probability (NTCP) between subgroups of hepatocellular carcinoma patients undergoing three-dimensional conformal radiotherapy (3D-CRT).

Methods And Materials: A total of 89 hepatocellular carcinoma patients who completed 3D-CRT for local hepatic tumors were included. The average isocenter dose was 49.

Unique role of proximal rectal dose in late rectal complications for patients with cervical cancer undergoing high-dose-rate intracavitary brachytherapy.

Purpose: To investigate the correlation of the radiation dose to the upper rectum, proximal to the International Commission of Radiation Units and Measurements (ICRU) rectal point, with late rectal complications in patients treated with external beam radiotherapy (EBRT) and high-dose-rate (HDR) intracavitary brachytherapy (ICRT) for carcinoma of the uterine cervix.

Methods And Materials: Between June 1997 and February 2001, 75 patients with cervical carcinoma completed definitive or preoperative RT and were retrospectively reviewed. Of the 75 patients, 62 with complete dosimetric data and a minimal follow-up of at least 1 year were included in this analysis.

Dosimetric analysis and comparison of three-dimensional conformal radiotherapy and intensity-modulated radiation therapy for patients with hepatocellular carcinoma and radiation-induced liver disease.

Purpose: This study compares the difference in dose-volume data between three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for patients with hepatocellular carcinoma (HCC) and previously documented radiation-induced liver disease (RILD) after 3D-CRT.

Materials And Methods: Between November 1993 and December 1999, 68 patients with HCC were treated with 3D-CRT at our institution. Twelve of them were diagnosed with RILD within 4 months of completion of 3D-CRT.

Radiation-induced liver disease after three-dimensional conformal radiotherapy for patients with hepatocellular carcinoma: dosimetric analysis and implication.

Purpose: To analyze the correlation of radiation-induced liver disease (RILD) with patient-related and treatment-related dose-volume factors and to describe the probability of RILD by a normal tissue complication probability (NTCP) model for patients with hepatocellular carcinoma (HCC) treated with three-dimensional conformal radiotherapy (3D-CRT).

Methods And Materials: Between November 1993 and December 1999, 93 patients with intrahepatic malignancies were treated with 3D-CRT at our institution. Sixty-eight patients who were diagnosed with HCC and had complete 3D dose-volume data were included in this study.

Radiation-induced liver disease after radiotherapy for hepatocellular carcinoma: clinical manifestation and dosimetric description.

Twelve patients with hepatocellular carcinoma and chronic hepatitis developed radiation-induced liver disease (RILD) after three-dimensional conformal radiotherapy. Six patients died of RILD and six recovered. Mean prescribed dose was 50.