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Hidefumi Aoyama

Publications and source records attributed to Hidefumi Aoyama.

10 recordsLinked to original sources
PubMed2003

Hypofractionated stereotactic radiotherapy alone without whole-brain irradiation for patients with solitary and oligo brain metastasis using noninvasive fixation of the skull.

PURPOSE: To evaluate the efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) using noninvasive fixation of the skull on solitary or oligo brain metastatic patients as an alternative to stereotactic radiosurgery (SRS) using invasive fixation. PATIENTS AND METHODS: The subjects were 87 patients who had 4 or fewer brain metastases (50 solitary, 37 oligometastases). Treatment was conducted on 159 metastases by using a linac-based stereotactic system. The median isocentric dose was 35 Gy in 4 fractions. Whole-brain irradiation was not applied as an initial treatment. For the salvage treatment of metachronous brain metastases, repeat HSRT or whole-brain irradiation was applied. RESULTS: The actuarial 1-year local tumor control rate was 81%. Treatment-related complications were observed in 4 patients in the early period (<3 months) and in 2 patients in the late period. The median survival period was 8.7 months. Metachronous brain metastases occurred in 30 patients, and none of the 18 patients who were eligible for salvage HSRT refused to receive it again. CONCLUSIONS: Hypofractionated stereotactic radiotherapy achieved tumor control and survival equivalent to those of SRS reported in the literature. The results suggested that HSRT could be an alternative for solitary or oligo brain metastatic patients with less toxicity and less invasiveness compared to SRS.

Actuarial Analysis↗
PubMed2003

Visualization of the corticospinal tract pathway using magnetic resonance axonography and magnetoencephalography for stereotactic irradiation planning of arteriovenous malformations.

Corticospinal tract (CST) information using anisotropic diffusion-weighted imaging and magnetoencephalography were integrated into radiosurgical planning for two patients with deeply seated arteriovenous malformation. The volume of CST receiving >10 Gy, >15 Gy, and maximum dose of CST could be reduced when plans were created with the aid of CST information compared with plans without the information. The results indicate that the use of CST information might reduce the risk of post-radiosurgical motor disturbance resulting from radiation necrosis.

Arteriovenous Malformations↗
PubMed2003

Cervical and intracranial atherosclerosis and silent brain infarction in Japanese patients with coronary artery disease.

PURPOSE: To investigate the prevalence of cervical and intracranial atherosclerosis and silent brain infarction in patients with coronary artery disease (CAD). METHODS: Cervical and intracranial atherosclerotic lesions on magnetic resonance angiography (MRA) and silent brain infarctions on magnetic resonance imaging (MRI) were investigated in comparison with the findings of coronary angiography in 133 consecutive patients with CAD. RESULTS: The mean severity scores of cervical and intracranial MRA lesions were significantly higher in the three-vessel CAD (0.40 and 0.53, respectively) than in the zero-vessel CAD group (0.04 and 0.11). The mean scores of the maximal size and multiplicity of MRI lesion were also significantly greater in the two-vessel (1.00 and 1.44) and three-vessel CAD (0.94 and 1.26) than in the zero-vessel CAD group (0.27 and 0.50). The incidence of MRA lesion was markedly higher in patients with brain MRI lesion than in those without (51.1 vs. 6.5%). CONCLUSIONS: Serious coronary artery lesions were commonly accompanied by latent atherosclerotic lesions in the cervical and intracranial arteries besides silent brain infarction in patients with CAD.

Adult↗
PubMed2003

Focal fractionated radiotherapy for intramedullary spinal arteriovenous malformations: 10-year experience.

