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Candela-Juan, C., Ballester, F., Perez-Calatayud, J., & Vijande, J. (2015). Assaying multiple I-125 seeds with the well-ionization chamber SourceCheck(4 Pi) 33005 and a new insert. J. Contemp. Brachytherapy, 7(6), 492–496.
Abstract: Purpose: To provide a practical solution that can be adopted in clinical routine to fulfill the AAPM-ESTRO recommendations regarding quality assurance of seeds used in prostate permanent brachytherapy. The aim is to design a new insert for the well-ionization chamber SourceCheck(4 Pi) 33005 (PTW, Germany) that allows evaluating the mean air-kerma strength of up to ten I-125 seeds with one single measurement instead of measuring each seed individually. Material and methods: The material required is: a) the SourceCheck(4 Pi) 33005 well-ionization chamber provided with a PTW insert to measure the air-kerma strength S-K of one single seed at a time; b) a newly designed insert that accommodates ten seeds in one column, which allows measuring the mean S-K of the ten seeds in one single measurement; and c) a container with ten seeds from the same batch and class of the seeds used for the patient implant, and a set of nine non-radioactive seeds.The new insert is characterized by determining its calibration coefficient, used to convert the reading of the well-chamber when ten seeds are measured to their mean S-K. The proposed method is validated by comparing the mean S-K of the ten seeds obtained from the new insert with the individual measurement of S-K of each seed, evaluated with the PTW insert. Results: The ratio between the calibration coefficient of the new insert and the calibration coefficient of the PTW insert for the SourceCheck(4 Pi) 33005 is 1.135 +/- 0.007 (k = 1). The mean S-K of a set of ten seeds evaluated with this new system is in agreement with the mean value obtained from measuring independently the S-K of each seed. Conclusions: The new insert and procedure allow evaluating the mean S-K of ten seeds prior to the implant in a single measurement. The method is faster and more efficient from radiation protection point of view than measuring the individual S-K of each seed.
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Oliver-Cañamas, L., Vijande, J., Candela-Juan, C., & Perez-Calatayud, J. (2025). Dosimetry audits in high dose rate brachytherapy: A survey on the current scenario in Europe. Phys. Medica, 136, 105047–7pp.
Abstract: Introduction: This work aims to study the current scenario of dosimetry audits in high dose rate (HDR) brachytherapy (BT) in Europe to evaluate whether there is a need to implement more services of this type and to define the characteristics that they should meet according to users. Material and methods: A survey consisting of 30 multiple choice questions was designed and distributed among European centers. The estimated time to answer was less than 15 min. 74 HDR BT centers participated, having 192Ir, 60Co and/or electronic sources. Information about users' opinions and experience with dosimetry audits in this field, center resources and quality assurance (QA) procedures was gathered. Results: For 61 % of users, dosimetry audits in HDR BT should be recommended, but not mandatory, whereas 35 % suggested that they are necessary and should be compulsory. Only for 4 % of participants these audits are not necessary. In contrast, 86 % of users found that the current number of these services is inadequate and that more national and/or international services are needed. Most participants operate according to QA recommendations of published guidelines, with exceptions, such as the use of the Reference Air Kerma Rate provided by the manufacturer instead of the one measured by the home medical physicist. Conclusion: The number of HDR BT dosimetry audits available to users is inadequate and there is a need to implement more national and/or international services of this type. Some technical aspects that an audit of this type should fulfill are outlined in this work.
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Orr, R. S. et al, Lacasta, C., Solaz, C., & Soldevila, U. (2026). Quality Assurance during production of the ATLAS18 ITk strip sensors. Nucl. Instrum. Methods Phys. Res. A, 1092, 171920–8pp.
Abstract: We describe the extensive quality assurance programme undertaken during the production of the ATLAS ITk strip sensors. Quality Assurance (QA) is the systematic process of preventing defects during production, rather than identifying them after the fact. QA is performed on test structures fabricated at the periphery of the same wafers used to produce the actual sensors, thus ensuring that these structures are a good representation of the sensor and process quality. The test structures consist of test chips, which include strips, diodes, MOS capacitors, and special structures for monitoring of parameters such as bias resistor values, interstrip resistance, coupling capacitance and flat band voltage. Additionally, miniature sensors with the same design as the main sensor, but with reduced area, allow measurement of the charge generated during irradiation with a beta source. Test structure semiconductor parameters are measured on both unirradiated samples and samples subjected to irradiation. The test chips are irradiated using gammas and reactor neutrons to the equivalent dose (660 kGy) and fluence (1.6 & times;1015 neq/cm2) expected in the high luminosity-LHC after 1.5 times its lifetime of 14 years. Miniature sensors are irradiated to the same neutron fluence as the test chips, or the equivalent proton fluence. Monitor diodes are irradiated alternatively to the maximum fluence to measure the degradation of the leakage current, and to one third this value to observe the full depletion voltage within the operational range of the measurement setups. Unirradiated test structures are measured on a probe station at room temperature. Irradiated test structures are wire-bonded to a PCB to provide connectivity, and measured at-21 degrees C and 4% relative humidity.
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Perez-Curbelo, J., Carvalho, C. M., Schafasand, M., Rossomme, S., Llosa, G., & Grevillot, L. (2026). Assessing the delivery error detection sensitivity of a new 2D detector prototype for carbon ion PSQA measurements. J. Appl. Clin. Med. Phys, 27(5), e70580–6pp.
Abstract: Background Particle therapy requires stringent patient-specific quality assurance (PSQA) to validate dose distributions delivered by the system. Purpose This study presents preliminary results on the performance evaluation of the MatriXX AiR 2D ionization-chamber array for patient-specific QA (PSQA) in carbon-ion therapy, comparing measured and planned dose distributions. Methods A series of 10 test cases, including a treatment plan for a box-shaped target (6-cm side length), uniformly covered by the dose and nine patient-specific treatment plans, were assessed. Measurements were conducted at two water equivalent depths using RW3 phantoms: beam entrance and within the Spread-Out Bragg Peak (SOBP). The study examined the detector's ability to detect deviations by systematically modifying treatment plans, comparing the measured and planned dose utilizing gamma index analysis. Results Passing rate analysis revealed depth-dependent sensitivity to treatment plan delivery modifications. Measurements at the entrance depth showed better sensitivity to delivery changes than those taken within the SOBP Conclusions The MatriXX AiR detector demonstrated strong potential for PSQA in carbon ion therapy. These findings support its application in clinical workflows to enhance treatment verification and accuracy.
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