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Masayuki Matsuo,
Kazuhiro Miwa, Osamu Tanaka,
Jun Shinoda,
Hironori Nishibori,
Yusuke Tsuge,
Hirohito Yano,
Toru Iwama,
Shinya Hayashi,
Hiroaki Hoshi,
Jitsuhiro Yamada,
Masayuki Kanematsu,
Hidefumi Aoyama
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ABSTRACT: The purpose of this work was to define the optimal margins for gadolinium-enhanced T(1)-weighted magnetic resonance imaging (Gd-MRI) and T(2)-weighted MRI (T(2)-MRI) for delineating target volumes in planning radiation therapy for postoperative patients with newly diagnosed glioblastoma multiforme (GBM) by comparison to carbon-11-labeled methionine positron emission tomography ([(11)C]MET-PET) findings.
Computed tomography (CT), MRI, and [(11)C]MET-PET were separately performed for radiation therapy planning for 32 patients newly diagnosed with GBM within 2 weeks after undergoing surgery. The extent of Gd-MRI (Gd-enhanced clinical target volume [CTV-Gd]) uptake and that of T(2)-MRI of the CTV (CTV-T(2)) were compared with the extent of [(11)C]MET-PET (CTV--[(11)C]MET-PET) uptake by using CT--MRI or CT--[(11)C]MET-PET fusion imaging. We defined CTV-Gd (x mm) and CTV-T(2) (x mm) as the x-mm margins (where x = 0, 2, 5, 10, and 20 mm) outside the CTV-Gd and the CTV-T(2), respectively. We evaluated the relationship between CTV-Gd (x mm) and CTV-- [(11)C]MET-PET and the relationship between CTV-T(2) (x mm) and CTV-- [(11)C]MET-PET.
The sensitivity of CTV-Gd (20 mm) (86.4%) was significantly higher than that of the other CTV-Gd. The sensitivity of CTV-T(2) (20 mm) (96.4%) was significantly higher than that of the other CTV-T(2) (x = 0, 2, 5, 10 mm). The highest sensitivity and lowest specificity was found with CTV-T(2) (x = 20 mm).
It is necessary to use a margin of at least 2 cm for CTV-T(2) for the initial target planning of radiation therapy. However, there is a limit to this setting in defining the optimal margin for Gd-MRI and T(2)-MRI for the precise delineation of target volumes in radiation therapy planning for postoperative patients with GBM.
International journal of radiation oncology, biology, physics 11/2010; 82(1):83-9. · 4.59 Impact Factor
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ABSTRACT: The purpose of our study was to evaluate the usefulness of diffusion-weighted imaging in predicting the responses to neoadjuvant therapy for head and neck squamous cell carcinomas. Diffusion-weighted, T2-weighted, and gadolinium-enhanced T1-weighted images were obtained from 28 patients with untreated head and neck squamous cell carcinomas with histological proof. A blinded radiologist evaluated the quantitative and qualitative signal intensities and apparent diffusion coefficients (ADCs) in the lesions on each sequence. All patients were treated by neoadjuvant therapies, and the post-therapeutic tumor regression rate was determined. Both the quantitative and qualitative signal intensities on diffusion-weighted images showed positive correlations (r = 0.367 and 0.412, p < .05), and the ADCs showed a weak, inversed correlation (r = -0.384, p < .05) with the tumor regression rates. Diffusion-weighted imaging including an assessment by ADCs may be able to predict tumor response to neoadjuvant therapy for head and neck squamous cell carcinomas.
European Radiology 01/2009; 19(1):103-9. · 3.22 Impact Factor
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ABSTRACT: To compare the dosimetric results between MRI-based and TRUS-based preplanning in permanent prostate brachytherapy, and to estimate the accuracy of MRI-based preplanning by comparing with CT/MRI fusion-based postimplant dosimetry.
Twenty-one patients were entered in this prospective study with written informed consent. MRI-based and TRUS-based preplanning were performed. The seed and needle locations were identical according to MRI-based and TRUS-based preplanning. MRI-based and TRUS-based preplanning were compared using DVH-related parameters. Following brachytherapy, the accuracy of the MRI-based preplanning was evaluated by comparing it with CT/MRI fusion-based postimplant dosimetry.
