18F-sodium fluoride positron emission tomography following coronary computed tomography angiography in predicting long-term coronary events: a 5-year follow-up study.

PURPOSE: The predictive value of 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) in combination with coronary computed tomography (CT) angiography (CCTA) for future coronary events has attracted interest. We evaluated the potential of 18F-NaF PET/CT following CCTA to predict major coronary events (MACE) during a 5-year follow-up period. METHODS: Forty patients with coronary atherosclerotic lesions detected on CCTA underwent 18F-NaF PET/CT examination. Each lesion was evaluated for luminal stenosis and high-risk plaque (HRP) with < 30 Hounsfield units and a > 1.1 remodeling index on CCTA. Focal 18F-NaF uptake in each lesion was quantified using the maximum tissue-to-background ratio (TBRmax), and the maximum TBRmax per patient (M-TBRmax) was determined. We followed MACE (cardiac death, acute coronary syndrome, and/or coronary revascularization > 6 months after 18F-NaF PET/CT) for 5 years. RESULTS: In total, 142 coronary lesions were analyzed. Eleven patients experienced any MACE. Patients with MACE showed a higher M-TBRmax than those without (1.40 ± .19 vs. 1.18 ± .18, P = .0011), and the optimal M-TBRmax cutoff to predict MACE was 1.29. Patients with M-TBRmax of ≥ 1.29 had a higher risk of MACE than those with lower values (P = .012, log-rank test), whereas patients with obstructive stenosis and those with HRP did not. Multivariate Cox proportional analysis adjusted for age, sex, coronary risk factors, and CCTA findings showed that M-TBRmax of ≥ 1.29 remained an independent predictor of 5-year MACE (hazard ratio, 5.4; 95% confidence interval, 1.1-25.4; P = .034). CONCLUSION: 18F-NaF PET/CT following CCTA provides useful strategies to predict 5-year MACE.

Fluorodeoxyglucose-positron emission tomography/computed tomography-positive ear lesions responsive to immunosuppressive therapy in a patient with otitis media with antineutrophil cytoplasmic antibody-associated vasculitis.

A 74-year-old woman presented with vertigo, left-beating nystagmus, and auditory disturbance 4 months prior, in whom a former physician suspected Meniere's disease. Her signs and symptoms mildly improved with a moderate dose of glucocorticoids, which was eventually tapered. Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) was performed 12 days prior to routine examination. Remarkable FDG uptake was observed in the surrounding areas of the bilateral Eustachian tubes and left middle ear, which was only partially detected on magnetic resonance imaging. The patient also tested positive for myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA). She was admitted to our hospital and diagnosed with otitis media with ANCA-associated vasculitis (OMAAV) based on the classification criteria. Four months after immunosuppressive therapy, the abnormal ear findings were not observed on follow-up FDG-PET/CT. The clinical course of this case suggests that FDG-PET/CT can detect occult ear involvement better than do other modalities in patients with OMAAV. In addition, FDG-PET/CT-positive ear lesions responded to immunosuppressive therapy. Therefore, FDG-PET/CT can help distinguish OMAAV from other ear diseases with non-inflammatory aetiologies and detect occult treatment-responsive OMAAV lesions in the clinical setting.

A longitudinal pilot study to assess temporal changes in coronary arterial 18F-sodium fluoride uptake.

PURPOSE: How coronary arterial 18F-sodium fluoride (18F-NaF) uptake on positron emission tomography changes over the long term and what clinical factors impact the changes remain unclear. We sought to investigate the topics in this study. METHODS: We retrospectively studied 15 patients with ≥1 coronary atherosclerotic lesion/s detected on cardiac computed tomography who underwent baseline and follow-up (interval of >3 years) 18F-NaF positron emission tomography/computed tomography scans. Focal 18F-NaF uptake in each lesion was quantified using maximum tissue-to-background ratio (TBRmax). The temporal change in TBRmax was assessed using a ratio of follow-up to baseline TBRmax (R-TBRmax). RESULTS: A total of 51 lesions were analyzed. Mean R-TBRmax was 0.96 ± 0.21. CT-based lesion features (location, obstructive stenosis, plaque types, features of high-risk plaque) did not correlate with an increase in R-TBRmax. In multivariate analysis, baseline TBRmax significantly correlated with higher follow-up TBRmax (ß = 0.57, P < 0.0001), and the presence of diabetes mellitus significantly correlated with both higher follow-up TBRmax (ß = 0.34, P = 0.001) and elevated R-TBRmax (ß = 0.40, P = 0.003). CONCLUSION: Higher coronary arterial 18F-NaF uptake is likely to remain continuously high. Diabetes mellitus affects the long-term increase in coronary arterial 18F-NaF uptake.

