Haruyuki Fukuda

Non-small-cell lung cancer: reirradiation for loco-regional relapse previously treated with radiation therapy.

BackgroundWe evaluated the efficacy and toxicity of reirradiation for patients with loco-regional relapse of non-small-cell lung cancer after radiation therapy.MethodsBetween 1992 and 2002, 19 patients with loco-regional relapse underwent reirradiation. The median interval between the initial irradiation and reirradiation was 16 months, with a range of 5 to 60 months. The prescribed dose of reirradiation was 50 Gy in 25 fractions over 5 weeks for 18 patients and 60 Gy in 30 fractions over 6 weeks for 1 patient.ResultsFive patients could not receive the prescribed dose of reirradiation. The response rate was 43% among the 14 patients who received the prescribed dose of reirradiation. The overall 1-year and 2-year Kaplan-Meier survival rates were 26% and 11%, respectively, and the median survival time was 7.1 months. The median survival times associated with intervals between the initial irradiation and reirradiation of less than 12 months, 12–18 months, and more than 18 months were 2.1, 7.1, and 11.5 months, respectively. There were significant differences in survival between patients with an interval of less than 12 months and those with an interval of 12–18 months, and between those with an interval of less than 12 months and those with an interval of more than 18 months (generalized Wilcoxon method; P < 0.05 for both). Grade 3 radiation pneumonitis and grade 2 radiation esophagitis occurred in 1 and 3 patients, respectively.ConclusionReirradiation is considered to contribute to salvage in selected patients with relapsed non-small-cell lung cancer. Patients with a long interval after the initial irradiation are good candidates for reirradiation. On the other hand, patients with Eastern Cooperative Oncology Group (ECOG) performance status 3 were not goodcandidates.

Use of FDG-microPET for detection of small nodules in a rabbit model of pulmonary metastatic cancer

ObjectiveThe performance of microPET using18F-FDG was evaluated in a rabbit model of hematogenous pulmonary metastatic cancer.MethodsA total of 15 Japanese white rabbits and VX-2 carcinoma were used in this study. In the microPET study, tumor-bearing rabbits were administered intravenously 74 MBq of18F-FDG, and 30 min later, the emission data were acquired for 60 min. The transmission scans were performed with a68Ge/68Ga external point source. To augment the anatomical information, we performed multi-detector row computed tomography (MDCT) in the combination with MDCT and microPET on 10 rabbits. The other 5 rabbits were followed once a week for 5 weeks only by microPET. Tumor/muscle (T/M) ratios were used for quantitative evaluation in this study.ResultsMultiple pulmonary nodules were detected by MDCT and microPET starting 14 days after the tumor injection. The high-uptake lesions in the lung detected by microPET corresponded well to the tumors detected by MDCT. The smallest nodule detected by microPET was ca. 1.5 mm in diameter. Overall, 87 nodules were detected by MDCT and the ratios of lesions detected by microPET to those by MDCT were 35.3%, 77.5%, and 90% for tumors equal to or smaller than 2 mm, 2-4 mm, and 4-6 mm in diameter, respectively. The respective T/M ratios were 2.41 ±0.41, 2.93 ± 0.55, and 3.34 ±0.71. The T/M ratio increased with tumor size, but it was similar in each tumor size category. In the 35-day follow-up protocol, it was possible to follow sequentially the same tumor by the microPET.ConclusionsBy FDG-microPET, it is possible to evaluate tumors larger than 2 mm in diameter and to follow the growth of individual tumors. Our results also suggest that the rabbit model of VX-2 pulmonary metastasis is a stable experimental model for evaluation using FDG. Monitoring of the therapeutic effects of anticancer drugs and radiation therapy could be tried by using this model and microPET.

Non-small cell lung cancer: radiation therapy for locoregional recurrence after complete resection

BackgroundWe investigated patterns of failure after radical radiation therapy in relation to the radiation field in patients with postsurgical locoregional recurrence of non-small cell lung cancer.MethodsBetween 1992 and 2002, 31 patients with locoregional recurrence were treated with radiation therapy. At the time of radiation therapy, the sites of recurrence were the bronchial stump, the regional lymph nodes, the chest wall, and both the regional lymph nodes and the chest wall in 7, 20, 3, and 1 patient, respectively. The prescribed dose was 60 Gy in 30 fractions over 6 weeks in all patients.ResultsThe response rate was 87%. The overall 1-year, 2-year, and 4-year Kaplan-Meier survival rates were 61%, 30%, and 15%, respectively, and the median survival time was 14 months. Locoregional relapse with or without distant metastasis occurred in 15 patients (in-field, 7; marginal, 7; out-field, 1), and distant metastasis alone occurred in 7 patients. The sites of marginal relapse were the upper margin in two patients, the ipsilateral margin in one patient, the contralateral margin in one patient, and the lower margin in three patients, respectively (in one patient, the data for marginal relapse overlapped). In all patients with relapse on the lower margin, the mediastinal lymph nodes were dissected at the initial surgery.ConclusionPostoperative recurrent non-small cell lung cancer showed distinctive features: the response rate was high, and the incidence of marginal relapse was also high, as in small cell lung cancer. The incidence of lower marginal relapse was high, in contrast to that in surgery-naive patients.

