Biomedical subjects

Naoyuki Shigematsu

Publications and source records attributed to Naoyuki Shigematsu.

At least 19 recordsLinked to original sources

PubMed2006

Repair of potentially lethal damage in normal cells and ataxia telangiectasia cells; consideration of non-homologous end-joining.

When cell lines are held in a quiescent state after irradiation, survival rates are greater than those from cells that are stimulated to grow immediately after irradiation. These differences in survival rates correspond to rates of potentially lethal damage repair. The effects of confluent holding recovery after gamma-irradiation were investigated using normal human fibroblasts (AG1522) and ataxia telangiectasia fibroblasts (GM02052). Calyculin-A-induced premature chromosome condensation and fluorescent in situ hybridization were applied to study G2/M chromosomal aberrations. Survival results indicated normal capacity for PLDR in AG1522 cells but that PLDR was extremely compromised in GM02052 cells. The chromosomal aberration frequency decreased when AG1522 cells were allowed to repair for 24-h, whereas 24-hour incubation had little effect on the aberration frequency in GM02052 cells. Since the main mechanism for dsbs repair during G0/G1 phases of the cells cycle involve the non-homologous end-joining (NHEJ) process, our study indicates that for AG1522 cells the NHEJ repair process is more likely to induce accurate chromosome repair under quiescent G0 conditions than proliferating G1 phase, while in GM02052 cells the fidelity of NHEJ is similarly defective at either cell cycle phase. Reduced fidelity of NHEJ may be responsible for PLDR defect and its hyper-radiosensitivity in A-T cells.

Ataxia Telangiectasia↗

PubMed2006

Unique treatment policy for well-differentiated thyroid cancer in Japan: results of a questionnaire distributed to members of the Japanese Society of Thyroid Surgery and the International Association of Endocrine Surgeons.

Although surgery has been the mainstay of treatment for patients with well-differentiated thyroid cancer, the extents of thyroid resection and lymph node dissection adopted in Japan differ from those in other countries. Furthermore, regarding the indications for postoperative radiation therapy and hormonal therapy, and treatment modalities for cancer recurrence, there are marked discrepancies between Japan and other countries. A questionnaire survey was thus conducted among domestic and overseas thyroid surgeons to ascertain the actual treatment policy for well-differentiated thyroid cancer in Japan and various foreign countries. For small papillary carcinomas of 2.0 cm or less (T1), thyroid resection was more extensive in foreign countries than in Japan, although the extent of lymph node dissection was limited in the former. For large papillary carcinomas exceeding 3.0 cm (T2), on the other hand, total thyroidectomy was the treatment of first choice for all overseas respondents, but of only 20% in Japan, despite lymph node dissection being more extensive in Japan than in other countries. Overseas surgeons were much more likely to favor postoperative TSH suppression therapy and high-dose (131)I therapy. For recurrence following surgery for papillary thyroid cancer, both domestic and overseas respondents indicated surgical resection to be the most common treatment option, and favored high-dose (131)I therapy as well. In Japan, however, high-dose (131)I therapy is available only in a few institutions. Such limited indications for high-dose (131)I therapy in Japan may reflect a discrepancy in the frequency of total thyroidectomy, a prerequisite for postoperative high-dose (131)I therapy, between Japan and other countries. This is the first questionnaire study conducted in both Japan and other countries in relation to treatment modalities for thyroid cancer. The results reveal that there is a clear disparity in treatment policies between Japan and foreign countries.

Americas↗

PubMed2006

Dose-volume factors predicting radiation pneumonitis in patients receiving salvage radiotherapy for postlobectomy locoregional recurrent non-small-cell lung cancer.

BACKGROUND: The correlation between treatment-related factors and lung toxicity has not been sufficiently evaluated in salvage radiotherapy. METHODS: Twenty-one patients with recurrent non-small-cell lung cancer (NSCLC) after lobectomy received salvage radiotherapy to a total dose of 46-60 Gy. The effects of radiotherapy parameters on the development of radiation pneumonitis (RP) were examined using dose-volume histograms. RESULTS: Grade 1 RP was observed in 4, grade 2 in 2, and grade 3 in 1 patient. Patients who developed RP had a significantly higher value in V dose (V13, V20) parameters and mean lung dose (MLD) than those who did not develop RP. Concerning G2 or higher RP, 3 patients who developed > or = G2 RP had a significantly higher value in V20, V13, and MLD than the remaining patients with P values of 0.01, 0.015, and 0.016, respectively. The mean V20, V13, and MLD in these 3 patients were 27%, 29.3%, and 14.8 Gy, respectively, whereas the mean V20, V13, and MLD in the remaining 18 patients were 15.8%, 18.3%, and 8.8 Gy, respectively. Three of 6 patients with a V20 > or = 20% developed > or = G2 RP whereas this did not occur in the remaining patients (P = 0.015). Similarly, 3 of 6 patients with a V13 > or = 23% developed > or = G2 RP whereas this did not occur in the remaining patients (P = 0.015). CONCLUSIONS: These data suggest that a somewhat lower V dose value or MLD, as compared with the setting of definitive radiotherapy, could be a surrogate for RP in patients undergoing salvage radiotherapy for recurrent NSCLC.