[Evaluation of Diffusional Kurtosis Inference Using Synthetic q-space Learning and Bias Correction].

PURPOSE: In synthetic q-space learning (synQSL), which uses deep learning to infer the diffusional kurtosis (K), a bias that depends on the noise level added to the synthetic training data occurs. The purpose of this study was to evaluate K inference using synQSL and bias correction. METHODS: Using the synthetic test data and the real image data, K was inferred by synQSL, and bias correction was performed. Then, those results were compared with K inferred by fitting by the least-squares fitting (LSF) method. At this time, the noise level of the training data was set to 3 types, the noise level of the synthesis test data was set to 5 types, and the number of excitation (NEX) of the real image data was set to 4 types. Robustness of inference was evaluated by the outlier rate, which is the ratio of K outliers to the whole brain. We also evaluated the root mean square error (RMSE) of the inferred K. RESULTS: The outlier rate inferred by synQSL without correction was significantly lower in the test data of each noise level than that by the LSF method and was further reduced by correction. In addition, the RMSE of NEX 1 with NEX 4 as the correct answer based on the real image data had the smallest correction result of K by synQSL. CONCLUSION: Inferring K using synQSL and bias correction is a robust and small error method compared to that using the LSF method.

Three-dimensional Winston-Lutz test using reusable polyvinyl alcohol-iodide (PVA-I) radiochromic gel dosimeter.

Medical linear-accelerator-based stereotactic radiosurgery (SRS) using a stereotactic apparatus or image-guided radiotherapy system for intracranial lesions is performed widely in clinical practice. In general, Winston-Lutz (WL) tests using films or electric portal imaging devices (EPIDs) have been performed as pre-treatment and routine quality assurance (QA) for the abovementioned treatment. Two-dimensional displacements between the radiation isocentre and mechanical isocentre are analysed from the test; therefore, it is difficult to identify the three-dimensional (3D) isocentre position intuitively. In this study, we developed an innovative 3D WL test for SRS-QA using a novel radiochromic gel dosimeter based on a polyvinyl alcohol-iodide (PVA-I) complex that can be reused after annealing. A WL gel phantom that was consisted of the PVA-I gel dosimeter poured into a tall acrylic container and an embedded small tungsten sphere was used as a position detector. A flatbed scanner was used to analyse the isocentre position. The measured 3D isocentre accuracy from the gel-based WL test was within 0.1 mm compared with that obtained from the EPID-based WL test. Furthermore, excellent reusability of the WL gel phantom was observed in long-term SRS isocentre verification, in which clinical SRS cases involving repeated irradiation and annealing were analysed. These results demonstrate the high accuracy and reliable evaluation of the isocentre position using an innovative test. In addition, the clinical-based routine SRS-QA using the PVA-I gel dosimeter demonstrates a highly convenience while affording an easy and fast analysis process.

Clinical implications of 18F-sodium fluoride uptake in subclinical aortic valve calcification: Its relation to coronary atherosclerosis and its predictive value.

BACKGROUND: Uptake of 18F-sodium fluoride (18F-NaF) on positron emission tomography (PET) reflects active calcification. Application of this technique in the early phase of aortic valve calcification (AVC) is of clinical interest. We investigated clinical implications of 18F-NaF uptake in subclinical AVC evaluated simultaneously with coronary atherosclerosis, and the utility of 18F-NaF uptake in predicting AVC progression. METHODS: We studied 25 patients with subclinical AVC and coronary plaques detected on computed tomography (CT) who underwent 18F-NaF PET/CT. AVC score, volume, mean density, and the presence of high-risk coronary plaque were evaluated on CT in each patient. Focal 18F-NaF uptake in AVC and in coronary plaques was quantified with the maximum tissue-to-background ratio (TBRmax). RESULTS: There were positive correlations between AVC TBRmax (A-TBRmax) and AVC parameters on CT. The 14 patients with high-risk coronary plaque had significantly higher A-TBRmax than those without such plaque (1.60 ± 0.18 vs 1.42 ± 0.13, respectively; P = 0.012). A-TBRmax positively correlated with maximum TBRmax of coronary plaque per patient (r = 0.55, P = 0.0043). In the 11 patients who underwent follow-up CT scan, A-TBRmax positively correlated with subsequent increase in AVC score (r = 0.74, P = 0.0091). CONCLUSION: Our 18F-NaF PET- and CT-based data indicate relationships between calcification activity in subclinical AVC and characteristics of coronary atherosclerosis. 18F-NaF PET may provide new information regarding molecular conditions and future progression of subclinical AVC.