Mean MRI-based prostate volume was slightly underestimated (0.73 cc in mean volume) in comparison to TRUS-based volume. There were no significant differences in the mean DVH-related parameters except with rectal V(100)(cc) between TRUS-based and MRI-based preplanning. Mean rectal V(100)(cc) was 0.74 cc in TRUS-based and 0.29 cc in MRI-based preplanning, respectively, and the values demonstrated a statistical difference. There was no statistical difference in mean rectal V(150)(cc), and rectal V(100)(cc) between MRI-based preplanning and CT/MRI fusion-based postimplant dosimetry.
Prostate volume estimation and DVH-related parameters in MRI-based preplanning were almost identical to TRUS-based preplanning. From the results of CT/MRI fusion-based postimplant dosimetry, MRI-based preplanning was therefore found to be a reliable and useful modality, as well as being helpful for TRUS-based preplanning. MRI-based preplanning can more accurately predict postimplant rectal dose than TRUS-based preplanning.
Radiotherapy and Oncology 08/2008; 88(1):115-20. · 5.58 Impact Factor
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ABSTRACT: Two-thirds of patients with a gray-zone prostate-specific antigen (PSA) level undergo unnecessary biopsy. Sensitivity is not yet sufficient to permit the use of modified PSA parameters or magnetic resonance (MR) imaging alone for prostate cancer screening. Thus, we evaluated the combination of MR imaging and PSA density (PSAD) for specificity and sensitivity.
During the period April 2004 through March 2006, 185 patients with a PSA level of 4.0-10.0 ng/mL underwent MR imaging and transrectal ultrasonography-guided 8-core biopsy (systemic sextant biopsy of the peripheral zone plus two cores of transition zone). All MR images were interpreted prospectively by two radiologists. An image was considered positive for prostate cancer if any feature indicated a cancerous lesion. Receiver operating characteristic (ROC) curves were used to compare the usefulness of the PSA level, PSAD and PSA transitional zone density (PSATZ) for the detection of prostate cancer.
Of the 185 patients, 62 had prostate cancer. Sensitivity and specificity of the axial T2-weighted MR imaging findings for cancer detection were 79.0% and 59.4%, respectively. The area under the ROC curve was 0.590 for the PSA level, 0.718 for PSAD and 0.695 for PSATZ. MR imaging findings and PSAD were shown by multivariate analysis to be statistically significant independent predictors of prostate cancer (P < 0.001). With a PSAD cut-off value of 0.111, sensitivity was 96.8%, but specificity was 19.5%. Combining MR imaging findings with PSAD increased the specificity to 40% and retained 95% sensitivity.
MR imaging findings combined with PSAD provide high sensitivity and improve the specificity for the early detection of prostate cancer.
International Journal of Urology 05/2008; 15(4):322-6; discussion 327. · 1.75 Impact Factor
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ABSTRACT: To investigate the time course of prostatic edema and the effect on the dose-volume histograms of the prostate for patients treated with brachytherapy.
A total of 74 patients with prostate cancer were enrolled in this prospective study. A transrectal ultrasound-based preplan was performed 4 weeks before implantation and computed tomography/magnetic resonance imaging fusion-based postimplant dosimetry was performed on the day after implantation (Day 1) and 30 days after implantation (Day 30). The prostate volume, prostate volume covered by 100% of the prescription dose (V100), and dose covering 90% of the prostate (D90) were evaluated with prostatic edema over time.
Prostatic edema was greatest on Day 1, with the mean prostate volume 36% greater than the preplan transrectal ultrasound-based volume; it thereafter decreased over time. It was 9% greater than preplan volume on Day 30. The V(100) increased 5.7% from Day 1 to Day 30, and the D90 increased 13.1% from Day 1 to Day 30. The edema ratio (postplan/preplan) on Day 1 of low-quality implants with a V(100) of <80% was significantly greater than that of intermediate- to high-quality implants (>80% V100; p = 0.0272). The lower V100 on Day 1 showed a greater increase from Day 1 to Day 30. A V100 on Day 1 of >92% is unlikely to increase >0% during the interval studied.