OBJECT: Radiosurgical treatment of spinal arteriovenous malformations (AVMs) is becoming a practical therapeutic option as methodology improves, but no comparative study has yet been published on focal fractionated radiotherapy. The authors report their experience with conventional and hypofractionated radiotherapy for spinal AVM. METHODS: Candidates for this study were patients who experienced symptoms due to an intramedullary AVM but were ineligible for embolization or surgery. Of 21 patients with spinal AVMs, 10 cases in a 10-year period met this criterion. Angiography and contrast-enhanced computerized tomography scanning were used for treatment planning in all cases. Fractionated radiotherapy was performed using a linear accelerator, extracranial immobilization system, and frequent orthogonal linacographic verification. The starting radiation dose was 32 Gy in two, 36 Gy in three, and 40 Gy in two patients, in a regimen involving 1.8 to 2-Gy daily fractions; this was recently changed to a hypofractionation schedule of 30 Gy (in eight sessions) in one and 20 Gy (in four sessions) in two patients. RESULTS: The follow-up period ranged from 26 to 124 months (median of 49 months). There were no hemorrhages nor any adverse reactions attributable to irradiation. Of the seven patients who consented to undergo follow-up angiography, the nidus size decreased in five, but complete obliteration did not occur in any patient. CONCLUSIONS: Because no patient experienced adverse effects, the maximum tolerable radiation dose for the spinal cord associated with an AVM could not be identified, although it presumably is higher than those administered. The lack of rebleeding in patients in whom complete angiographic occlusion was absent suggests that the natural history of spinal AVMs may be less aggressive than previously reported.

Adolescent↗
PubMed2002

Calculation of rotational setup error using the real-time tracking radiation therapy (RTRT) system and its application to the treatment of spinal schwannoma.

PURPOSE: The efficacy of a prototypic fluoroscopic real-time tracking radiation therapy (RTRT) system using three gold markers (2 mm in diameter) for estimating translational error, rotational setup error, and the dose to normal structures was tested in 5 patients with spinal schwannoma and a phantom. METHODS AND MATERIALS: Translational error was calculated by comparing the actual position of the marker closest to the tumor to its planned position, and the rotational setup error was calculated using the three markers around the target. Theoretically, the actual coordinates can be adjusted to the planning coordinates by sequential rotation of gamma degrees around the z axis, beta degrees around the y axis, and alpha degrees around the x axis, in this order. We measured the accuracy of the rotational calculation using a phantom. Five patients with spinal schwannoma located at a minimum of 1-5 mm from the spinal cord were treated with RTRT. Three markers were inserted percutaneously into the paravertebral deep muscle in 3 patients and surgically into two consecutive vertebral bones in two other patients. RESULTS: In the phantom study, the discrepancies between the actual and calculated rotational error were -0.1 +/- 0.5 degrees. The random error of rotation was 5.9, 4.6, and 3.1 degrees for alpha, beta, and gamma, respectively. The systematic error was 7.1, 6.6, and 3.0 degrees for alpha, beta, and gamma, respectively. The mean rotational setup error (0.2 +/- 2.2, -1.3 +/- 2.9, and -1.3 +/- 1.7 degrees for alpha, beta, and gamma, respectively) in 2 patients for whom surgical marker implantation was used was significantly smaller than that in 3 patients for whom percutaneous insertion was used (6.0 +/- 8.2, 2.7 +/- 5.9, and -2.1 +/- 4.6 degrees for alpha, beta, and gamma). Random translational setup error was significantly reduced by the RTRT setup (p < 0.0001). Systematic setup error was significantly reduced by the RTRT setup only in patients who received surgical implantation of the marker (p < 0.0001). The maximum dose to the spinal cord was estimated to be 40.6-50.3 Gy after consideration of the rotational setup error, vs. a planned maximum dose of 22.4-51.6 Gy. CONCLUSION: The RTRT system employing three internal fiducial markers is useful to reduce translational setup error and to estimate the dose to the normal structures in consideration of the rotational setup error. Surgical implantation of the marker to the vertebral bone was shown to be sufficiently rigid for the calculation of the rotational setup error. Fractionated radiotherapy for spinal schwannoma using the RTRT system may well be an alternative or supplement to surgical treatment.