Relationship between coronary arterial 18F-sodium fluoride uptake and epicardial adipose tissue analyzed using computed tomography.

PURPOSE: 18F-Sodium fluoride (18F-NaF) positron emission tomography (PET) has the potential to detect high-risk coronary plaques. Epicardial adipose tissue (EAT) reportedly correlates with coronary atherosclerosis progression. We evaluated the relationship between coronary arterial 18F-NaF uptake and EAT findings using computed tomography (CT). METHODS: We studied 40 patients with ≥ 1 coronary plaque detected on cardiac CT who underwent 18F-NaF PET/CT. EAT volume was measured using CT and indexed to body surface area in each patient. Each plaque was evaluated for CT-based luminal stenosis and high-risk features. The mean EAT density surrounding each plaque was calculated as perilesional EAT density (PLED) using non-contrast CT images. Focal 18F-NaF uptake in each plaque was quantified using the maximum tissue-to-background ratio (TBRmax). RESULTS: EAT volume index was similar between patients with TBRmax ≥ 1.28 (previously reported optimal cutoff to predict coronary events) and those with lower TBRmax, but patients with TBRmax ≥ 1.28 showed higher maximum PLED per patient (- 86 ± 12 Hounsfield units (HU) versus - 98 ± 11 HU, P = 0.0044). In the lesion-based analysis (n = 92), PLED was positively correlated with TBRmax, and the optimal PLED cutoff to identify TBRmax ≥ 1.28 was - 97 HU. On multivariate analysis adjusted for lesion location, obstructive stenosis, and high-risk plaque on CT, PLED ≥ - 97 HU remained a significant predictor of TBRmax ≥ 1.28. CONCLUSIONS: Increased PLED was associated with significant coronary arterial 18F-NaF uptake. Step-by-step analyses of EAT density on CT and coronary arterial 18F-NaF uptake on PET may offer novel strategies for risk prediction in coronary artery disease.

Effect of dose-delivery time for flattened and flattening filter-free photon beams based on microdosimetric kinetic model.

The effect of dose-delivery time with flattening filter (FF) and flattening filter-free (FFF) photon beams based on microdosimetric kinetic model (MKM) was investigated in this study. Monte Carlo simulation with the particle and heavy ion transport code system (PHITS) was performed to calculate the dose-mean lineal energy yD (keV/µm) of FF and FFF 6 MV photon beams using the IAEA phase-space files of Varian TrueBeam linear accelerator. Human non-small cell lung cancer NCI-H460 cells were used to determine the MKM parameters under the condition that dose-delivery times with continuous irradiation were 1, 5, 10, 30, and 60 min, and the adsorbed dose was 2, 4, and 8 Gy in this study. In addition, the relative biological effectiveness (RBE) of FF and FFF photon beams were calculated for evaluating the effect of dose delivery time. The RBE of FF decreased to 99.8% and 97.5% with 5 and 60 min for 2 Gy in comparison to 99.6% and 95.1% for 8 Gy, respectively. Meanwhile, that of FFF decreased to 99.5% and 94.9% with 5 and 60 min for 2 Gy in comparison to 99.5% and 94.9% for 8 Gy, respectively. Dose-delivery time has an effect on the RBE with photon beams. In other words, the dose-delivery time should be considered during radiation therapy. Furthermore, FFF photon beams were an effective irradiation method compared to FF in dose-delivery time on account of improving clinic throughput.

Predictive Value of 18F-Sodium Fluoride Positron Emission Tomography in Detecting High-Risk Coronary Artery Disease in Combination With Computed Tomography.

