Radiation total dose

Outgassing Data for Selecting Spacecraft Materials, NASA Reference Publication 1124, Rev. 4, Goddard Space Flight Center (Jun. 1997) and http //outgassing.nasa.gov. Ionizing Radiation (Total Dose) Test Procedure, Method 1019.6 MIL-STD-883F. Mar. 

Ionizing Radiation (Total Dose) Test Procedure, Method 1019.6 MIL-STD-883F (Mar. 2003)... 

Specimens used in tests were sections of cables with PVC outer coating. PVC was plasticized with DOF softener. The materials considered were exposed to the radiation and thermal aging. The samples have been irradiated at room temperature by hard gamma rays with 10 rad/sec dose power. A number of samples had been heated for long different times at 90°C. Besides a special specimens were cut out from outer coating for test on tensile machine like "Instron". The total doses of irradiation, times of heating and elongations at break obtained with "Instron" are listed in Table 1. 

Solution polyacrylamides can also be prepared at high polymer soHds by radiation processes (80,81). Polyacrylamides with molecular weights up to 20 million can be prepared by inradiation of acrylamide and comonomers in a polyethylene bag with cobalt-60 gamma radiation at dose rates of 120-200 J/kg-h. The total dose of radiation is controlled to avoid cross-linking. 

Ground radiation is from deposited radioactive particles. The deposition rate from a radioactive cloud without rain (dry deposition) is so low that the ground radiation dose is about the same as the inhalation dose. A heavy rain, however, may wash out enough particles from the plume to make ground radiation the dominant contributor to the total dose in a limited area. Rain will also attenuate radiation by leaching the radioactivity to be shielded by the soil and by moving it to streams for further removal. 

The dose and dose rate of irradiation are important factors in any radiation grafting system. In the direct method the total dose determines the number of grafting sites, while the dose rate determines the number of grafting sites, and the dose rate determines the length of the grafted branches. The length of the branches is also con-... 

Male infertility may result from cancer surgery, radiotherapy, hormonal imbalances, or damage of germinal stem cells. Testicular damage from radiotherapy depends on the treatment field, total dose, and fractionation schedule. Depending on the radiation, sperm counts may return to pretreatment levels in 10 to 24 months after therapy or maybe permanent in 80% of men after total-body irradiation for transplant. 

Standard doses of radiotherapy for HL generally total 3600 cGy to each field in daily fractions of 180 cGy over 4 weeks. Clinically involved areas are given boost doses of 550 to 900 cGy in three to five fractions, resulting in a total dose to the involved area of upwards of 4500 cGy. Radiation maybe given as consolidation following completion of a complete course of chemotherapy in patients with advanced HL.13,14 This treatment typically is reserved for patients who have an unconfirmed response to chemotherapy or who have bulky disease on presentation. 

Cumulative Dose (Radiation)—The total dose resulting from repeated or continuous exposures to radiation. 

The incidence of ovarian tumors in mice, guinea pigs, and rabbits increased after 3 years of chronic irradiation at doses as low as 1.1 mGy daily (Lorenz et al. 1954). Unlike other tumors, the induction of ovarian tumors depended on a minimum total dose and seemed to be independent of a daily dose (Lorenz et al. 1954). Radiation-induced neoplastic transformation of hamster cells may be associated initially with changes in expression of the genes modifying cytoskeletal elements (Woloschak et al. 1990b). 

Total beta and gamma radiation Total annual whole-body dose equivalent, or dose 3... 

Tests of a graphite-reinforced polyimide composite (C6000/PMR15) did not show any effect of radiation exposure (1 MEV electrons 6x109 rad total dose) on the thermal expansion behavior (14). DMA curves for unirradiated and irradiated composites were essentially identical over the temperature range of the thermal expansion measurements. 

The effect of radiation on the thermal expansion of this toughened composite (T300/CE 339) is shown (191 in Figure 24. The thermal strains measured during the cool-down portion of the first thermal cycle (cooling from RT to -150°C) are shown for the baseline composite (no radiation exposure) and for samples exposed to total doses as high as 10 0 rads. Radiation levels, as low as 10 rads... 

