RESUMEN
The effect of single and different split radiation doses with varying rates and time intervals was investigated in an experimental system in vivo using second generation isotransplants of two mouse mammary carcinomas. The changes in the growth delay time (GDT) and tumor control rate (TCR) were analyzed, and explained by a dose dependence of the repair of sublethal radiation damage, reoxygenation and cellular repopulation in the tumors. A direct relationship was found between the size of the first of two dose fractions and the time interval between two exposures at which treatment with split doses is most effective in delaying or preventing tumor growth. Multiple exposures to unequal dose fractions are more effective than to equal fractions with the same total dose.
Asunto(s)
Neoplasias Mamarias Experimentales/radioterapia , Animales , Relación Dosis-Respuesta en la Radiación , Electrones , Rayos gamma/uso terapéutico , Masculino , Ratones , Ratones Endogámicos C3H , Trasplante de Neoplasias , Dosificación Radioterapéutica , Factores de TiempoRESUMEN
The in vivo effects of buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) biosynthesis, on the cytotoxicity of cyclophosphamide (CYM), cisplatin (CDDP) and bleomycin (BLM), were examined by monitoring the changes of non-protein thiols (NPSH) in normal tissues and in the NFSa fibrosarcoma. We used the lung colony assay as a measure of tumor response and the spleen colony assay as a measure of normal tissue response to CYM. In this study, 5 mmol/kg of BSO was subcutaneously injected four times every 12 hr before administration of the above anti-neoplastic drugs. GSH levels in subcutaneous NFSa tumors decreased to 2% of the control 12 hr after the last administration of BSO, but in the bone marrow, had recovered to 41%. In the colony assays, BSO increased the anti-cancer effects of the three chemotherapeutic agents, but did not modify the bone marrow suppression by CYM. This finding was a result of the differential response of GSH depletion in the tumor and in the bone marrow. Our study demonstrates that BSO is an effective chemosensitizer of these drugs and may be of therapeutic value when used at an optimal interval.
Asunto(s)
Antineoplásicos/uso terapéutico , Metionina Sulfoximina/análogos & derivados , Neoplasias Experimentales/tratamiento farmacológico , Animales , Bleomicina/uso terapéutico , Butionina Sulfoximina , Cisplatino/uso terapéutico , Ciclofosfamida/uso terapéutico , Glutatión/metabolismo , Masculino , Metionina Sulfoximina/uso terapéutico , Ratones , Ratones Endogámicos C3H , Trasplante de NeoplasiasRESUMEN
The radiosensitizing effects of misonidazole (MISO) in combination with D,L-buthionine-S, R-sulfoximine (BSO), an inhibitor of glutathione (GSH) biosynthesis, were studied in NFSa tumors of C3H/He mice. The radiation response of tumors was assayed by the tumor growth delay time. The GSH contents in tissues were assayed by high performance liquid chromatography (HPLC). GSH content in the tumors decreased to the minimum level (45% of the control), and then gradually recovered to 75% of the control, respectively, 12 and 24 hr after the intraperitoneal injection of 5 mmole/kg BSO. On the other hand, the maximum non-protein sulfhydryl (NPSH) depletion (29% of the control) in the liver of tumor bearing mice was achieved 6 hr after the administration of the same dose of BSO, but fully recovered 24 hr later. When 5 mmole/kg BSO was injected repeatedly 4 times at an interval of 6 hr, GSH content in the tumors decreased to 19% of the control 24 hr after the first injection of BSO. The radiosensitizing effect of 0.5 mmole/kg MISO was markedly increased by this BSO treatment. The enhancement ratio (ER) of this combined treatment was 1.93. On the other hand, ERs of 1.44 and 1.16 were obtained for MISO (0.5 mmole/kg) and for 4 injections of BSO (5 mmole/kg) in combination with radiation, respectively. Although a considerable increase in the radiosensitizing efficiency of MISO in vivo by the treatment with BSO was found without any notable side effects of the combination, more studies on toxicities are needed to get a definite conclusion on the clinical applicability of the combination.
