Comparison of methods to determine accurate dose calibrator activity measurements

Strigari, Lidia; Benassi, Marcello; Felice, P. De; D’Andrea, M.; Fazio, A.; Nocentini, S.; d’Angelo, A.; Ceccatelli, A.

doi:10.1186/1756-9966-27-14

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…The 223 Ra activity was measured using the radionuclide calibrator PET DOSE (Comecer) following the procedures in [ 13 , 14 ]. For each patient, activity time curves were determined using antero-posterior and postero-anterior 30 min planar images acquired at 2–4, 18–24 h and 7 days after the each 223 Ra administration.…”

Section: Methodsmentioning

confidence: 99%

The role of dosimetry and biological effects in metastatic castration–resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

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Rea

Ungania

et al. 2021

J Exp Clin Cancer Res

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Background 223Ra is currently used for treatment of metastatic castration resistant prostate cancer patients (mCRPC) bone metastases with fixed standard activity. Individualized treatments, based on adsorbed dose (AD) in target and non-target tissue, are absolutely needed to optimize efficacy while reducing toxicity of α-emitter targeted therapy. This is a pilot first in human clinical trial aimed to correlate dosimetry, clinical response and biological side effects to personalize 223Ra treatment. Methods Out of 20 mCRPC patients who underwent standard 223Ra treatment and dosimetry, in a subset of 5 patients the AD to target and non-target tissues was correlated with clinical effects and radiation-induced chromosome damages. Before each 223Ra administrations, haematological parameters, PSA and ALP values were evaluated. Additional blood samples were obtained baseline (T0), at 7 days (T7), 30 days (T30) and 180 days (T180) to evaluate chromosome damage. After administration WB planar 223Ra images were obtained at 2–4 and 18–24 h. Treatment response and toxicity were monitored with clinical evaluation, bone scan, 18F-choline-PET/CT, PSA value and ALP while haematological parameters were evaluated weekly after 223Ra injection and 2 months after last cycle. Results 1. a correlation between AD to target and clinical response was evidenced with threshold of 20 Gy as a cut-off to obtain tumor control; 2. the AD to red marrow was lower than 2 Gy in all the patients with no apparently correlation between dosimetry and clinical toxicity. 3. a high dose dependent increase of the number of dicentrics and micronuclei during the course of 223Ra therapy was observed and a linear correlation has been found between blood AD (BAD) and number of dicentrics. Conclusions This study provides some interesting preliminary evidence to be further investigated: dosimetry may be useful to identify a more appropriate 223Ra administered activity predicting AD to target tissue; a dose dependent complex chromosome damage occurs during 223Ra administration and this injury is more evident in heavily pre-treated patients; dosimetry could be used for radioprotection purpose. Trial registration The pilot study has been approved from the Ethics Committee of Regina Elena National Cancer Institute (N:RS1083/18–2111).

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Section: Methodsmentioning

confidence: 99%

The role of dosimetry and biological effects in metastatic castration–resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

Sciuto

Rea

Ungania

et al. 2021

J Exp Clin Cancer Res

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“…Therefore ionization chambers must be calibrated for each volume. Ionization chamber efficiency variation with radioactive solution volume has been experimentally observed [2,34,46,49,[51][52][53][54][55][56]. The ionization chamber efficiency variation is typically less sensitive to volume variation for radionuclides that emit high energy photons like 56 Co or 18 F [57] than for radionuclides that emit low energy photons like 111 In, 133 Ba or 125 I [53] or beta emitters [56,[58][59][60].…”

Section: Volume Variationmentioning

confidence: 99%

Uncertainty evaluation in activity measurements using ionization chambers

et al. 2015

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Pressurized re-entrant (or 4π) ionization chambers (ICs) connected to current-measuring electronics are used for activity measurements of photon emitting radionuclides and some beta emitters in the fields of metrology and nuclear medicine. As a secondary method, these instruments need to be calibrated with appropriate activity standards from primary or direct standardization. The use of these instruments over 50 years has been well described in numerous publications, such as the Monographie BIPM-4 and the special issue of Metrologia on radionuclide metrology (

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“…Unfortunately, manufacturers supply calibration coefficient for a specific number of sources, thus, the calculation of other sources' correction factors is indispensable to assure the accuracy of the DC response. This task can be performed using various methods such as Monte Carlo Method and some experimental methods that should be selected in accordance with the accuracy required for the assay [3,4,5]. The significance of these factors depends strongly on the radionuclide type: studies suggest that the beta emitters are more sensitive to the container material, as the self-absorption phenomenon is more important for this type of radiation [6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Development of a GUI for automating quality control of dose calibrators using Python

et al. 2021

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Quality control of dose calibrators is essential to evaluate the accuracy of the instrument response. In this work, a GUI (Graphical User Interface) has been developed to facilitate performing and recording quality control tests of dose calibrators. The interface is capable to automate several tests which include routine checks, accuracy test, linearity test, reproducibility test, repeatability test, concordance MBq/mCi test, and geometry test. In principle, the program computes correction factors that should be applied to minimize the uncertainty of measurements and the determining factors for success or failure of each test, then visualizes the results as tables and curves into a pdf file. Therefore, this interface can be considered as an efficient tool for performing quality control tests of dose calibrators thought it is still unable to offer the correction factors for the geometry test without experiment which will be achieved by integrating Monte Carlo simulation into the GUI.

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Comparison of methods to determine accurate dose calibrator activity measurements

Cited by 5 publications

References 2 publications

The role of dosimetry and biological effects in metastatic castration–resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

The role of dosimetry and biological effects in metastatic castration–resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

Uncertainty evaluation in activity measurements using ionization chambers

Development of a GUI for automating quality control of dose calibrators using Python

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