A simplified edge illumination set-up for quantitative phase contrast mammography with synchrotron radiation at clinical doses

This work presents the first study of x-ray phase contrast imaging based on a simple implementation of the edge illumination method (EIXPCi) in the field of mammography with synchrotron radiation. A simplified EIXPCi set-up was utilized to study a possible application in mammography at clinical doses. Moreover, through a novel algorithm capable of separating and quantifying absorption and phase perturbations of images acquired in EIXPCi modality, it is possible to extract quantitative information on breast images, allowing an accurate tissue identification. The study was carried out at the SYRMEP beamline of Elettra synchrotron radiation facility (Trieste, Italy), where a mastectomy specimen was investigated with the EIXPCi technique. The sample was exposed at three different energies suitable for mammography with synchrotron radiation in order to test the validity of the novel algorithm in extracting values of linear attenuation coefficients integrated over the sample thickness. It is demonstrated that the quantitative data are in good agreement with the theoretical values of linear attenuation coefficients calculated on the hypothesis of the breast with a given composition. The results are promising and encourage the current efforts to apply the method in mammography with synchrotron radiation

Non-vascular interventional procedures: effective dose to patient and equivalent dose to abdominal organs by means of dicom images and Monte Carlo simulation

This study evaluates X-ray exposure in patient undergoing abdominal extra-vascular interventional procedures by means of Digital Imaging and COmmunications in Medicine (DICOM) image headers and Monte Carlo simulation. The main aim was to assess the effective and equivalent doses, under the hypothesis of their correlation with the dose area product (DAP) measured during each examination. This allows to collect dosimetric information about each patient and to evaluate associated risks without resorting to in vivo dosimetry. The dose calculation was performed in 79 procedures through the Monte Carlo simulator PCXMC (A PC-based Monte Carlo program for calculating patient doses in medical X-ray examinations), by using the real geometrical and dosimetric irradiation conditions, automatically extracted from DICOM headers. The DAP measurements were also validated by using thermoluminescent dosimeters on an anthropomorphic phantom. The expected linear correlation between effective doses and DAP was confirmed with an R(2) of 0.974. Moreover, in order to easily calculate patient doses, conversion coefficients that relate equivalent doses to measurable quantities, such as DAP, were obtained

Validation of 99m^{99m} 99 m Tc and 177^{177} 177 Lu quantification parameters for a Monte Carlo modelled gamma camera

Abstract Purpose Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many physical phenomena which are difficult to track or measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, validating MC results with real data acquired with gamma camera is mandatory. The aim of this study was the validation of the calibration factor (CF) and the recovery coefficient (RC) obtained with SIMIND Monte Carlo code for modeling a Siemens Symbia Intevo Excel SPECT-CT gamma camera to ensure optimal $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu SPECT quantification. Methods Phantom experiments using $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu have been performed to measure spatial resolution and sensitivity, as well as to evaluate the CF and RC from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source while for 3D volumetric imaging were (3) a uniform filled cylinder phantom and (4) a Jaszczack phantom with spheres of different volumes. The experimental results have been compared with the results obtained from Monte Carlo simulations performed in the same geometries. Results Comparison shows good accordance between simulated and experimental data. The measured planar spatial resolution was 8.3 $$\pm 0.8$$ ± 0.8  mm for $$^{99m}$$ 99 m Tc and 11.8±0.6 mm for $$^{177}$$ 177 Lu. The corresponding data obtained by SIMIND for $$^{99m}$$ 99 m Tc was 7.8±0.1 mm, while for $$^{177}$$ 177 Lu was 12.4±0.4 mm. The CF was 110.1±5.5 cps/MBq for Technetium and 18.3±1.0 cps/MBq for Lutetium. The corresponding CF obtained by SIMIND for $$^{99m}$$ 99 m Tc was 107.3±0.3 cps/MBq, while for $$^{177}$$ 177 Lu 20.4±0.7 cps/MBq. Moreover, a complete curve RCs vs Volume (ml) both for Technetium and Lutetium was determined to correct the PVE for all volumes of clinical interest. In none of the cases, a RC coefficient equal to 100 was found. Conclusions The validation of quantification parameters shows that SIMIND can be used for simulating both gamma camera planar and SPECT images of Siemens Symbia Intevo using $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu radionuclides for different medical purposes and treatments