Asunto(s)
Glutatión/fisiología , Metionina Sulfoximina/análogos & derivados , Misonidazol/uso terapéutico , Neoplasias Experimentales/radioterapia , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Animales , Butionina Sulfoximina , Terapia Combinada , Quimioterapia Combinada , Metionina Sulfoximina/uso terapéutico , Ratones , Neoplasias Experimentales/tratamiento farmacológicoRESUMEN
A series of 3-nitro-1,2,4-triazole derivatives bearing various types of side chain (R) at the N1-position (AK-2000 series) were synthesized and their radiosensitizing effect and toxicity in vitro and in vivo were investigated, in comparison with those of Misonidazole (MISO), SR-2508, and RSU-1069. Of the fifteen 3-nitrotriazoles tested, all had sensitizing effects in vitro on hypoxic V79 cells. Also, all but one had definite effects on solid EMT6/KU and SCCVII tumors in vivo. For many of the triazole compounds, the degree of radiosensitization in vitro and in vivo appeared identical. However, they were generally less efficient, both in vitro and in vivo, than the corresponding 2-nitroimidazoles, whereas their aerobic cytotoxicity and toxicity to mice (LD50/7) were comparable to those of the 2-nitroimidazoles. Considering the sensitizing effect and toxicity, AK-2123 (R = CH2CONHC2H4OCH3) may be as useful as MISO, but none of the triazoles have been proved to be superior to SR-2508.
Asunto(s)
Neoplasias Experimentales/radioterapia , Nitroimidazoles/farmacología , Fármacos Sensibilizantes a Radiaciones/farmacología , Triazoles/farmacología , Animales , Terapia Combinada , Cricetinae , Femenino , Técnicas In Vitro , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Trasplante de Neoplasias , Neoplasias Experimentales/tratamiento farmacológico , Nitrocompuestos/farmacología , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Fármacos Sensibilizantes a Radiaciones/toxicidadRESUMEN
The effects of Fluosol-DA 20% (FDA) and carbogen (95% O2/5% CO2) on radiosensitivity of the three experimental tumors, SCC VII tumor, RIF-I tumor, and transplanted mammary tumor of C3H/He mouse, subcutaneously inoculated in the leg were examined. The effect of FDA plus carbogen, and carbogen alone on radiosensitivity of SCC VII and RIF-I tumors was tested using the in vivo-in vitro assay. The growth curves were obtained for both SCC VII tumor and transplanted mammary tumor. The effect of the combination of FDA and carbogen was only observed in the transplanted mammary tumor. In the other two tumors, only the effect of inspiring carbogen was observed. We concluded that the effect of FDA on the radiosensitivity of experimental tumors varies with the kind of tumor systems.
Asunto(s)
Fluorocarburos/uso terapéutico , Neoplasias Experimentales/radioterapia , Fármacos Sensibilizantes a Radiaciones , Animales , Dióxido de Carbono/uso terapéutico , Combinación de Medicamentos/uso terapéutico , Derivados de Hidroxietil Almidón , Ratones , Ratones Endogámicos C3H , Trasplante de Neoplasias , Oxígeno/uso terapéuticoRESUMEN
We report the effect of human granulocyte colony-stimulating factor (hG-CSF) on the recovery from granulocytopenia induced by irradiation. Female 9-week old C3H/He mice were used. The irradiation schedule was as follows: Group 1 and 2 received whole-body irradiation of 1 Gy and 5 Gy, respectively, on day 0; Group 3 and 4 received whole-body irradiation of 0.5 and 1.0 Gy, respectively, for 5 consecutive days; Group 5 received upper hemibody irradiation of 3 Gy for 5 consecutive days. Daily subcutaneous injections of G-CSF (3 x 10(5) Unit/mouse) or 0.3 ml of saline to each group were started from the day after the first irradiation and continued for 18 days. Mice were sampled randomly from each group, and the total number of leukocytes, erythrocytes of peripheral blood, nucleated cells in femur, and spleen weight were counted and measured, respectively, on day 0, 3, 5, 7, 9, 12, and 18. The leukocyte counts decreased with an increase in radiation doses. In Group 1 and 2 mice, G-CSF enhanced the leukocyte count more than saline. In Group 3 mice, the recovery of leukocytopenia was facilitated by G-CSF, but in Group 4 mice, G-CSF had no effect on the leukocyte count decrease or on leukocytopenia recovery. In Group 5 mice, G-CSF greatly affected leukocytopenia recovery. Increase in spleen weight paralleled the peripheral leukocyte count. Daily administration of recombinant hG-CSF accelerated the granulocytopenia recovery which was induced by irradiation, and it may be a useful therapeutic agent for treating myelosuppressive cases.
