RESUMEN
Therapeutic assessment with fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is sometimes problematic after radiation therapy. Herein we describe a patient with acute radiation-induced hepatitis in which PET showed dose-dependent FDG uptake. A 50-year-old man underwent FDG PET for staging of esophageal cancer. Chemoradiotherapy was delivered concurrently with a radiation field that expanded from the esophagus into the upper stomach to cover metastasis of the gastric wall. The patient also underwent FDG PET 26 days and 4 months after chemoradiotherapy to evaluate the therapeutic effect. Twenty-eight days after chemoradiotherapy, hematochemistry revealed elevated hepatic enzymes and postcontrast computed tomography showed band-like hypoattenuation in the liver with parenchymal swelling corresponding to the radiation field. FDG PET performed 26 days after chemoradiotherapy showed a wedge-shaped hypermetabolic area in which the degree of FDG uptake correlated with the prescribed radiation dose. Follow-up PET 4 months after therapy showed no abnormal uptake in the liver. Acute radiation-induced hepatitis can be a potential cause of false-positive findings of malignancy on FDG PET scans, and PET images should carefully be compared with the distribution of prescribed dose. Threshold dose might be higher for metabolic changes than for morphologic changes.
Asunto(s)
Fluorodesoxiglucosa F18/farmacocinética , Hepatitis/etiología , Hígado/metabolismo , Tomografía de Emisión de Positrones/métodos , Traumatismos por Radiación/diagnóstico por imagen , Radiofármacos/farmacocinética , Enfermedad Aguda , Antineoplásicos/uso terapéutico , Terapia Combinada , Docetaxel , Relación Dosis-Respuesta en la Radiación , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/radioterapia , Hepatitis/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias/métodos , Traumatismos por Radiación/metabolismo , Taxoides/uso terapéuticoRESUMEN
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.
Asunto(s)
Fraccionamiento de la Dosis de Radiación , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Radioterapia Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/métodos , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Estudios Prospectivos , RadiocirugiaRESUMEN
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.
Asunto(s)
Neoplasias Pulmonares/radioterapia , Pulmón/fisiopatología , Técnicas Estereotáxicas , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Femenino , Volumen Espiratorio Forzado , Humanos , Neoplasias Pulmonares/fisiopatología , Masculino , Persona de Mediana Edad , Capacidad de Difusión Pulmonar , Pruebas de Función Respiratoria , Factores de Tiempo , Capacidad Pulmonar Total , Capacidad VitalRESUMEN
OBJECTIVE: We studied the serial changes and CT manifestations of pulmonary radiation injury after hypofractionated stereotactic radiation therapy for peripheral small lung tumors. SUBJECTS AND METHODS. Hypofractionated stereotactic radiation therapy was applied to 20 patients with proven primary (n = 11) or metastatic (n = 9) lung cancer, for a total of 22 lesions of 3 cm or less in diameter located within 3 cm from the parietal pleural surface. Follow-up CT was scheduled at 1 and 3 months, and every 3 months thereafter. RESULTS: Ground-glass opacities were observed around four (18%) of 22 lesions at 3-6 months. The opacities nearly corresponded to the planned target volume, but half of them were unevenly distributed. Ground-glass opacities gradually disappeared or evolved into dense consolidation while shrinking. Dense consolidations developed in 16 (73%) of 22 lesions, including seven in the center of the planned target volume and nine in the periphery of the planned target volume. Dense consolidations moved in six of these 16 lesions and gradually shrank, becoming fixed as solid or linear opacities approximately 12 months later. CONCLUSION: The pulmonary opacities observed after hypofractionated stereotactic radiation therapy for peripheral small lung tumors may not precisely correspond to the planned target volume (unlike those with conventional radiation therapy) and may change in shape and location dynamically during the first year. Knowledge of these findings is necessary to avoid misunderstandings concerning tumor regrowth or new tumors.
Asunto(s)
Neoplasias Pulmonares/radioterapia , Traumatismos por Radiación/diagnóstico por imagen , Traumatismos por Radiación/etiología , Tomografía Computarizada por Rayos X , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radioterapia/efectos adversos , Radioterapia/métodosRESUMEN
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.