Aged↗

PubMed2006

Tamoxifen for recurrent desmoid tumor of the chest wall.

We report a case of a young woman with recurrent desmoid tumor. Computed tomography (CT) scans of the chest showed a large mass in the left chest wall. The tumor was unresectable because of the involvement of adjacent structures. Tamoxifen therapy led to marked tumor regression within 3 months. She had preserved her fertility, and thereafter she conceived a baby. In young women with recurrent desmoid tumor, tamoxifen should be considered as the first choice of treatment.

Adult↗

PubMed2006

Radiation therapy after breast-conserving surgery.

The authors critically reviewed previous articles concerning the significance of breast irradiation following breast-conserving surgery in terms of the following subject items: indications for breast-conserving therapy, the significance and complications of breast irradiation, the timing of the start of breast irradiation, the significance of boost irradiation, the potential improvement of survival with systemic therapy plus breast irradiation, the significance of axillary dissection, indications and the significance of regional nodal irradiation, accelerated hypofractionated radiotherapy, omission of breast irradiation in low-risk patients, and future directions. In addition, our previously reported results of breast irradiation following breast-conserving surgery at the Keio University Hospital are outlined. Our newly developed tangential irradiation technique directed to the axilla and a recently introduced three-dimensional simulation technique for radiotherapy treatment planning are also presented.

Breast↗

PubMed2006

Rotational and translational reproducibility of newly developed Leksell frame-based relocatable fixation system.

PURPOSE: The aim of this study was to evaluate three-dimensional movement of the cranium in a relocatable frame using positions of anatomical landmarks obtained from repeated quality-assurance (QA) computed tomography (CT) studies. MATERIALS AND METHODS: We analyzed 17 series of QA-CT data representing five patients who underwent stereotactic radiotherapy for treatment of acoustic neurinoma. Helical-CT scans with 1-mm collimation were obtained at the time of treatment planning and during the course of treatment. The right and left short processes of the incus and the top of the crista galli were used as the three anatomical reference points. RESULTS: Fluctuations in distance among the reference points were all <1 mm. The translational displacements for these points were <2 mm, with standard deviations (SD) of <2 mm. A plane that included all three reference points was defined as the reference plane. To investigate the direction of cranial rotation for each QA-CT scan, unit normal vectors of the reference plane were obtained. Three-dimensional analyses indicated that cranial rotation was greatest along the X-axis, followed by the Y-axis, with the least rotation along the Z-axis. CONCLUSION: The result suggested that movement of the craniocaudal axis in the sagittal plane was a major factor behind displacement of the cranium.

Adult↗

PubMed2006

Value of CT thallium-201 SPECT fusion imaging over SPECT alone for detection and localization of nasopharyngeal and maxillary cancers.

OBJECTIVE: The purpose of this study was to investigate the incremental clinical utility of CT and high-resolution SPECT fusion imaging. MATERIALS AND METHODS: Eighteen patients with nasopharyngeal cancer or cancers around the maxilla were scanned with high-resolution SPECT at the time of initial diagnosis (18 studies) and during follow-up after chemoradiotherapy (23 studies). SPECT results were compared with histologic findings or the findings of other imaging techniques. In addition, automatic image registration without fiducial markers was performed from CT and SPECT data, and the effect of fusion imaging on the localization of abnormalities was evaluated. RESULTS: All of the original 18 untreated lesions showed high uptake. Recurrent tumors had a tendency to show high uptake (seven of nine patients), whereas little or no uptake generally represented no recurrence (12 of 14 patients) (chi-square test with Yates correction: chi2 = 6.80, p < 0.01). In two patients, physiologic uptake in the unilateral prevertebral muscle was revealed on image fusion. In four of the nine recurrent nasopharyngeal cancers (44%), SPECT alone could not determine abnormalities in uptake sites, whereas CT/SPECT fusion imaging clearly localized the sites and was helpful for treatment strategy. CONCLUSION: High-resolution thallium-201 (201Tl) SPECT has a very high detection rate in patients with nasopharyngeal cancer and cancers around the maxilla. However, the anatomic identification or localization of the uptake sites is sometimes difficult without CT/SPECT fusion imaging. This technique without external markers is practically feasible to generate clinically valid fusion images.

