An approximation for response function to γ-rays of NaI(Tl) detectors up to 1.5MeV

Cengiz, Ahmet

doi:10.1016/j.apradiso.2008.03.016

Cited by 11 publications

(5 citation statements)

References 23 publications

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“…Taking the midpoints of each sub-energy intervals E j (j¼1,2,3,…,n), one can distribute the photon number using the P/T ratio which is given in Table 1 and Gaussian distribution. The sampling of Gaussian distribution is done by the Monte Carlo method using the rejectionacceptance technique (Almaz, 2007;Cengiz, 2008). For each energy bin N y ¼ 10 7 events were generated.…”

Section: Function Name and Its Expression Parametersmentioning

confidence: 99%

Study of the continuous internal bremsstrahlung spectrum from 204Tl by using singular value decomposition

Almaz

2015

Applied Radiation and Isotopes

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Section: Function Name and Its Expression Parametersmentioning

confidence: 99%

Study of the continuous internal bremsstrahlung spectrum from 204Tl by using singular value decomposition

Almaz

2015

Applied Radiation and Isotopes

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“…Esse método de tratamento não exclui a necessidade de se realizar exposições do detector com fontes de radiação físicas pois certas propriedades do detector devem ser aplicadas à simulação para que esta e o método utilizado sejam validados [7,8].…”

Section: Materiais E Métodosunclassified

Estudo da função resposta de um detector cintilador de NaI(Tl)

Villa

Costa

2015

Braz. J. Rad. Sci.

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Nas medições de raios gama com cintiladores de NaI(Tl), os dados de saída dos detectores são espectros de altura de pulso, que correspondem a informações distorcidas sobre a fonte de radiação devido a diversos erros associados ao processo de cintilação do cristal e à eletrônica associada, ao invés de espectros de energia de fótons. Os espectros de altura de pulso são relacionados aos espetros de energia reais por meio da função resposta do detector cintilador de NaI(Tl). Neste trabalho foi estudada a função resposta para um cristal cilíndrico de NaI(Tl) de 7,62×7,62 cm (diâmetro×comprimento), pelo método de Monte Carlo, utilizando a ferramenta EGSnrc para modelar o transporte da radiação, combinado com medições experimentais. Foi obtida uma matriz resposta inversa, uniforme com a raíz quadrada da energia, que transforma o espectro de altura de pulsos em espectro de energia de fótons. Os resultados desta transformação de espectro de altura de pulsos para espectro de energia de fótons são apresentados, mostrando que metodologia empregada neste estudo é adequada.

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“…Scintillation detectors are calibrated by analyzing three aspects of the detector: energy, resolution, and efficiency [12]. Once the detector is fully calibrated, it can be used to perform gamma spectroscopic measurements in order to determine the activity of radioactive samples [13,14,15,16,17,18]. Ion chambers are calibrated by measuring a sample of the radiopharmaceutical in question with known activity, correcting for decay, and applying a calibration factor.…”

Section: Introductionmentioning

confidence: 99%

A Monte Carlo Method for Determining the Response Relationship between Two Commonly Used Detectors to Indirectly Measure Alpha Particle Radiation Activity

et al. 2019

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Using targeted ligands to deliver alpha-emitting radionuclides directly to tumor cells has become a promising therapeutic strategy. To calculate the radiation dose to patients, activities of parent and daughter radionuclides must be measured. Scintillation detectors can be used to quantify these activities; however, activities found in pre-clinical and clinical studies can exceed their optimal performance range. Therefore, a method of correcting scintillation detector measurements at higher activities was developed using Monte Carlo modeling. Because there are currently no National Institute of Standards and Technology traceable Actinium-225 (225Ac) standards available, a well-type ionization chamber was used to measure 70.3 ± 7.0, 144.3 ± 14.4, 222.0 ± 22.2, 299.7 ± 30.0, 370.0 ± 37.0, and 447.7 ± 44.7 kBq samples of 225Ac obtained from Oak Ridge National Lab. Samples were then placed in a well-type NaI(Tl) scintillation detector and spectra were obtained. Alpha particle activity for each species was calculated using gamma abundance per alpha decay. MCNP6 Monte Carlo software was used to simulate the 4π-geometry of the NaI(Tl) detector. Using the ionization chamber reading as activity input to the Monte Carlo model, spectra were obtained and compared to NaI(Tl) spectra. Successive simulations of different activities were run until a spectrum minimizing the mean percent difference between the two was identified. This was repeated for each sample activity. Ionization chamber calibration measurements showed increase in error from 3% to 10% as activities decreased, resulting from decreasing detection efficiency. Measurements of 225Ac using both detector types agreed within 7% of Oak Ridge stated activities. Simulated Monte Carlo spectra of 225Ac were successfully generated. Activities obtained from these spectra differed with ionization chamber readings up to 156% at 147.7 kBq. Simulated spectra were then adjusted to correct NaI(Tl) measurements to be within 1%. These were compared to ionization chamber readings and a response relationship was determined between the two instruments. Measurements of 225Ac and daughter activity were conducted using a NaI(Tl) scintillation detector calibrated for energy and efficiency and an ionization chamber calibrated for efficiency using a surrogate calibration reference. Corrections provided by Monte Carlo modeling improve the accuracy of activity quantification for alpha-particle emitting radiopharmaceuticals in pre-clinical and clinical studies.

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An approximation for response function to γ-rays of NaI(Tl) detectors up to 1.5MeV

Cited by 11 publications

References 23 publications

Study of the continuous internal bremsstrahlung spectrum from 204Tl by using singular value decomposition

Study of the continuous internal bremsstrahlung spectrum from 204Tl by using singular value decomposition

Estudo da função resposta de um detector cintilador de NaI(Tl)

A Monte Carlo Method for Determining the Response Relationship between Two Commonly Used Detectors to Indirectly Measure Alpha Particle Radiation Activity

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