Asunto(s)
Agranulocitosis/tratamiento farmacológico , Factores Estimulantes de Colonias/uso terapéutico , Traumatismos Experimentales por Radiación/tratamiento farmacológico , Agranulocitosis/etiología , Animales , Femenino , Factor Estimulante de Colonias de Granulocitos , Granulocitos , Ratones , Ratones Endogámicos C3H , Traumatismos Experimentales por Radiación/complicaciones , Proteínas Recombinantes , Irradiación Corporal TotalRESUMEN
A real time CT-linked 3-D treatment planning system, called a CT simulator, has been developed. The basic system consists of a CT scanner, a multi-image display component, a treatment planning device with real time visual optimization, and a laser beam projecting component. All the components are connected on line. The system can be conveniently used for 3-D planning and simulation for radiation therapy within a reasonably short period of time.
Asunto(s)
Simulación por Computador , Sistemas de Computación , Planificación de la Radioterapia Asistida por Computador , Radioterapia Asistida por Computador , Tomografía Computarizada por Rayos X , HumanosRESUMEN
We have performed radiotherapy treatment planning (RTP) with a new system called CT simulator in 72 patients. With the system, RTP is performed with the patient lying on the CT couch within a short period of time. All the CT images scanned were immediately transported to the multi-image monitors and to the treatment planning device. Radiotherapy treatment planning could be performed not only at the beam center but also at any CT slice. Using a laser-beam field projector, field outlines were drawn over the patient's skin. In clinical use, the system was useful for cases in which a target lies adjacent to dose limiting organs, cases with a complicated target shape, cases with complicated dose distribution curves, and cases treated with tangential fields. This system enables us to make optimum use of CT information and to make accurate 3-dimensional treatment planning programs.
Asunto(s)
Simulación por Computador , Sistemas de Computación , Neoplasias/radioterapia , Planificación de la Radioterapia Asistida por Computador , Radioterapia Asistida por Computador , Tomografía Computarizada por Rayos X , Humanos , Neoplasias/diagnóstico por imagenRESUMEN
PURPOSE: The results of three-dimensional treatment planning using a computed tomography simulator were evaluated in patients with maxillary cancer. METHODS AND MATERIALS: Treatment planning was done in 25 patients using an x-ray simulator and plain x-ray films (1979-1982, group 1) in 34 patients using an x-ray simulator and computed tomography films (1983-1987, group 2), in 24 patients using a computed tomography simulator (1988-1992, group 3). The number of patients with Stage IV disease increased in the order of group 1 to group 3. RESULTS: The average radiation field was smallest in group 3 (66.5 cm2) followed by group 2 (67.4 cm2) and group 1 (72.9 cm2). A radiation dose of more than 30 Gy to the lens of the effected side was delivered to 13% of group 3, 44% of group 2, and 44% of group 1. The dose to the lens on the uneffected side was zero in 56% of group 1, 74% of group 2, and 96% of group 3. A long-term decrease in visual activity on the effected side occurred in 11% of group 3, 32% of group 2, and 44% of group 1. However, a significant increase in survival was only noted between groups 1 and 2, because the three population of patients were different. CONCLUSION: The three-dimensional treatment planning results in a better treatment than two-dimensional treatment planning as measured by complication rates and field sizes.
Asunto(s)
Neoplasias Maxilares/radioterapia , Radioterapia Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/métodos , Anciano , Simulación por Computador , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dosificación Radioterapéutica , Análisis de SupervivenciaRESUMEN
Large radiosensitization of C3H/He mouse mammary tumors was obtained with the combination of a non-protein sulfhydryl (NPSH) depletor, diethyl maleate (DEM), and misonidazole (MISO), compared with MISO alone over a range of MISO dose. The difference in enhancement ratios (ER's) for these two treatments was especially prominent at small MISO doses. ER's of 2.06 and 1.44 were obtained, respectively, by combined treatment with DEM (760 mg/kg) and MISO (100 mg/kg) or treatment with MISO alone. Radiosensitization of tumors by DEM alone was observed for doses over 600 mg/kg. When DEM was combined with MISO (100 mg/kg), ER's of the combination were larger than that of MISO alone, for doses over 400 mg/kg of DEM. Similarly, in case of DEM plus MISO (300 mg/kg), the ER's became larger than MISO alone, for doses over 200 mg/kg of DEM. The NPSH content in untreated tumors was 1.08 mmole/kg on the average and no changes in NPSH content was observed after MISO treatment. DEM treatment markedly reduced the NPSH content of tumors as a function of DEM dose and this decrease in NPSH was not significantly affected by MISO treatment. Tumor NPSH was reduced to 24% or less of control by administration of 760 mg/kg of DEM with or without MISO. These results are consistent with competition theory of NPSH and electron affinic radiosensitizers.