Adult↗

PubMed2006

[A recent trial of chemo-radiation with S-1 against gastric cancer].

A recent development of novel anticancer agents like S-1, CPT-11 or taxanes has improved a therapeutic outcome for advanced gastric cancer, while conventional anticancer agents showed less anticancer effect against gastric cancer. The present main drug in Japan is S-1, which is easily used for outpatient with a high efficacy rate and low toxicity, also shows better effect in combination with other anticancer drugs than S-1 alone. In the present article, we demonstrated significant meaning of additional radiation therapy with anticancer drugs like S-1. With novel anticancer drugs like S-1, we will expose a clinical advantage and appropriateness for chemo-radiation therapy against gastric cancer discussed in the present references according to chemo-radiation therapy. Although chemo-radiation therapy has been recognized as one of the standard therapies for gastric cancer in Western countries, radiation therapy was selected in Japan for palliation therapy of recurrent disease or a terminal cancer to improve patients' QOL. On the other hand, we demonstrated in our trial of chemo-radiation therapy with S-1/low-dose CDDP/radiation (TSLDR), which was applied to initial treatment against highly advanced Stage IV gastric cancer and revealed the usefulness of the regimen in anticancer effect and toxicity. In addition, chemo-radiation therapy including novel anticancer agents like S-1 will be discussed based on various kinds of view points, expecting a better clinical outcome of multimodal therapies against advanced gastric cancer.

Adult↗

PubMed2005

Small lung tumors: long-scan-time CT for planning of hypofractionated stereotactic radiation therapy--initial findings.

PURPOSE: To prospectively use long-scan-time computed tomography (CT) to visualize the trajectory of tumor movements or the internal target volume. MATERIALS AND METHODS: The study was approved by the institutional review board. Written informed consent was obtained from participants after the study and the role of procedures were explained fully. During the planning of stereotactic radiation therapy for 10 patients (nine men, one woman; mean age, 77 years; range, 69-89 years) with small lung tumors (mean volume, 9.0 cm3; range, 3.6-24.9 cm3), fluoroscopic imaging, long-scan-time CT, and thin-section CT were performed. The tumor and the partial-volume-averaging effects that resulted from tumor movement were delineated on each section at long-scan-time CT performed during the patient's steady breathing with scan time of 8 seconds per image. Visualized internal target volume was defined by integrating the sections. A simple model was examined for estimating internal target volume on the basis of respiratory motion and gross target volume delineated on thin-section CT images. Visualized internal target volume and estimated internal target volume were compared quantitatively and graphically. The Mann-Whitney test was used to analyze the relation between gross target volume delineated on thin-section CT images and the ratio of visualized internal target volume to the defined gross target volume. RESULTS: The correlation coefficient between visualized internal target volume and estimated internal target volume was r = 0.98 (P < .001). The mean relative error +/- standard deviation was 1.9% +/- 19.0 (range, -11.0% to 56.4%). Excluding one case with an irregularly shaped tumor (56.4%), the mean relative error was -4.1% +/- 4.1. In patients with small tumors (defined gross target volume, < or = 10 cm3), the ratio of the visualized internal target volume to the defined gross tumor volume was significantly larger than that in patients with larger tumors (1.2-2.0 vs 1.0-1.2; P < .05). In some cases in which marginal spiculation depicted on thin-section CT images was blurred on long-scan-time CT images, the blurred area was erroneously excluded from the target volume. CONCLUSION: In most cases, values for visualized internal target volume and estimated internal target volume were similar and long-scan-time CT depicted virtually the entire tumor trajectory.

Aged↗

PubMed2005

Differences in pulmonary function before vs. 1 year after hypofractionated stereotactic radiotherapy for small peripheral lung tumors.