Adolescent↗
PubMed2002

Image fusion between 18FDG-PET and MRI/CT for radiotherapy planning of oropharyngeal and nasopharyngeal carcinomas.

PURPOSE: Accurate diagnosis of tumor extent is important in three-dimensional conformal radiotherapy. This study reports the use of image fusion between (18)F-fluoro-2-deoxy-D-glucose positron emission tomography (18FDG-PET) and magnetic resonance imaging/computed tomography (MRI/CT) for better targets delineation in radiotherapy planning of head-and-neck cancers. METHODS AND MATERIALS: The subjects consisted of 12 patients with oropharyngeal carcinoma and 9 patients with nasopharyngeal carcinoma (NPC) who were treated with radical radiotherapy between July 1999 and February 2001. Image fusion between 18FDG-PET and MRI/CT was performed using an automatic multimodality image registration algorithm, which used the brain as an internal reference for registration. Gross tumor volume (GTV) was determined based on clinical examination and 18FDG uptake on the fusion images. Clinical target volume (CTV) was determined following the usual pattern of lymph node spread for each disease entity along with the clinical presentation of each patient. RESULTS: Except for 3 cases with superficial tumors, all the other primary tumors were detected by 18FDG-PET. The GTV volumes for primary tumors were not changed by image fusion in 19 cases (89%), increased by 49% in one NPC, and decreased by 45% in another NPC. Normal tissue sparing was more easily performed based on clearer GTV and CTV determination on the fusion images. In particular, parotid sparing became possible in 15 patients (71%) whose upper neck areas near the parotid glands were tumor-free by 18FDG-PET. Within a mean follow-up period of 18 months, no recurrence occurred in the areas defined as CTV, which was treated prophylactically, except for 1 patient who experienced nodal recurrence in the CTV and simultaneous primary site recurrence. CONCLUSION: This preliminary study showed that image fusion between 18FDG-PET and MRI/CT was useful in GTV and CTV determination in conformal RT, thus sparing normal tissues.

Adult↗
PubMed2002

Induction chemotherapy followed by low-dose involved-field radiotherapy for intracranial germ cell tumors.

PURPOSE: To investigate the efficacy of chemotherapy followed by low-dose involved-field radiotherapy for the treatment of intracranial germ cell tumors (GCTs). PATIENTS AND METHODS: Thirty-three patients with GCTs, including 16 pure germinomas, 11 human chorionic gonadotropin-beta (HCG-beta)-secreting germinomas, three mixed GCTs composed of immature teratomas plus germinomas (IMT/G), and three highly malignant mixed GCTs, were treated. Etoposide and cisplatin (EP) were used for the treatment of solitary pure germinomas, and ifosfamide, cisplatin, and etoposide (ICE) were used for the treatment of other GCTs. The dose schedule was 24 Gy for germinomas and 40 to 54 Gy for other GCTs. An involved-field set-up was used except for highly malignant GCTs, in which craniospinal irradiation was used. The median follow-up was 58 months (range, 18 to 102 months). RESULTS: Disease-related, overall, and relapse-free survival rates at 5 years were 100%, 93%, and 69% for all patients, 100%, 100%, and 86% for patients with pure germinomas, and 100%, 75%, and 44% for patients with HCG-beta-secreting germinomas, respectively. All six patients with nongerminomatous GCTs were alive at the last follow-up. All eight relapses (one pure germinoma, five HCG-beta-secreting germinomas, and two IMT/G), except one in a course of salvage treatment, were salvaged and free of disease at the last follow-up. No decline was observed in the full-scale, verbal, or performance intelligence quotient at 12 to 51 months after the treatment in 11 patients. CONCLUSION: Our results support an excellent prognosis after EP and ICE regimens followed by radiotherapy. Dose and volume can be reduced to 24 Gy in 12 fractions and involve a field set-up after EP chemotherapy for the treatment of pure germinomas.