Background Application of 18F-sodium fluoride (18F-NaF) positron emission tomography ( PET ) to coronary artery disease has attracted interest. We investigated the utility of 18F-NaF uptake for predicting coronary events and evaluated the combined use of coronary computed tomography (CT) angiography ( CCTA ) and 18F-NaF PET /CT in coronary artery disease risk assessment. Methods and Results This study included patients with ≥1 coronary atherosclerotic lesion detected on CCTA who underwent 18F-NaF PET / CT . High-risk plaque on CCTA was defined as plaque with low density (<30 Hounsfield units) and high remodeling index (>1.1). Focal 18F-NaF uptake in each lesion was quantified using the maximum tissue:background ratio ( TBR max), and maximum TBR max per patient (M- TBR max) was determined. Thirty-two patients having a total of 112 analyzed lesions were followed for 2 years after 18F-NaF PET / CT scan, and 11 experienced coronary events (acute coronary syndrome and/or late coronary revascularization [after 3 months]). Patients with coronary events had higher M- TBR max than those without (1.39±0.18 versus 1.19±0.17, respectively; P=0.0034). The optimal M- TBR max cutoff to predict coronary events was 1.28 (area under curve: 0.79). Patients with M- TBR max ≥1.28 had a higher risk of earlier coronary events than those with lower M- TBR max ( P=0.0062 by log-rank test). In patient-based (n=41) and lesion-based (n=143) analyses of CCTA findings that predicted higher coronary 18F-NaF uptake, the presence of high-risk plaque was a significant predictor of both M- TBR max ≥1.28 and TBR max ≥1.28. Conclusions 18F-NaF PET / CT has the potential to detect high-risk coronary artery disease and individual coronary lesions and to predict future coronary events when combined with CCTA . Clinical Trial Registration URL : www.umin.ac.jp . Unique identifier: UMIN 000013735.

Successful radiotherapy for endometrial serous carcinoma with local repeated recurrence.

The incidence of endometrial serous carcinoma (ESC) has been increasing, and ESC is resistant to treatment. We report a patient with ESC who responded to radiotherapy for multiple recurrences. The first recurrence was detected in the vaginal wall and left internal iliac lymph node 5 months after the initial treatment. Concurrent chemoradiotherapy (CCRT) was administered. Radiation was delivered using the intensity modulated radiation therapy technique. The second recurrent tumor was detected in the right internal iliac lymph node after 4 months, and CCRT was conducted. After 4 months, the third recurrence was detected in the right common iliac node, and CCRT was performed. After 8 months, the fourth recurrence was detected in the horizontal portion of the duodenum, and radiotherapy was administered. After 9 months, the fifth recurrence was detected in the vaginal wall. Interstitial brachytherapy was conducted. Grade 2 gastrointestinal injury, nausea and radiodermatitis were observed. During the subsequent 13-month follow-up, there has been no recurrence. Although ESC is resistant to treatment, radiotherapy could be effective in some cases. Even when multiple recurrences occur, radiotherapy may be considered a treatment option if the irradiation level is permissible.

Effects of the Obesity Type on FDG-PET Image Quality.

PURPOSE: The aim of our study is to evaluate whether an 18F-FDG PET/CT image quality is influenced by the obesity type visceral fat or subcutaneous fat. METHODS: We chose continuously 68 patients with obesity (35 subcutaneous fats and 33 visceral fats) who underwent an 18F-FDG PET/CT scan at our clinic from January 3, 2015 to June 30, 2015. And then, we calculated the noise equivalent count (NECdensity), the signal to noise ratio of the liver (SNRliver), and the ratio of random coincidence counts to total prompt (random/prompt countrate) on each PET/CT image. RESULTS: We observed that NECdensity was decreased as the body mass index (BMI) and the abdominal circumference increased regardless of the obesity type. When the BMI was on the same degree between two types, however, NECdensity of a visceral fat was 21.6% that is inferior to that of subcutaneous fat on the average. A similar relation was satisfied also in abdominal circumference. Conversely, random/prompt countrate of a visceral fat was more than that of subcutaneous fat when the abdominal circumference and BMI were on the same degree, respectively. Overall, random/prompt countrate tended to increase as BMI and the abdominal circumference increased. With respect to SNRliver, the value of a visceral fat was inferior to that of subcutaneous fat unconditionally. CONCLUSION: When the BMI and abdominal circumference are on the same degree, respectively, the 18F-FDG PET/CT image quality of visceral fat is inferior to that of subcutaneous fat. The measure is to extend the collection time by about 20% in the pelvic area from the abdomen of visceral fat type obesity.