PURPOSE: To evaluate long-term pulmonary toxicity of stereotactic radiotherapy (SRT) by pulmonary function tests (PFTs) performed before and after SRT for small peripheral lung tumors. METHODS AND MATERIALS: A total of 17 lesions in 15 patients with small peripheral lung tumors, who underwent SRT between February 2000 and April 2003, were included in this study. Twelve patients had primary lung cancer, and 3 patients had metastatic lung cancer. Primary lung cancer was T1-2N0M0 in all cases. Smoking history was assessed by the Brinkman index (number of cigarettes smoked per day multiplied by number of years of smoking). Prescribed radiation doses at the 80% isodose line were 40-60 Gy in 5-8 fractions. PFTs were performed immediately before SRT and 1 year after SRT. Test parameters included total lung capacity (TLC), vital capacity (VC), forced expiratory volume in 1 s (FEV1.0), and diffusing capacity of lung for carbon monoxide (DLCO). PFT changes were evaluated in relation to patient- and treatment-related factors, including age, the Brinkman index, internal target volume, the percentages of lung volume irradiated with >15, 20, 25, and 30 Gy (V15, V20, V25, and V30, respectively), and mean lung dose. RESULTS: There were no significant changes in TLC, VC, or FEV1.0 before vs. after SRT. The mean percent change from baseline in DLCO was significantly increased by 128.2%. Univariate and multivariate analyses revealed a correlation between DLCO and the Brinkman index. CONCLUSIONS: One year after SRT as compared with before SRT, there were no declines in TLC, VC, and FEV1.0. DLCO improved in patients who had been heavy smokers before SRT, suggesting a correlation between DLCO and smoking cessation. SRT seems to be tolerable in view of long-term lung function.

Aged↗

PubMed2005

Postoperative pelvic radiotherapy for cervical cancer patients with positive parametrial invasion.

OBJECTIVE: To evaluate patterns of failure in cervical cancer patients with histopathologic parametrial invasion treated with postoperative pelvic radiation therapy. METHODS: Records of 117 stages IB-IIB cervical cancer patients with parametrial invasion treated with postoperative radiation therapy from 1985 to 2002 were retrospectively reviewed. Patients were divided into two groups based on status of pelvic lymph nodes. Patterns of recurrence and prognosis by status of pelvic lymph nodes were statistically analyzed. RESULTS: Status of pelvic lymph nodes had significant impact on both recurrence and survival. Extrapelvic recurrence was observed in 23 of 66 node-positive patients compared with 6 of 51 node-negative patients (P = 0.005). Of 66 patients with a positive pelvic lymph node, 18 developed visceral metastases, whereas only three visceral metastases were noted in the 51 node-negative patients (P = 0.003). Five-year overall survival in node-positive and -negative patients was 52% and 89%, respectively (P = 0.0005). Corresponding rates for recurrence-free survival were 44% and 83%, respectively (P = 0.0002). The correlation between nodal metastasis and prognosis was enhanced when node-positive patients were stratified into two groups based on number of positive nodes (n = 1 and n > or = 2). Five-year recurrence-free survival rates for patients with negative, one positive, and two or more positive nodes were 83%, 61%, and 31%, respectively (P = 0.0001). CONCLUSIONS: Extrapelvic recurrence was uncommon in node-negative patients with parametrial invasion. These findings do not support use of systemic therapy for cervical cancer patients with parametrial invasion if pelvic lymph node metastasis is negative.

Adult↗

PubMed2005

Hyperfractionated radiation therapy for locoregionally advanced nasopharyngeal cancer.

OBJECTIVE: The purpose of this study is to clarify the efficacy and toxicity of hyperfractionated radiation therapy (RT) for patients with nasopharyngeal cancer (NPC). METHODS: Twenty-two patients with NPC treated at our hospital between April 1994 and December 2002 were the subjects of this study. They received hyperfractionated RT with a fraction size of 1.2 Gy, with a median tumor dose of 72 Gy (range 64.8-80.4). During this study period, our institutional strategy for locoregionally advanced NPC included neoadjuvant or concurrent chemotherapy combined with hyperfractionated RT, and 17 patients received some forms of cisplatin-containing chemotherapy. RESULTS: With a median follow-up of 59 months, the estimated 5-year disease-free survival rate and overall survival rate were 72.7 and 85.2%, respectively. Acute hematological toxicities were acceptable and manageable. However, >50% of patients required nutritional support, and experienced severe pharyngitis, skin reaction and body weight loss. With regard to late sequelae, one patient developed grade 3 osteomyelitis, and one patient each developed grade 4 passage disturbance and laryngeal edema. No patients experienced any grades of optic nerve injury or temporal lobe necrosis. CONCLUSIONS: Hyperfractionated RT using 1.2 Gy per fraction, for a total dose of 72 Gy, produces a comparable treatment outcome. Although deleterious neurological sequelae were not observed in this study, caution should be exercised regarding other late sequelae, such as osteomyelitis and passage disturbance.