Adolescent↗
PubMed2002

Registration accuracy and possible migration of internal fiducial gold marker implanted in prostate and liver treated with real-time tumor-tracking radiation therapy (RTRT).

BACKGROUND AND PURPOSE: We have developed a linear accelerator synchronized with a fluoroscopic real-time tumor-tracking system to reduce errors due to setup and organ motion. In the real-time tumor-tracking radiation therapy (RTRT) system, the accuracy of tumor tracking depends on the registration of the marker's coordinates. The registration accuracy and possible migration of the internal fiducial gold marker implanted into prostate and liver was investigated. MATERIALS AND METHODS: Internal fiducial gold markers were implanted in 14 patients with prostate cancer and four patients with liver tumors. Computed tomography (CT) was carried out as a part of treatment planning in the 18 patients. A total of 72 follow-up CT scans were taken. We calculated the relative relationship between the coordinates of the center of mass (CM) of the organs and those of the marker. The discrepancy in the CM coordinates during a follow-up CT compared to those recorded during the planning CT was used to study possible marker migration. RESULTS: The standard deviation (SD) of interobserver variations in the CM coordinates was within 2.0 and 0.4 mm for the organ and the marker, respectively, in seven observers. Assuming that organs do not shrink, grow, or rotate, the maximum SD of migration error in each direction was estimated to be less than 2.5 and 2.0 mm for liver and prostate, respectively. There was no correlation between the marker position and the time after implantation. CONCLUSION: The degree of possible migration of the internal fiducial marker was within the limits of accuracy of the CT measurement. Most of the marker movement can be attributed to the measurement uncertainty, which also influences registration in actual treatment planning. Thus, even with the gold marker and RTRT system, a planning target volume margin should be used to account for registration uncertainty.

Carcinoma, Hepatocellular↗
PubMed2002

Three-dimensional conformal radiotherapy for astrocytic tumors involving the eloquent area in children and young adults.

PURPOSE: Although a gross total removal of astrocytic tumors offers a favorable prognosis, it is often difficult to achieve in the eloquent area of the brain. This study was conducted to investigate the possible gain of three-dimensional conformal radiotherapy (3DCRT) for astrocytic tumors located in the eloquent area in children and young adults. MATERIALS AND METHODS: Twenty patients with astrocytic tumors received the radiotherapy. The median age was 17 years, ranging from 4 to 30 years. Fourteen low-grade tumors (seven pilocytic and seven diffuse), and six high-grade tumors (five anaplastic, one malignant pilocytic) were included. Tumors were located at the thalamus/hypothalamus in 12 cases, optic tract in one case, and the deep cerebral/cerebellar hemisphere in seven cases. A specific fixation device was used for 3DCRT. Forty-six Gy for low-grade tumors and 54 Gy for high-grade astrocytomas with 1.8-2.0 Gy per fraction were in principle employed as the standard regimen. Nominal radiotherapy fields ranged from 2.0 x 2.0 to 15.0 x 11.0 cm2. The median follow-up period was 42 months, ranging from 3 to 108 months. RESULTS: The actuarial survival rate at 5 years was 68% +/- 13% for all patients. The actuarial survival rate for low-grade glioma was 79% +/- 14% at 5 years and 50% +/- 20% at 3 years for high-grade glioma. The actual progression-free survival rate was 83% +/- 11% at 5 years for low-grade glioma and 50% +/- 20% for high-grade glioma. A complete response was obtained in three (21%) of 14 patients with low-grade astrocytic tumors. Two patients with low-grade tumors and four of six with high-grade tumors died due to tumor progression with infield relapse but not marginal relapse. Twelve survivors with low-grade tumors showed no signs of relapse and no neurological, hormonal, or cognitive deterioration after radiotherapy and were able to attend their school or continue with a full-time job. CONCLUSIONS: 3DCRT is safe and effective for low-grade astrocytic tumors located in the eloquent area in children and young adults.

Adolescent↗