Data on analysis of coronary atherosclerosis on computed tomography and 18F-sodium fluoride positron emission tomography.

This article contains the data showing illustrative examples of plaque classification on coronary computed tomography angiography (CCTA) and measurement of 18F-sodium fluoride (18F-NaF) uptake in coronary atherosclerotic lesions on positron emission tomography (PET). We divided the lesions into one of three plaque types on CCTA (calcified plaque, non-calcified plaque, partially calcified plaque). Focal 18F-NaF uptake of each lesion was quantified using maximum tissue-to-background ratio. This article also provides a representative case with a non-calcified coronary plaque detected on CCTA and identified on 18F-NaF PET/non-contrast computed tomography based on a location of a vessel branch as a landmark. These complement the data reported by Kitagawa et al. (2017) [1].

18F-sodium fluoride positron emission tomography for molecular imaging of coronary atherosclerosis based on computed tomography analysis.

BACKGROUND AND AIMS: We aimed at evaluating the relation of 18F-sodium fluoride (18F-NaF) uptake on positron emission tomography (PET) to coronary atherosclerosis detected and assessed by computed tomography (CT). METHODS: Thirty-two patients with one or more coronary atherosclerotic lesions detected on cardiac CT underwent 18F-NaF PET/CT. Each coronary atherosclerotic lesion was evaluated on CT angiography for plaque types (calcified plaque [CP], non-calcified plaque [NCP], partially calcified plaque [PCP]), and the presence of CT-based high-risk features (minimum CT density <30 Hounsfield units and vascular remodeling index >1.1). Focal 18F-NaF uptake of each lesion was quantified using maximum tissue-to-background ratio (TBRmax). RESULTS: A total of 111 lesions were studied. In a patient-based analysis, logarithmically transformed coronary calcium score correlated positively with maximum TBRmax per patient, and 15 patients with myocardial infarction or unstable angina history showed a higher maximum TBRmax per patient than those without (1.36 ± 0.15 versus 1.15 ± 0.15, p = 0.0006). In a lesion-based analysis, PCP showed a higher TBRmax than CP and NCP (1.17 ± 0.19 versus 1.00 ± 0.24 and 0.92 ± 0.18, respectively, p < 0.0001), and the lesions with high-risk features had a higher TBRmax than those without (1.20 ± 0.21 versus 1.02 ± 0.20, p = 0.0011). CONCLUSIONS: Coronary arterial 18F-NaF uptake is related to total plaque burden, coronary event history, and specific features of coronary atherosclerosis based on CT analysis. 18F-NaF PET/CT, in combination with cardiac CT, may provide a new molecular imaging approach to identify high-risk patients and coronary atherosclerotic lesions.

[Evaluation of 3D Dose Distribution and Clinical Applications Using Polymer Gel Dosimeter].

Evaluation of dosimetric impact of the interplay effect between multi-leaf collimator (MLC) movement and tumor respiratory motion during volumetric modulated arc therapy (VMAT) delivery using polymer gel dosimeter was taken as an example in this article. An excellent gas barrier PAN (polyacrylonitrile) bottle filled with polyacrylamide-based gel dosimeter contained magnesium chloride as a sensitizer (iPAGAT dosimeter) was set to the QUASAR™ respiratory motion phantom (Modus), and was moved with motion amplitudes (peak-to-peak amplitude) of 1 and 2 cm with a 4 second period during VMAT delivery by the Novalis Tx linear accelerator (Varian/BrainLAB). Two spherical GTVs with 2 cm diameter and two PTVs were defined considering the respiratory motion and setup uncertainties. Three-dimensional (3D) dose distribution in iPAGAT dosimeter was read out by the 3T MRI system, and was evaluated by the dose profiles, gamma analysis and the dose-volume histogram (DVH) using in-house developed software. As a result, interplay effect was negligible since dose coverage of GTV was sufficient during VMAT delivery with simulated respiratory motion.

Effects of Non-radioactive Material around Radioactive Material on PET Image Quality.

