RESUMEN
PURPOSE: To evaluate the feasibility of using the da Vinci robotic system for radioactive seed placement in the wedge resection margin of pigs' lungs. METHODS AND MATERIALS: Video-assisted thoracoscopic wedge resection was performed in the upper and lower lobes in pigs. Dummy (125)I seeds embedded in absorbable sutures were sewn into the resection margin with the aid of the da Vinci robotic system without complications. In the "loop technique," the seeds were placed in a cylindrical pattern; in the "longitudinal," they were above and lateral to the resection margin. Orthogonal radiographs were taken in the operating room. For dose calculation, Variseed 66.7 (Build 11312) software was used. RESULTS: With looping seed placement, in the coronal view, the dose at 1 cm from the source was 97.0 Gy; in the lateral view it was 107.3 Gy. For longitudinal seed placement, the numbers were 89.5 Gy and 70.0 Gy, respectively. CONCLUSION: Robotic technology allows direct placement of radioactive seeds into the resection margin by endoscopic surgery. It overcomes the technical difficulties of manipulating in the narrow chest cavity. With the advent of robotic technology, new options in the treatment of lung cancer, as well as other malignant tumors, will become available.
Asunto(s)
Braquiterapia/métodos , Radioisótopos de Yodo/administración & dosificación , Pulmón , Robótica/métodos , Cirugía Torácica Asistida por Video , Animales , Estudios de Factibilidad , Neoplasias Pulmonares/radioterapia , PorcinosRESUMEN
Intravascular brachytherapy treatments of in-stent restenosis have been performed extensively using Ir-192 ribbon. Task Group 60 of the American Association of Physicists in Medicine (AAPM) recommends a dose reference point at 2 mm from the source center for these treatments. However, it is known that the source can be as close as 0.5 mm to the arterial wall if not centered in the lumen. Therefore, the source dosimetry needs to be characterized at these close distances to accurately determine the amount of dose delivered for noncentered cases. In this paper, we report the verification of the dose distributions around Ir-192 seed sources at radial distances from 0.5 mm to 6 mm using GAFCHROMIC film. We evaluated an Ir-192 single seed source and a train of 6 seeds spaced 1 mm apart enclosed in a nylon ribbon. Each source was placed in a homogeneous solid water phantom directly below a stack of GAFCHROMIC films (MD-55-2). The calibration curve of the lot of films used in the experiment was established for Ir-192 by exposing a set of calibration films, one at a time, to an Ir-192 high dose rate (HDR) source. All films were scanned 5 or more days after exposure with a Lumisys Model 150 microdensitometer. The data were acquired and evaluated using RIT113 (Radiological Imaging Technology) software and analyzed using Excel and IDL (Interactive Data Language) software. Isodose curve plots in the plane containing the source's longitudinal axis and dose rate plots in the radial direction were obtained. For both configurations, the dose rates along the transverse axes agree to within the margin of error with previous Monte Carlo results. The isodose curve plots display hot spots near the seed ends, which is consistent with the leakage of beta particles and electrons from the unsealed seed ends as predicted with Monte Carlo calculations.
Asunto(s)
Radioisótopos de Iridio/uso terapéutico , Radiometría/métodos , Película para Rayos X , Braquiterapia/métodos , Calibración , Densitometría , Relación Dosis-Respuesta en la Radiación , Electrones , Humanos , Método de Montecarlo , Radiometría/instrumentación , Programas InformáticosRESUMEN
The long-term survival probability for Hungarian lung cancer patients is 10% worse than the best results published in the most highly developed countries (the mean 5-year survival probability in Hungary is 5%, in contrast with the 15% survival probability in the USA). On the basis of the international recommendations and personal experience, an attempt was made to formulate the guidelines for radiotherapy as one of the fundamental non-small cell lung cancer (NSCLC) treatment modalities for national use. An expert panel was set up comprising physicians from 6 radiotherapeutic centers (the National Institute of Oncology / Semmelweis University, Budapest; the Beth Israel Medical Center, New York; the University of Kaposvár; the University of Essen; the University of Debrecen; and the County Hospital of Gyula). Experts in two important medical fields closely related to radiotherapy (surgery and diagnostic imaging) were also engaged in the elaboration of the manuscript. Discussion of the most important principles of the radiotherapy and an overview of the prognostic factors was followed by a critical analysis of the protocols applied in the radiotherapy of Hungarian NSCLC patients during recent decades. The new guidelines suggested for the radiotherapy of NSCLC are presented separately for the postoperative period, marginally resectable tumors, and the aggressive or non-aggressive radiotherapy of inoperable tumors. Detailed accounts are given of the techniques of external irradiation and brachytherapy, and of the acute and late radiation-induced damage of normal tissues. The authors believe that this document may be instrumental in improving the survival index of Hungarian NSCLC patients in the near future.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Neoplasias Pulmonares/radioterapia , Traumatismos por Radiación/etiología , Braquiterapia , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Fraccionamiento de la Dosis de Radiación , Humanos , Hungría/epidemiología , Metástasis Linfática , Estadificación de Neoplasias , Pronóstico , Traumatismos por Radiación/prevención & control , Radioterapia/efectos adversos , Radioterapia/métodos , Dosificación Radioterapéutica , Medición de Riesgo , Factores de Riesgo , Índice de Severidad de la Enfermedad , Tasa de SupervivenciaRESUMEN
Non-small-cell lung cancer (NSCLC) has one of the highest death rates among the various forms of cancer. In attempts to improve on this unsatisfactory outcome, different radiation schedules and chemo-therapy agents have been examined in phase II or III studies. These have led to modest improvements in local control and survival, but combined therapies are associated with substantial hematologic toxicity. In this phase II study, 80 consecutive stage IIIA or IIIB NSCLC patients were treated with concomitant chemotherapy and twice-a-day irradiation in a total dose of 60 Gy in 1.5 Gy fractions. Patients scheduled for surgery received 45 Gy only. Paclitaxel (30 mg/m 2 ) on days 1-4 and cisplatin (100 mg/m 2 ) on day 5 were administered in the first and fourth weeks of treatment. Granulocyte colony stimulating factor (30 ng/m 2 ) was given on days 10-15. The local control, the 1- and 2-year survival rates and the occurrence of acute hematologic toxicity in the non-surgically treated patients were examined. Fifty-two patients were treated without and 28 with surgery. Among the non-surgically treated cases, 43 were evaluable for response and 47 for acute toxicity during a median follow-up of 22 months. The rate of local control was 65% (28/43), and the 1- and 2-year survival rates proved to be 68% and 48%, respectively, with a median survival of 28 months. Severe acute grade 3-4 toxicities included grade 4 leukopenia in 6 cases (13%), grade 3 leukopenia in 4 cases (9%), grade 3 esophagitis in 3 cases (6%) and grade 3 anemia in 3 cases (6%). Our results and the relevant data from the literature support the application of twice-a-day irradiation with concomitant chemotherapy in stage IIIA and IIIB NSCLC. Local control and survival were improved relative to once-a-day irradiation with sequential or concomitant chemotherapy.