ABSTRACT
Thermoluminescent (TL) response of trivalent praseodymium ion doped lanthanum aluminate (LaAlO3:Pr3+) obtained by Pechini method and Spray Dryer was studied. TL response of LaAlO3:Pr3+ powders submitted at 1600°C exhibited one peak centered at 157°C. Sensitivity of LaAlO3:Pr3+ was improved in around 90 times compared with undoped LaAlO3. TL response as a function of wavelength showed a maximum in 230nm. Dosimetric characteristics of LaAlO3:Pr3+ under UVR radiation effects were analyzed. Evaluation of activation energy was obtained by Glow Fit v.1.3 software. Experimental results about thermoluminescent characteristics of LaAlO3:Pr3+ suggest as good candidate to be employed as a complementary thermoluminescent device with other TL phosphors as aluminum oxide.
ABSTRACT
This paper presents results of equivalent dose organ determining to both primary beam and scattered radiation in a computed tomography (CT) procedures. All measurements were carried out to abdomen and critical organ (gonads) area. Selected dosimeters showed a standard deviation of 4.1% below to the reference values established by international guide lines. The equivalent dose in gonads was 14.27 mGy.
Subject(s)
Pelvis/radiation effects , Thermoluminescent Dosimetry , Tomography, X-Ray Computed/methods , Abdomen/radiation effects , Gamma Rays , Humans , Phantoms, Imaging , Radiation Protection/methods , Scattering, RadiationABSTRACT
Se ha medido la dosis en la superficie de entrada de ojos, tiroides y gónadas en pacientes sometidos a estudio de radiografía de tele de tórax mediante dosimetría termoluminiscente. Se usaron 5 dosímetros en cada una de las exploraciones; encontrándose los siguientes rangos de dosis: 20 mGy a 350 mGy. En el caso de los pacientes pediátricos se propone incluir la información de las dosis recibidas en su cartilla de vacunación con el fin de hacer un seguimiento de los posibles efectos nocivos en su salud.
Doses have been measured at the entrance surface of eyes, thyroid and gonads in patients undergoing chest x-ray studies, using thermo-luminiscent dosimetry. Five dosimeters were used in each investigation, and doses ranged from 20 mGy to 350 mGy. In the case of pediatric patients, it is proposed that dose information from diagnostic examinations is included in the vaccination chart in order to correlate with findings at follow-up.
Subject(s)
Humans , Female , Infant, Newborn , Middle Aged , Thermoluminescent Dosimetry , Thyroid Gland , Gonads , Eye , Radiometry/methods , Radiation Dosage , Thyroid Gland/radiation effects , Gonads/radiation effects , Eye/radiation effects , Radiation Protection/methods , Radiography, ThoracicABSTRACT
Thermoluminescent response of LiF:Mg,Cu,P+PTFE under clinical photon irradiation was obtained. Thermoluminescent dosimeters (TLDs) were irradiated for determining entrance surface dose (ESD) in a solid water phantom when using standard clinical adult treatment protocols. A Monte Carlo simulation of photon interaction with matter was performed and absorbed dose determined. ESD calculated by MCNPX code was greater than those determined by direct measurements in phantom. The results obtained open the possibility for using this material as a TLDs in medical accelerators.
Subject(s)
Models, Statistical , Monte Carlo Method , Thermoluminescent Dosimetry/instrumentation , Computer Simulation , Photons/therapeutic use , Protons , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Hafnium oxide (HfO(2)) films were deposited by the ultrasonic spray pyrolysis process. The films were synthesized from hafnium chloride as raw material in deionized water as solvent and were deposited on corning glass substrates at temperatures from 300 to 600 degrees C. For substrate temperatures lower than 400 degrees C the deposited films were amorphous, while for substrate temperatures higher than 450 degrees C, the monoclinic phase of HfO(2) appeared. Scanning electron microscopy showed that the film's surface resulted rough with semi-spherical promontories. The films showed a chemical composition close to HfO(2), with an Hf/O ratio of about 0.5. UV radiation was used in order to achieve the thermoluminescent characterization of the films; the 240 nm wavelength induced the best response. In addition, preliminary photoluminescence spectra, as a function of the deposition temperatures, are shown.
Subject(s)
Hafnium/chemistry , Luminescent Measurements/methods , Membranes, Artificial , Oxides/chemistry , Thermography/methods , Hafnium/radiation effects , Oxides/radiation effects , Temperature , Ultraviolet RaysABSTRACT
The uptake of the rhenium-188 (188Re(V)-DMSA) complex of dimercaptosuccinic acid by cervical carcinoma cells in nude mice was evaluated. The pharmacokinetics and dosimetry calculations in normal rats were also evaluated. The images obtained in mice did not show significant accumulation in metabolic organs and the biodistribution studies showed that 3.52 +/- 0.76% of the injected activity per gram (n = 4) was taken up by the tumor. This percentage produces a cumulated activity of 35.63 +/- 8.40 MBq h and an equivalent dose per injected activity of 260 +/- 8.91 mSv/MBq. Pharmacokinetics and dosimetry of the 1887e(V)-DMSA complex indicate that this radiopharmaceutical could be evaluated in patients with soft tissue tumors, since the risk of radiation damage to the kidney or red bone marrow could not be an obstacle for its application in therapeutic nuclear medicine.
Subject(s)
Organometallic Compounds/pharmacokinetics , Radioisotopes/pharmacokinetics , Radiopharmaceuticals/pharmacokinetics , Rhenium/pharmacokinetics , Succimer/pharmacokinetics , Uterine Cervical Neoplasms/metabolism , Uterine Cervical Neoplasms/radiotherapy , Animals , Female , HeLa Cells , Humans , Mice , Mice, Nude , Organometallic Compounds/administration & dosage , Organometallic Compounds/therapeutic use , Radiation Dosage , Radioisotopes/administration & dosage , Radioisotopes/therapeutic use , Radiopharmaceuticals/administration & dosage , Radiopharmaceuticals/therapeutic use , Rats , Rats, Wistar , Rhenium/administration & dosage , Rhenium/therapeutic use , Succimer/administration & dosage , Succimer/therapeutic use , Tissue DistributionABSTRACT
Information about the time that has elapsed since an external radiation exposure is useful in order to determine the time of occurrence of an abnormal exposure in personal and accidental dosimetry is presented. This information can be obtained from certain irradiated thermoluminescent dosimeters. A computational method based on decay rates of thermoluminescence glow peaks has been used to estimate a range of suitable values of trap lifetimes of low temperature glow peaks. This provides a basis for the selection of an appropriate thermoluminescent material to assess not only the absorbed dose from a radiation exposure, but also the elapsed time. Experimental studies have been used to obtain additional information on decay rates as a function of energy, temperature and absorbed dose.