Asunto(s)
Maleatos/uso terapéutico , Neoplasias Mamarias Experimentales/radioterapia , Misonidazol/uso terapéutico , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Animales , Terapia Combinada , Quimioterapia Combinada , Femenino , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Ratones , Ratones Endogámicos C3HRESUMEN
PURPOSE: To introduce the process of developing an integrated radiotherapy network. METHODS AND MATERIALS: We developed a new radiotherapy treatment-planning system in 1987 that we named the Computer Tomography (CT) simulator. CT images were immediately transported to multiimage monitors and to a planning computer, and treatment planning could be performed with the patient lying on the CT couch. The results of planning were used to guide a laser projector, and radiation fields were projected onto the skin of the patient. Since 1991, an integrated radiotherapy network system has been developed, which consists of a picture archiving and communicating system (PACS), a radiotherapy information database, a CT simulator, and a linear accelerator with a multileaf collimator. RESULTS: Clinical experience has been accumulated in more than 1,000 patients. Based on our 7 years of experience, we have modified several components of our original CT simulator and have developed a second generation CT simulator. A standard protocol has been developed for communication between the CT scanner, treatment planning computer, and radiotherapy apparatus using the Ethernet network. As a result, treatment planning data can be transported to the linear accelerator within 1 min after completion of treatment planning. CONCLUSION: This system enables us to make optimal use of CT information and to devise accurate three-dimensional (3D) treatment-planning programs. Our network also allows for the performance of fully computer-controlled dynamic arc conformal therapy.
Asunto(s)
Redes de Comunicación de Computadores/organización & administración , Simulación por Computador , Sistemas de Información Radiológica/organización & administración , Planificación de la Radioterapia Asistida por Computador/organización & administración , Tomografía Computarizada por Rayos XRESUMEN
The first and multiple scattered radiations of 60Co gamma rays and 10 MV X-rays were measured using an ionization chamber, and the values obtained were compared with the calculated values. The experimental values of the angle distributions of the first scattered photons from tissue-equivalent materials in free space agreed well with the theoretical values calculated from the Klein-Nishina probability in the compton scattering process. However, the scattered radiation in phantoms was not represented by only the first scatter components. The results indicate that the weighting factor of all scattered radiations in the calculated three-dimensional dose distribution can be set by the inverse square correction for the distance from the scattering point to the reference point within an accuracy required in clinical dosimetry. The present method provides a simple and practical approach to obtaining the computation speed in three-dimensional treatment planning.
Asunto(s)
Radioisótopos de Cobalto , Planificación de la Radioterapia Asistida por Computador , Radioterapia Asistida por Computador , Radioterapia de Alta Energía , Humanos , Radiometría/instrumentación , Dispersión de RadiaciónRESUMEN
The radiosensitizing efficacy of SR-2508, a new 2-nitroimidazole, which is less neurotoxic than misonidazole (MISO) was studied using transplantable mammary carcinoma of C3H/He mice. Tumor responses to treatments were evaluated by growth-delay time assay. In single irradiations, the enhancement ratios of 0.5 mmole/kg of MISO and 1.5 mmole/kg of SR-2508, which were equitoxic to C3H/He mice, were 1.42 and 1.84 respectively. In fractionated irradiations with three fractions over two days or five fractions over four days, the enhancement ratios of 1.5 mmole/kg of SR-2508 were 1.40 and 1.34 respectively. On the other hand the enhancement ratios of MISO at the above mentioned dose in respective fractionated irradiations were 1.15 or 1.11. SR-2508 is considered promising as a hypoxic cell radiosensitizer for clinical use.
Asunto(s)
Neoplasias Mamarias Experimentales/radioterapia , Misonidazol/uso terapéutico , Nitroimidazoles/uso terapéutico , Animales , Etanidazol , Femenino , Ratones , Ratones Endogámicos C3H , Trasplante de Neoplasias , Fármacos Sensibilizantes a Radiaciones , Dosificación Radioterapéutica , Radioterapia de Alta EnergíaRESUMEN
Recent advances in radiotherapy are remarkable. The main reason for the development of radiotherapy is the contribution of therapy equipment. In present paper, histories, present status and the future of radiotherapy equipment are explained and discussed.