Adult↗

PubMed2005

Nationwide survey on the treatment policy for well-differentiated thyroid cancer -- results of a questionnaire distributed at the 37th meeting of the Japanese Society of Thyroid Surgery.

The treatment policy for patients with well-differentiated thyroid cancer varies among institutions. Although surgery has been the mainstay of treatment for this cancer, there is no consensus concerning the optimal extent of thyroid resection or the extent of lymph node dissection. Furthermore, controversy remains with regard to the indications for radiation therapy and hormonal therapy in surgical or non-surgical cases and the treatment modalities for cancer recurrence. To determine the actual status of treatment policies for thyroid cancer in Japan, a questionnaire was distributed to all physicians who participated in the 37th meeting of the Japanese Society of Thyroid Surgery, to inquire into treatment options for well-differentiated thyroid cancer in relation to clinical stages in actual situations. The replies to this questionnaire were analyzed in this study.

Carcinoma, Papillary↗

PubMed2005

Relation between chromosomal aberrations and radiation dose during the process of TBI.

PURPOSE: The purposes of this study were (1) to consider the dose-response relationship in-vivo at high dose range by using the Colcemid method, which begins with predicting the risk of future late complication caused by a fixed dose of chromosomal aberration of peripheral lymphocytes after radiation emission and (2) to compare in-vivo and in-vitro dose-responses for chromosomal aberrations in lymphocytes of cancer patients undergoing total body irradiation (TBI). METHODS: Eight patients diagnosed with hematological malignancies entered this study. TBI planning with a 6 MV linear accelerator consisted of 4 Gy/2 fractions/day, and the total treatment dose was 12 Gy. RESULTS: At the observable dose range of up to 10 Gy, the unstable chromosomal aberrations of both dicentrics and fragments increased with the increment of irradiated dose, regardless of in-vivo or in-vitro irradiated samples. However, the average number of dicentrics and fragments obtained from in-vitro samples was found to be higher than that for in-vivo samples. CONCLUSION: This result strongly suggests that in-vivo dose-response curves are necessary to estimate the absorbed dose in-vivo. In-vivo dose-response curves obtained from cancer patients would be very important for standard curves for biodosimetry.

Chromosome Aberrations↗

PubMed2005

Is chemoradiation effective or harmful for stage VI gastric cancer patients?

We aim to clarify beneficial effect of pre-operative radiation with chemotherapy in highly advanced gastric cancer patients, evaluating histological response, toxicity and patients' quality of life (QOL). We used pre-operative radiation with S-1 and low-dose cisplatin to treat 8 patients with highly advanced gastric cancer (clinical stage IV) in a pilot study. Clinical staging after therapy showed 5 PRs (partial response), 2 NCs (no change), and 1 PD (partial disease) following evaluation of the primary tumor and suspicious metastatic lesions in the lymph nodes, esophagus, liver, and peritoneum, for a response rate of 62.5% (5/8 cases). Of 8 patients, 6 underwent surgery, and 2 of these 6 patients had a histologically complete response (grade 3 effect) and 3 patients had a partial response (grade 2 effect), suggesting that a high histological response (5/6 cases; 83.3%) is expected by the chemoradiation. The survival analysis showed that 5 out of the 8 patients died within 10 months after initiating therapy, while 3 patients are alive without recurrence at 15, 18, and 30 months after therapy, suggesting a relatively good outcome for clinical stage IV gastric cancer. All cases showed grade 2-4 bone marrow suppression toxicity and/or grade 0-2 gastro-intestinal toxicity, while 5 out of 8 patients (62.5%) showed improvement in appetite loss at the end of the therapy, indicating that the patients' quality of life (QOL) was preserved. Chemoradiation may be a powerful regimen for obtaining histological response with tolerable toxicity and improved QOL in highly advanced gastric cancer patients.

Adult↗

PubMed2004

Treatment of breast carcinoma in patients with clinically negative axillary lymph nodes using radiotherapy versus axillary dissection.