PURPOSE: Subcutaneous fat is a non-radioactive material surrounding the radioactive material. We developed a phantom, and examined the effect of subcutaneous fat on PET image quality. METHODS: We created a cylindrical nonradioactive mimic of subcutaneous fat, placed it around a cylindrical phantom in up to three layers with each layer having a thickness of 20 mm to reproduce the obesity caused by subcutaneous fat. In the cylindrical phantom, hot spheres and cold spheres were arranged. The radioactivity concentration ratio between the hot spheres and B.G. was 4:1. The radioactivity concentration of B.G. was changed as follows: 1.33, 2.65, 4.00, and 5.30 kBq/mL. 3D-PET images were collected during 10 minutes. RESULTS: When the thickness of the mimicked subcutaneous fat increased from 0 mm to 60 mm, noise equivalent count decreased by 58.9‒60.9% at each radioactivity concentration. On the other hand, the percentage of background variability increased 2.2‒5.2 times. Mimic subcutaneous fat did not decrease the percentage contrast of the hot spheres, and did not affect the cold spheres. CONCLUSION: Subcutaneous fat decreases the noise equivalent count and increases the percentage of background variability, which degrades PET image quality.

Diagnostic Performance of Positron Emission Tomography for the Presurgical Evaluation of Patients with Non-lesional Intractable Partial Epilepsy: Comparison among 18F-FDG, 11C-Flumazenil, and 11C-Flumazenil Binding Potential Imaging Using Statistical Imaging Analysis.

To compare the diagnostic performance of 18F-FDG PET, 11C-FMZ PET, and 11C-FMZ BP imaging for the evaluation of patients with intractable partial epilepsy whose MRI findings are normal by using statistical imaging analysis. Ten patients underwent comprehensive presurgical evaluation, including PET studies, to assess the epileptic foci. The extent of cortical resection was based on the results of intracranial video-electroencephalography (IVEEG) monitoring and brain mapping under stimulation. The images of 10 patients and 30 controls were spatially normalized to templates generated in-house by non-rigid registration and the standardized images of the patients and controls were statistically compared. Epileptic focus candidates were visualized on a color map of axial images of each template and the focus site was identified in candidates for lobar location. In patients with Engel I postoperative seizure outcomes we assessed the sensitivity and specificity of the imaging methods for lobar focus localization. We also compared the concordance scores of patients with Engel I and Engel II-IV postoperative seizures. The sensitivity and specificity for lobar focus localization on 18F-FDG PET scans was 90.0% and 84.8%, respectively; it was 30.0% and 81.4% for 11C-FMZ PET, 40.0% and 66.7% for 11C-FMZ BP images, and 100.0% and 51.4% for 18F-FDG PET/11C-FMZ PET/11C-FMZ BP images. In one patient the epileptic focus not detected on 18F-FDG PET scans was shown on 11C-FMZ BP images. In patients with Engel I post-treatment seizures the concordance scores were significantly higher for 18F-FDG PET than 11C-FMZ PET and 11C-FMZ BP images (p < 0.05). With respect to sensitivity and specificity, 18F-FDG PET was superior to 11C-FMZ PET and 11C-FMZ BP imaging. However, in some patients with normal MRI results, 11C-FMZ BP studies may complement 18F-FDG PET findings in efforts to identify the epileptogenic lobar regions.

[An examination of the utility of high-precise radiation therapies for the recurrence of postoperative esophageal cancer].

We analyzed 16 cases (23 therapeutic sites) of post-operative recurrence of esophageal cancers that were treated with high-precise radiation therapies.The recurrence sites were cervical lymph nodes (5 cases), superior mediastinal lymph nodes (5 cases), posterior mediastinal lymph nodes (3 cases), regional lymph nodes with anastomosis (2 cases), abdominal paraaortic lymph node (3 cases), and regions with hematogenous metastasis (5 cases: liver, lung, spleen, and dissemination to the diaphragm bottom).By recurrence number, 10 cases presented with a single lesion, and 6 cases had multiple lesions.The effect of the treatment was complete response (CR) in all cases, and 6 cases maintained CR.The median of the overall survival after radiotherapy was 562 (132-1,231) days.Analysis of the prognostic factors for the overall survival from a recurrence revealed that the metastatic number (single) (p=0.003), and the metastatic pattern(hematogenous metastasis) (p= 0.004), significantly improved prognosis.We conclude that radiotherapy is an option to extend prognosis in some recurrence cases.