A Phase I Study of Chemoradiotherapy With Use of Involved-Field Conformal Radiotherapy and Accelerated Hyperfractionation for Stage III Non-Small Cell Lung Cancer: WJTOG 3305

PURPOSE A Phase I study to determine a recommended dose of thoracic radiotherapy using accelerated hyperfractionation for unresectable non-small-cell lung cancer was conducted. METHODS AND MATERIALS Patients with unresectable Stage III non-small-cell lung cancer were treated intravenously with carboplatin (area under the concentration curve 2) and paclitaxel (40 mg/m(2)) on Days 1, 8, 15, and 22 with concurrent twice-daily thoracic radiotherapy (1.5 Gy per fraction) beginning on Day 1 followed by two cycles of consolidation chemotherapy using carboplatin (area under the concentration curve 5) and paclitaxel (200 mg/m(2)). Total doses were 54 Gy in 36 fractions, 60 Gy in 40 fractions, 66 Gy in 44 fractions, and 72 Gy in 48 fractions at Levels 1 to 4. The dose-limiting toxicity, defined as Grade ≥4 esophagitis and neutropenic fever and Grade ≥3 other nonhematologic toxicities, was monitored for 90 days. RESULTS Of 26 patients enrolled, 22 patients were assessable for response and toxicity. When 4 patients entered Level 4, enrollment was closed to avoid severe late toxicities. Dose-limiting toxicities occurred in 3 patients. They were Grade 3 neuropathy at Level 1 and Level 3 and Grade 3 infection at Level 1. However, the maximum tolerated dose was not reached. The median survival time was 28.6 months for all patients. CONCLUSIONS The maximum tolerated dose was not reached, although the dose of radiation was escalated to 72 Gy in 48 fractions. However, a dose of 66 Gy in 44 fractions was adopted for this study because late toxicity data were insufficient.

Effectiveness of the single-shot dual-energy subtraction technique for portal images

The aim of the present study was to evaluate the clinical efficacy of the single‐shot dual‐energy subtraction technique for obtaining portal images. We prepared two storage phosphor plates for this study. A 1 mm thick tungsten sheet was placed between the two storage phosphor plates. A single use of the double‐exposure technique provides two portal images simultaneously (i.e., a standard image and a low‐contrast image), using the same patient position and with no additional radiation delivered to the patient. A bone‐enhanced image is created by image subtraction between these two images. For evaluation of clinical efficacy, three treatment sites — the brain, lung, and pelvis — were imaged. Ten sets of images were obtained for each site, and five landmarks were selected for each treatment site. The visibility of each landmark and the ease of overall verification for the selected treatment sites were assessed separately for the standard and bone‐enhanced images. Four observers consisting of one radiation oncologist and three radiation therapists participated in the present study. For most of the landmarks studied, the bone‐enhanced images were significantly superior to the standard images. Regarding the ease of overall verification, the bone‐enhanced images were significantly superior to the standard images at all sites. The p‐values of mean rating for the brain, lung, and pelvis were 0.002, 0.012, and 0.003, respectively. The bone‐enhanced images obtained using our technique increased the image quality in terms of bone visibility, and are considered useful for routine clinical practice. PACS number: 87.56.Da

Accelerated hyperfractionated irradiation with concomitant boost for stage II laryngeal cancer and locally advanced head and neck cancer.

Objective This study was conducted to evaluate the efficacy and feasibility of our accelerated hyperfractionation with concomitant boost for stage II laryngeal cancer and stages III–IVb locally advanced head and neck cancer. Patients and methods From January 2000 to October 2001, eight patients with AJCC 1998 stage II laryngeal cancer and 11 patients with AJCC 1998 stages III–IVb locally advanced head and neck cancer underwent accelerated hyperfractionated radiation therapy. For the stage II laryngeal cancer, radiation was delivered at a 2.0 Gy fraction a day, 5 fractions per week for the first 3 weeks, then 2 fractions (1.8 and 1.2 Gy) a day, 5 times a week for 2.5 weeks, with total dose of 69 Gy. For stages III–IVb head and neck cancer, radiation was given at a 1.8 Gy fraction a day, 5 fractions per week for 6 weeks and a boost was added up to 70.5 Gy with 1.5 Gy as a second daily fraction during the last 2.2 weeks. Among the patients, 16 (84%) received concomitant chemotherapy, mainly with low-dose carboplatin. Acute toxicity based on RTOG criteria and tumor response at 1 month post-treatment were estimated as initial effects. Results The overall response rate was 100% in patients with stage II laryngeal cancer and 91% in patients with stages III and IVb head and neck cancer. The incidence of grade 3 or worse acute effects was 47%. Eighteen patients (95%) completed radiation therapy without interruption related to acute side effects, while one had prolongation of the treatment for more than 1 week because of neutropenia. Conclusions Our results demonstrated that accelerated hyperfractionation, mostly combined with concomitant chemotherapy, had a good overall response rate with acceptable toxicity in stage II laryngeal cancers and stages III–IVb head and neck tumors.