BACKGROUND: The role of axillary lymph node dissection (AxD) for patients with breast carcinoma who have clinically negative lymph nodes (cN0) and undergo breast-conserving therapy has been controversial. If patients do not undergo AxD, then it is uncertain whether specific lymph node irradiation should be given. The authors compared the results obtained from patients w ho underwent AxD with the results from patients who received axillary irradiation (AxR) using one of two radiotherapy techniques. METHODS: Patients with T1-T2cN0 breast carcinoma were treated from 1983 to 2002 with either AxD (80 patients) or AxR (1134 patients received tangential-field [2-field] irradiation, and 303 patients received 3-field irradiation). The median follow-up was 161 months for the AxD group and 66 months for the AxR group (55 months for patients who received tangential-field irradiation, and 122 months for patients who received 3-field irradiation). RESULTS: One patient in the AxD group and 35 patients in the AxR group had axillary recurrences. The 10-year cumulative axillary recurrence rates were 1.3% and 4.6% for the AxD group and the AxR group, respectively (P = 0.21). For patients with T1 tumors, the 10-year overall survival rates for the two groups were 94.7% and 92.7%, respectively (P = 0.34); and, for patients with T2 tumors, the 10-year overall survival rates were 92.5% and 89.1%, respectively (P = 0.34). In the AxR group, the 5-year axillary recurrence rates were 2.5% for patients who received tangential-field irradiation and 1.7% for patients who received 3-field irradiation (P = 0.18), and the 5-year regional recurrence rates for the two groups were 4.8% and 2.4%, respectively (P = 0.048). On multivariate analysis, positive lymphovascular invasion, outer tumor location, and larger tumor size were significant risk factors for regional failure. CONCLUSIONS: For patients with cN0 breast carcinoma, AxD and AxR yielded the same overall survival rates. Most patients can be treated safely with tangential-field irradiation alone. Patients who are at increased risk of regional failure may benefit from three-field irradiation.

Adult↗

PubMed2004

Evaluation of novel modified tangential irradiation technique for breast cancer patients using dose-volume histograms.

PURPOSE: We have previously reported that entire axillary lymph node regions could be irradiated by the modified tangential irradiation technique (MTIT). In this study, MTIT was compared with a conventional irradiation technique (CTIT) using dose-volume histograms to verify how adequately MTIT covers the breast and axillary lymph node region and the extent to which it involves the lung and heart. METHODS AND MATERIALS: Forty-four patients with early-stage breast cancer were treated by lumpectomy, axillary dissection, and postoperative radiotherapy. Twenty-two patients were treated with MTIT and 22 with CTIT. In 25 patients, the breast tumor was on the left and in 19 on the right. During axillary dissection, surgical clips were left as markers at the border of the axillary lymph node region. MTIT was planned by setting the dorsal edge of the radiation field on a lateral-view simulator film at the dorsal edge of the humeral head and the cranial edge of the radiation field at the caudal edge of the humeral head. CTIT was planned to ensure radiation of the breast tissue without considering the axillary region. In this study, all patients underwent computed tomography, and the CT data were transmitted on-line to a radiotherapy planning system, in which the dose-distribution computed tomography images and dose-volume histograms were calculated by defining the breast, axillary region (levels I, II, and III), lung, and heart region. RESULTS: Dose-volume histogram analysis demonstrated that breast tissue was radiated with an 86.5-100% volume (median 96.5%) by MTIT and an 83-100% volume (median, 95%) by CTIT at >95% of the isocenter dose. The axillary lymph node regions at Levels I, II, and III were irradiated with 84-100% (median, 94.5%), 59-100% (median, 89%), and 70-100% (median, 89.5%) volumes, respectively, by MTIT and with 2-84% (median, 38%), 0-53% (median, 15%), and 0-31% (median, 0%) volumes, respectively, by CTIT at >70% of the isocenter dose. The ipsilateral lung was irradiated with a 5-22% volume (median, 11.5%) by MTIT and 5-15% volume (median 9%) by CTIT at >90% of the isocenter dose. In all 25 left-sided breast cancer patients, the volumes irradiated with an 80% isocenter dose were <30 cm(3). CONCLUSION: The results of our study demonstrated that the breast tissue was sufficiently irradiated with both CTIT and MTIT planning, the axillary lymph node areas irradiated by MTIT were much wider than those irradiated by CTIT at all levels, and the lung and heart volumes irradiated by MTIT were small.

Adult↗

PubMed2004

Measurement of beam-axis displacement from the isocenter during three-dimensional conformal radiosurgery with a micro-multileaf collimator.

We describe the displacement of the beam-axis from the planning isocenter in clinical situations during three-dimensional conformal radiosurgery using an Acculeaf bi-directional micro-multileaf collimator. The displacements were recorded for 64 ports using a video imaging system and a stereotactic arc. The mean displacement was 0.41+/-0.25 mm.

Brain Neoplasms↗