Low-quality implants on Day 1 were highly associated with edema; however, such a low-quality implant on Day 1, with significant edema, tended to improve by Day 30. If a high-quality implant (V100 >92%) can be obtained on Day 1, a re-examination is no longer necessary.
International Journal of Radiation OncologyBiologyPhysics 10/2007; 69(2):614-8. · 4.11 Impact Factor
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ABSTRACT: No studies have yet evaluated the effects of a dosimetric analysis for different urethral volumes. We therefore evaluated the effects of a dosimetric analysis to determine the different urethral volumes.
This study was based on computed tomography/magnetic resonance imaging (CT/MRI) combined findings in 30 patients who had undergone prostate brachytherapy. Postimplant CT/MRI scans were performed 30 days after the implant. The urethra was contoured based on its diameter (8, 6, 4, 2, and 0 mm). The total urethral volume-in cubic centimeters [UrV150/200(cc)] and percent (UrV150%/200%), of the urethra receiving 150% or 200% of the prescribed dose-and the doses (UrD90/30/5) in Grays to 90%, 30%, and 5% of the urethral volume were measured based on the urethral diameters.
The UrV150(cc) and UrD30 were statistically different between the of 8-, 6-, 4-, 2-, and 0-mm diameters, whereas the UrD5 was statistically different only between the 8-, 6-, and 4-mm diameters. Especially for UrD5, there was an approximately 40-Gy difference between the mean values for the 8- and 0-mm diameters.
We recommend that the urethra should be contoured as a 4- to 6-mm diameter circle or one side of a triangle of 5-7 mm. By standardizing the urethral diameter, the urethral dose will be less affected by the total urethral volume.
Radiation Medicine 09/2007; 25(7):329-34.
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ABSTRACT: The goals of this study were (1) to compare, in a single institute, the clinical results of patients with newly diagnosed glioblastoma multiforme (GBM) treated with stereotactic radiosurgery (SRS), which has been incorporated into the initial management approach, with those in-patients treated with intra-operative radiotherapy (IORT) and (2) to assess whether these local irradiation boost therapies are prognostic factors on survival analysis. One hundred and twenty adult patients with supratentorial GBM had undergone tumour resection or biopsy and had received external beam radiotherapy (EBRT). Of them, 31 underwent IORT, 29 underwent SRS, and the remaining 60 had no local high-dose irradiation boost. The local irradiation boost led to clearly better results on survival of GBM patients. Furthermore, SRS is less invasive and allows for meticulous target planning of the irradiation boost, and was superior to IORT in terms of survival prolongation as well as suppression of local tumour recurrence/progression at the primary site in this series. In addition, SRS was a significant, positive prognostic factor for survival as well as gross-total resection of the tumour, and could be an alternative therapeutic modality to IORT for GBM.
Journal of Radiotherapy in Practice 08/2007; 6(03):143 - 152.
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ABSTRACT: The aim of this study was to compare the outcomes between 1-mm and 5-mm section computed tomography (CT)-based postimplant dosimetry.
A series of 21 consecutive patients underwent permanent prostate brachytherapy. The postimplant prostate volume was calculated using 1-mm and 5-mm section CT. One radiation oncologist contoured the prostate on CT images to obtain the reconstructed prostate volume (pVol), prostate V(100) (percent of the prostate volume receiving at least the full prescribed dose), and prostate D(90) (mean dose delivered to 90% of the prostate gland). The same radiation oncologist performed the contouring three times to evaluate intraobserver variation and subjectively scored the quality of the CT images.
The mean +/-1 SD postimplant pVol was 20.17 +/- 6.66 cc by 1-mm section CT and 22.24 +/- 8.48 cc by 5-mm section CT; the difference in the mean values was 2.06 cc (P < 0.01). The mean postimplant prostate V(100) was 80.44% +/- 7.06% by 1-mm section CT and 77.33% +/- 10.22% by 5-mm section CT. The mean postimplant prostate D(90) was 83.28% +/- 10.81% by 1-mm section CT and 78.60% +/- 15.75% by 5-mm section CT. In the evaluation of image quality, 5-mm section CT was assigned significantly higher scores than 1-mm section CT. In regard to intraobserver variation, 5-mm section CT revealed less intraobserver variation than 1-mm section CT.