Dosimetric comparison of irregular surface compensator and field-in-field for whole breast radiotherapy

Purpose: The purpose of the present study was to evaluate the dosimetric benefits of the irregular surface compensator (ISC) technique for whole breast radiotherapy compared with the field-in-field (FIF) technique. Materials and Methods: Radiotherapy was planned using both techniques in 50 breast cancer patients (25 left sided and 25 right sided). The Eclipse treatment planning system (Varian Medical Systems) was used for dose calculations. For the FIF technique, subfields were added to the main fields to reduce hot and cold regions; for the ISC technique, the fluence editor application was used to extend the optimal fluence. Planning target volume dose, dose homogeneity index (DHI), maximum dose, ipsilateral lung, and heart doses for the left breast irradiation and monitor unit (MU) counts required for treatment were compared between the two techniques. Results: Compared with the FIF technique, the ISC technique significantly decreased DHI values and volumes receiving >105% of the prescription dose, and increased volumes receiving >95% of the dose and MU count (P < 0.01 for all comparisons). For the heart and ipsilateral lung, the FIF technique significantly reduced volumes receiving >5 Gy compared with the ISC technique (P < 0.01); however, volumes receiving >10, 20, and 30 Gy and the values of a mean dose did not differ significantly between the techniques (P > 0.05). Conclusions: The ISC technique is preferred over the FIF technique.

Investigation of optimal display size for viewing T1-weighted MR images of the brain using a digital contrast-detail phantom

We clarified the relationship between the display size of MRI images and observer performance using a digital contrast‐detail (d‐CD) phantom. The d‐CD phantom was developed using Microsoft Visual Basic 2010 Express. It had a 512×512 matrix in size and a total of 100 holes, whose diameter increased stepwise from 4 to 40 pixels with a 4‐pixel interval in the vertical direction; the contrast varied stepwise in the horizontal direction. The digital driving level (DDL) of the background, the width of the DDL, and the contrast were adjustable. These parameters were determined on the basis of the actual T1‐weighted magnetic resonance (MR) images of the brain. In this study, the DDL, width, and contrast were set to 85, 20, and 1, respectively. The observer performance study was performed for three different display sizes (30 cm×30 cm as the enlarged size, 16 cm×16 cm as the original size, and 10 cm×10 cm as the reduced size) using a 2‐megapixel color liquid crystal display monitor, and it was analyzed using Friedman and Wilcoxon statistical tests. The observer performances for the original display (p<0.01) and the reduced display sizes (p<0.01) were superior to that observed for the enlarged size, whereas there was no significant difference between the original display and reduced display sizes (p=0.31). Evaluation with the digital phantom simulating MR imaging also revealed that the original and reduced display sizes were superior to the enlarged display size in observer performance. The d‐CD phantom enables a short‐term evaluation of observer performance and is useful in analyzing relationship between display size and observer performance. PACS number: 87.57.‐sWe clarified the relationship between the display size of MRI images and observer performance using a digital contrast-detail (d-CD) phantom. The d-CD phantom was developed using Microsoft Visual Basic 2010 Express. It had a 512×512 matrix in size and a total of 100 holes, whose diameter increased stepwise from 4 to 40 pixels with a 4-pixel interval in the vertical direction; the contrast varied stepwise in the horizontal direction. The digital driving level (DDL) of the background, the width of the DDL, and the contrast were adjustable. These parameters were determined on the basis of the actual T1-weighted magnetic resonance (MR) images of the brain. In this study, the DDL, width, and contrast were set to 85, 20, and 1, respectively. The observer performance study was performed for three different display sizes (30 cm×30 cm as the enlarged size, 16 cm×16 cm as the original size, and 10 cm×10 cm as the reduced size) using a 2-megapixel color liquid crystal display monitor, and it was analyzed using Friedman and Wilcoxon statistical tests. The observer performances for the original display (p<0.01) and the reduced display sizes (p<0.01) were superior to that observed for the enlarged size, whereas there was no significant difference between the original display and reduced display sizes (p=0.31). Evaluation with the digital phantom simulating MR imaging also revealed that the original and reduced display sizes were superior to the enlarged display size in observer performance. The d-CD phantom enables a short-term evaluation of observer performance and is useful in analyzing relationship between display size and observer performance. PACS number: 87.57.-s.

Patient setup verification procedure for a portal image in a computed radiography system with a high-resolution liquid-crystal display monitor

In our conventional visual inspection for setup verification, we have routinely used a console monitor of a CR system and a monitor of a treatment-planning system (i.e., the separate-monitor method) in order to avoid the need for CR portal-film generation. However, the separate-monitor method provided insufficient precision in detecting setup errors. We devised a setup verification procedure that uses a high-resolution liquid-crystal display monitor (i.e., the single-monitor method). Our objective in the present study was to evaluate the precision of the single-monitor method. These two methods were compared in terms of the precision of visual inspection. The single-monitor method was significantly superior to the separate-monitor method in sensitivity and in the magnitude of the discrepancy that could not be detected. The single-monitor method provides higher precision in visual inspection than does the separate-monitor method, and is a useful verification procedure.