Effect of lapatinib on hepatic parenchymal enhancement on gadoxetate disodium (EOB)-enhanced MRI scans of the rat liver.

PURPOSE: The purpose of this study was to investigate the effect of lapatinib treatment on hepatic parenchymal enhancement on Gd-EOB-MRI scans in rat. MATERIALS AND METHODS: Institutional animal review board approval was received prior to the commencement of all studies. Five rats received a single oral dose of 100 mg/kg/day lapatinib for 7 consecutive days. The controls (n = 5) were given 0.5 % (w/v) aqueous hydroxypropyl methyl cellulose containing 0.1 % (v/v) Tween 80 for 7 days. After the acquisition of gadoxetate disodium-enhanced MR images using 0.025 mmol gadolinium/kg, their livers were subjected to pathologic study to determine the expression level of organic anion-transporting polypeptide 1 (oatp1) and multi-drug resistance-associated protein 2 (mrp2). RESULTS: Relative enhancement of the liver was similar in both groups. At the hepatobiliary phase, which in rats occurs 3 min after the injection of Gd-EOB, it was 0.90 ± 0.06 in lapatinib-treated rats and 0.84 ± 0.08 in the controls (p = 0.30). There was also no difference in the expression level of oatp1 and mrp2. CONCLUSION: In rats, the administration of lapatinib for 7 days had no effect on hepatic parenchymal enhancement on Gd-EOB-MRI scans.

[Comparison of setup accuracy between ExacTrac X-ray 6 dimensions and cone-beam computed tomography for intracranial and pelvic image-guided radiotherapy].

The aim of this study was to compare the setup difference measured with ExacTrac X-ray 6D (ETX6D) and cone-beam computed tomography (CBCT) for non-invasive fractionated radiotherapy. Setup data were collected on a Novalis Tx treatment unit for both a head phantom and patients with intracranial tumors and a pelvic phantom and patients with prostate cancer. Initially, setup was done for a phantom using ETX6D. Secondly, a treatment couch was shifted or rotated by each already known value. Thirdly, ETX6D and CBCT scans were obtained. Finally, setup difference was determined: the registrations of ETX6D images with the corresponding digitally reconstructed radiographs using ETX6D fusion, and registrations of CBCT images with the planning CT using online 6D fusion. The setup difference between ETX6D and CBCT was compared. The impact of shifts and rotations on the difference was evaluated. Patients' setup data was similarly analyzed. In phantom experiments, the root mean square (RMS) of difference of the shift and rotation was less than 0.45 mm for translations, and 0.17 degrees for rotations. In intracranial patients' data, the RMS of that was 0.55 mm and 0.44 degree, respectively. In prostate cancer patients' data, the RMS of that was 0.77 mm and 0.79 degree, respectively. In this study, we observed modest setup differences between ETX6D and CBCT. These differences were generally less than 1.00 mm for translations, and 1.00 degrees for rotations, respectively.

[Influence of high-definition multileaf collimator for three-dimensional conformal radiotherapy and intensity-modulated radiotherapy of prostate cancer].

The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber. The dosimetric impact of treatment planning for 3DCRT and IMRT of prostate cancer for ten clinical cases using two MLC systems was evaluated quantitatively. 3DCRT was divided to 3DCRT(middle) as fitting at middle of leaf tip and 3DCRT(outside) as fitting at outside of leaf tip. The leaf transmission factor and DLG of HD120 MLC for 6 and 10 MV X-ray decreased by 0.2% and 1 mm, respectively, compared to M120 MLC. The mean conformity index of PTV of treatment planning for prostate 3DCRT(middle), 3DCRT(outside) , and IMRT decreased by 0.9%, 6.6%, and 0.9% and the mean homogeneity index increased 2.3%, 13.0%, and 4.2%, respectively. The mean V20, V40, and V65 decreased by 2.4%, 6.6%, and 4.5% for bladder and 3.3%, 6.1%, and 5.9% for rectum, respectively. The results of this work demonstrated that the dose conformity of PTV improved and the dose of bladder and rectum decreased for 3DCRT and IMRT of prostate cancer using HD120 MLC compared to M120 MLC, because of reduction of leaf width, leaf transmission, and rounded leaf end transmission.