Our current results suggested that the outcomes of postimplant dosimetry using 1-mm section CT did not improved the results over those obtained using 5-mm section CT in terms of the quality of the CT image or reproducibility.
Radiation Medicine 02/2007; 25(1):22-6.
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ABSTRACT: To compare the CT-based and CT/MRI fusion-based postimplant dosimetry after permanent prostate brachytherapy and to evaluate the improvement in CT-based dosimetry by physicians with or without experience in using the CT/MRI fusion method.
Thirty-eight consecutive patients agreed to participate in a prospective study. The prostate contours from CT/MRI fusion are the gold standard for determining the prostate volume and dose volume histogram (DVH). CT-based postimplant dosimetries were performed by two physicians. Observer 1 was a radiologist who had never used CT/MRI fusion method for postimplant dosimetric analysis. Observer 2 was a radiation oncologist experienced in postimplant analysis using the CT/MRI fusion method. The prostate dosimetry was evaluated by prostate D90 and V100.
No significant difference was observed in the mean prostate volumes between the two observers and the CT/MRI fusion data. However, the correlation coefficient value for observer 2 (R(2)=0.932) was greater than that for observer 1 (R(2)=0.793). The D90 and V100 values as evaluated by the two observers were significantly underestimated in comparison to those evaluated using the CT/MRI fusion methods. The DVH related parameters were underestimated more frequently by observer 1 than by observer 2: (prostate D90: 99.56% for observer 1, 102.97% for observer 2, 109.37% for CT/MRI fusion. Prostate V100: 88.12% for observer 1, 90.14% for observer 2, 91.91% for CT/MRI fusion).
The difference in the mean value in D90 and V100 by observer 1 was significantly greater than that for observer 2. These findings suggest that the CT/MRI fusion method provides accurate feedback which thereby improves CT-based postimplant dosimetry for prostate brachytherapy.
Radiotherapy and Oncology 01/2007; 81(3):303-8. · 5.58 Impact Factor
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ABSTRACT: The aim of this study was to compare the outcomes between magnetic resonance imaging (MRI)-based and computed tomography (CT)/MRI fusion-based postimplant dosimetry methods in permanent prostate brachytherapy.
Between October 2004 and March 2006, a total of 52 consecutive patients with prostate cancer were treated by brachytherapy, and postimplant dosimetry was performed using CT/MRI fusion. The accuracy and reproducibility were prospectively compared between MRI-based dosimetry and CT/MRI fusion-based dosimetry based on the dose-volume histogram (DVH) related parameters as recommended by the American Brachytherapy Society.
The prostate volume was 15.97+/-6.17 cc (mean+/-SD) in MRI-based dosimetry, and 15.97+/-6.02 cc in CT/MRI fusion-based dosimetry without statistical difference. The prostate V100 was 94.5% and 93.0% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p=0.002). The prostate D90 was 119.4% and 114.4% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p=0.004).
Our current results suggested that, as with fusion images, MR images allowed accurate contouring of the organs, but they tended to overestimate the analysis of postimplant dosimetry in comparison to CT/MRI fusion images. Although this MRI-based dosimetric discrepancy was negligible, MRI-based dosimetry was acceptable and reproducible in comparison to CT-based dosimetry, because the difference between MRI-based and CT/MRI fusion-based results was smaller than that between CT-based and CT/MRI fusion-based results as previously reported.
International Journal of Radiation OncologyBiologyPhysics 11/2006; 66(2):597-602. · 4.11 Impact Factor
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ABSTRACT: Castleman's disease is an usually benign lymphoid tumor of uncertain etiology that generally appears as a solitary mediastinal mass. We present a case of Castleman's disease in the right chest wall of a 60-year-old woman. Magnetic resonance imaging showed a well-defined, oval mass that was early enhanced on T1-weighted images. The mass was diagnosed by percutaneous core needle biopsy with computed tomography guidance. The patient has remained well for 5 years without an increase in tumor size. We also summarize the international literature.
Radiation Medicine 09/2006; 24(7):529-33.