Specific health effects resulting from an acute dose appear only after the victim exceeds a dose threshold. That is, the health effect will not occur if doses are below the threshold. (Note that this is significantly different from the LNT model used to predict stochastic effects.) After reaching the acute dose threshold, a receptor can experience symptoms of radiation sickness, also called acute radiation syndrome. As shown in Table 3.2, the severity of the symptoms increases with dose, ranging from mild nausea starting around 25-35 rad (0.25-0.35 Gy) to death at doses that reach 300-400 rad (3-4 Gy). Table 3.2 shows that the range of health effects varies by both total dose and time after exposure. 

Dosimetry is an autoradiographic technique to measure the total dose of radiation received by a worker ov -r a period of time. 

Radiation (total body irradiation or fractionated abdominal radiation) Adult dose of 2 mg once daily. Two 1 mg tablets or 10 mL of oral solution are taken within 1 hour of radiation. 

Takeda et al. (64) performed a phase I/II study consisting of low-dose CDDP (6-10 mg/m2/d) and UFT (600 mg/d) combined with radiotherapy (50 Gy/25 fractions) as postoperative adjuvant therapy following curative resection for patients with nonsmallcell lung cancer (NSCLC). The combined therapy was well tolerated and resulted in a disease-free survival rate of 78% at 2 yr. Another study in a small number of patients with unresectable stage III nonsmall-cell lung cancer, UFT (400 mg/m2 on d 1-52) and CDDP (80 mg/m2 on d 8,29, and 50) were administered with radiation therapy (total dose of 60.8 Gy in 38 fractions on d 1-52). Among 17 evaluable patients, 94% (16 patients) achieved partial responses with median time to tumor progression of 30 wk, and the... 

The Southwest Oncology Group (SWOG) conducted a phase II trial with continuous thoracic radiation to a total dose of 61 Gy and simultaneous daily cisplatin (5 mg/m2) and found acceptable toxicity (130). Another trial utilized a split-course of thoracic radiation therapy to a total dose of 50 Gy and simultaneous daily continuous infusion cisplatin (5 mg/m2) and found a 35 % 2-yr survival rate with relatively mild toxicity (131). Weekly doses of carboplatin were administered with continuous thoracic irradiation to a total dose of 60 Gy in a phase II trial that resulted in a 45% response rate (132). 

Choy et al. have published two further phase II trials of concurrent paclitaxel and carboplatin. In both trials the two drugs were administered weekly with paclitaxel at a dose of 50 mg/m2 and carboplatin at a dose of 2 AUC. The first of these trials, LUN-56 (60), combined these two drugs with once daily radiation to adose of 66 Gy and the second trial, LUN-63 (61), used hyperfractionated radiation to a total dose of 69.6 Gy directed at the primary tumor. They have shown similar promising results in patient populations where 70% have stage IIIB disease. LUN-56, which enrolled40 patients, showed a 76% response rate and 1-, 2-, and 3-yr median survivals of 54,46, and 32% 43 patients were enrolled on LUN-63. In this trial there was a 79% response rate and a median survival of 14.3 mo. Encouraging 1- and 2-yr survivals of 61% and 35% were seen. 

Socinski et al. have reported on their phase I/II experience with dose-escalated thoracic radiation in the setting of a combined modality approach to locally advanced NSCLC (55,64). Two cycles of carboplatin and paclitaxel (AUC 6 and 225 mg/m2/3h q21d) were followed on d 43 by weekly carboplatin and paclitaxel (AUC 2 and 45 mg/ m2/3h x 6) and thoracic radiotherapy (TRT), 50 Gy was delivered to the prechemotherapy tumor volume and areas of suspected microscopic spread in the mediastinum with a 1.0-2.0 cm margin. Boost volumes included the primary tumor volume and all radiographically positive nodes with a 1.0 cm margin. The total dose of radiation was escalated through four cohorts of patients 60,66,70,74 Gy without reaching any of the planned toxicity endpoints. The overall response to the therapy was 50% (3% CR, 47%... 

Wright et al. from the Massachusetts General Hospital reported interesting results from their intensive trial of preoperative paclitaxel, cisplatin, and 5-fluorouracil with hyperfractionated radiation (total tumor dose of 58.5 Gy and 45 Gy to the mediastinum)... 

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