Asunto(s)
Braquiterapia/instrumentación , Radioterapia/instrumentación , Braquiterapia/tendencias , Radioterapia/tendenciasAsunto(s)
Traumatismos Experimentales por Radiación/prevención & control , Protectores contra Radiación , Piel/efectos de la radiación , Superóxido Dismutasa/farmacología , Animales , Relación Dosis-Respuesta en la Radiación , Inyecciones Intraperitoneales , Ratones , Superóxido Dismutasa/administración & dosificaciónRESUMEN
In radiotherapy planning it is essential to compose dose distribution curves on a transverse section of patient. For this purpose we have developed the radiotherapy planning system using a computer (Modulex), in which CT images and CT numbers were input on off-line with a CT magnetic tape, CT numbers were converted into relative electron densities and then, dose distribution curves calculated were output directly on CT images. One of problems lying in this system was that the three-dimensional dose distribution had to be surmised with a couple of two-dimensional ones. Clinical application of this system has been applied to planning of intraoperative radiotherapy that was considered to provide ideal dose distributions, and its effectiveness was discussed.
Asunto(s)
Neoplasias/radioterapia , Dosificación Radioterapéutica , Computadores , Humanos , Periodo Intraoperatorio , Planificación de Atención al Paciente/métodos , Tomografía Computarizada por Rayos XRESUMEN
Chinese hamster cells (V79) and glutathione-proficient (GSH+/+) and glutathione-deficient (GSH-/-) human fibroblasts were treated with a glutathione (GSH)-depleting agent buthionine sulphoximine (BSO) and the hypoxic radiosensitizer misonidazole (MISO), separately or in combination. Subsequently, the cells were exposed to X-rays. Determination of the yield of single-strand DNA breaks (ssb) immediately after irradiation indicated no effect of BSO or MISO treatment when radiation exposure was made aerobically. Assuming that ssb determined immediately after irradiation reflects mainly the effect of radical processes, the results obtained with BSO and MISO, singly and in combination, agreed well with the predictions of a modified version of the 'competition model' using V79 and GSH+/+ cells. Some results obtained with GSH-/- cells could not be so explained.
Asunto(s)
Glutatión/fisiología , Metionina Sulfoximina/análogos & derivados , Misonidazol/farmacología , Nitroimidazoles/farmacología , Tolerancia a Radiación , Animales , Butionina Sulfoximina , Línea Celular , Cricetinae , Cricetulus , ADN de Cadena Simple/efectos de la radiación , Relación Dosis-Respuesta a Droga , Fibroblastos/efectos de los fármacos , Fibroblastos/efectos de la radiación , Humanos , Técnicas In Vitro , Metionina Sulfoximina/farmacologíaRESUMEN
An intracellular radiation-chemical reaction scheme is tested in which solute and solvent radicals R. react with non-target molecules Sa (scavengers) or with target molecules (presumed to be DNA) to produce target radicals T., which may also be produced by direct ionization of DNA. The rate of target radical decomposition to become 'uncommitted damage' that the cell may repair is affected by the concentration of oxygen (O2), thiols (S) and electronaffinic sensitizers (F), which compete with one another to form, respectively, target products TO2, TS and TF. This uncommitted damage is then subject to biochemical modification, including molecular repair, by the cell. The rate equations for this competing reaction scheme were written and programmed for computer simulations of changes in oxygen, thiol and electronaffinic sensitizer concentrations. A reaction scheme that also includes some non-radical target damage was also simulated. Simulations were made using available experimental data concerning intranuclear concentrations and reaction rate constants, respectively, ko, ks and k1 for the reactions T. + O2----TO2, T. + S----TS and T. + F----TF, which produce uncommitted chemical damage. Experimental data on strand-break induction in glutathione-proficient and glutathione-deficient cells, in cells treated with thiol active agents, and in cells treated with hypoxic sensitizers, along with the computer simulations, generally agree that thiol molecules can react with target radicals to reverse T. in competition with O2 and/or electronaffinic sensitizers. Forward reaction rate constants ko, ks (dithiothreitol), ks (glutathione) and k1 (misonidazole) in the approximate ratio 10:0.3:0.02:0.4 satisfied the above reaction scheme, and approximately 5 per cent non-radical target molecule damage could be included with satisfactory agreement with experimental data.