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ABSTRACT: Various histologic types of neurogenic tumors may originate in the mediastinum and chest wall. It is possible to make accurate diagnosis of these tumors by using the multiplanar capability and high contrast resolution of MR imaging because of these characteristic imaging findings. MR and histologic features of these tumors are illustrated and described in this essay.
Journal of Thoracic Imaging 12/2005; 20(4):316-20. · 0.98 Impact Factor
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ABSTRACT: A 65-year-old man with multiple hepatocellular carcinomas in the liver with type C viral hepatitis had a solitary mediastinal lymph node metastasis in the right paratracheal to tracheobronchial region. Surgical resection for the mediastinal metastasis was undertaken based on magnetic resonance (MR) imaging findings, suggesting its radicality. We assess the MR imaging findings and presumable pathways of lymphatic metastasis from the liver to mediastinal lymph nodes in this report.
Magnetic Resonance Imaging 02/2005; 23(1):111-4. · 1.99 Impact Factor
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ABSTRACT: The widespread use of chest CT has increased the detection of small nodules in lung, and intrapulmonary lymph nodes are identified frequently among them. We report a case of intrapulmonary lymph node mimicking a pulmonary metastasis associated with adenocarcinoma. The patient was a 60-year old woman with a small nodule that was round shaped and existed subpleural portion of left upper lobe distant from primary adenocarcinoma. She underwent surgery, and histological examination of resected material revealed that the small nodule was composed of lymph node without malignant cell. Intrapulmonary lymph nodes (IPLN) should be included in the differential diagnosis of small nodules in the peripheral lung field.
European Journal of Radiology Extra.
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ABSTRACT: We report two cases of seed migration to the vertebral venous plexus after iodine-125 (I-125) transperineal interstitial permanent prostate brachytherapy.
Case 1: A 67-year-old Japanese man underwent percutaneous transperineal interstitial permanent prostate brachytherapy at our institution. Three months after brachytherapy, routine followup kidney-urinary bladder (KUB) radiography showed two seeds that had migrated to the pelvic area and were overlapped by sacral bone. It was very difficult to detect the seeds by visceral CT, because seeds were in contact with to vertebral bone, and seeds and bone were of the same CT value in visceral CT. But bone CT could distinguish seeds and bone, and it showed seed migration to the vertebral venous plexus in the sacral vertebral canal. Case 2: A 75-year-old Japanese man underwent percutaneous transperineal interstitial permanent prostate brachytherapy at our institution. The day after seed implantation, routine followup KUB radiography showed that a seed had migrated to the pelvic area and was overlapped by sacral bone. Bone CT clearly showed seed migration to the vertebral venous plexus in the vertebral canal in comparison with visceral CT.
Seeds that have migrated to the vertebral venous plexus are difficult to be detected by visceral CT or KUB radiography. In visceral CT, it is difficult to distinguish seed and bone, especially when they are touching each other because they have the same CT value in visceral CT. It is therefore necessary to perform bone CT to detect such migrating seeds.
To our knowledge, this is the first report of seed migration to the vertebral venous plexus after prostate brachytherapy. We thought that seeds migrate to the vertebral plexus via the pelvic venous pathway. If seed migration to the pelvic area and the overlapped sacral bone area is found after brachytherapy, bone CT should be performed, especially when it is difficult to detect the seed in visceral CT.
Brachytherapy 5(2):127-30. · 1.47 Impact Factor
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Masayuki Matsuo,
Masahiro Nakano,
Shinya Hayashi,
Satoshi Ishihara,
Sunaho Maeda,
Hiromi Uno, Osamu Tanaka,
Masayuki Kanematsu,
Takashi Deguchi,
Hiroaki Hoshi,
Takuma Aoyama,
Hisayoshi Fujiwara
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ABSTRACT: Transperineal interstitial prostate brachytherapy is increasingly used as a definitive treatment for early prostate cancer. After this treatment, seed migration to the heart is rarely frequently observed. The patient was experienced seed migration to the right ventricle after the treatment, it was difficult to diagnose in posteroanterior chest radiograph, but we were able to demonstrate it in multi-detector row computed tomography (MDCT).
European Journal of Radiology Extra 61(3):91-93.