Variable tilt-angle, parallel-hole collimation system for high-resolution molecular imaging gamma tomosynthesis

Purpose: This study investigates a novel gamma tomosynthesis (GT) method based on a variable tilt-angle, parallel-hole collimator (VAPHC) which, mounting to a conventional gamma, is able to perform high-resolution three-dimensional imaging. Methods: The VAPHC has the remarkable feature to be modular, consisting of independent collimation elements able to tilt according to variable angles [−45° to +45°]. Spatial resolutions were measured in reconstructed GT images using a point source at different source-to-collimator distances, while sensitivity was evaluated over the range of slant angles using a disk-source. Image contrast (IC) and contrast-to-noise-ratio (CNR) of sub-centimeters tumors were evaluated using a breast phantom containing a background activity and spheres filled with 99mTc to simulate lesions at two depths. Breast phantom GT images were compared with planar and circularorbit SPECT acquisitions of equal scan-time. Results: Planar spatial resolutions range from 9 to 14mm over a depth range of 6–10 cm; spatial resolution in depth dimension becomes two times greater than those in the other dimensions. The measured sensitivity decreases from 9 cps/μCi to 6 cps/μCi varying the slant angle from 5° to 45°. The measured IC and CNR of GT reconstructed images demonstrated that it was possible to improve the spatial resolution/sensitivity trade-off. Conclusions: The proposed GT based VAPHC demonstrated the potential for superior spatial resolution and contrast compared to planar and SPECT acquisitions. A conventional gamma camera equipped with the VAPHC could be located at the minimum distance from the patient, thus improving detection, localisation and characterisation of sub-centimetre lesions

Usefulness of iodine-123 whole-body scan in planning iodine-131 treatment of the differentiated thyroid carcinoma in children and adolescence

OBJECTIVE: Radioiodine treatment (RAI-T) of differentiated thyroid carcinoma (DTC) is important to avoid disease progression, in particular in pediatric patients. For these reasons, a diagnostic scan may be useful to assess therapeutic tailored activity. The purpose of our study was to evaluate the usefulness of diagnostic whole-body scan (WBS) with iodine-123 (I) in combination with recombinant human thyroid-stimulating hormone (rh-TSH; Thyrogen) (rh-TSH-Dx-WBS), in planning RAI-T or further surgery before RAI-T in pediatric DTC. PATIENTS AND METHODS: Among 101 rh-TSH-Dx-WBS of 55 patients (21 males, mean age: 15 years, range: 5-18 years) followed at the Bambino Gesù Pediatric Hospital for DTC from February 2004 to December 2016, 41 rh-TSH-Dx-WBS scans of 41 patients (20 male and 21 female, mean age: 14 years, range: 5-18 years) performed for staging before RAI-T were retrospectively evaluated. Thyroglobulin was determined at baseline and on day 5. RESULTS: Receiver operating characteristic curve analysis showed that thyroglobulin alone is not a good predictor for staging modification (area under the curve=0.6855). rh-TSH-Dx-WBS showed both remnant and lymph node in 11 (27%), lymph node localization alone in one (2.5%), lung alone in 1/41 (2.5%), both lymph node and lungs in 2/41 (5%), and thyroid remnant alone in 26/41 (63%) patients. rh-TSH-Dx-WBS modified staging in 12/41 (29%): in 3/12 (25%) for the presence of lung metastases and in 9/12 (75%) for lymph node involvement. In all these patients, administered activity for RAI-T was then modified or further surgery was planned. CONCLUSION: Although further studies are needed, our data showed that combined use of rh-TSH and I-Dx-WBS allows an accurate and complete staging of disease, to implement the best therapeutic plan

Quantification of scatter radiation from radiographic procedures in a neonatal intensive care unit

Background In a neonatal intensive care unit (NICU), preterm infants are often exposed to a large number of radiographic examinations, which could cause adjacent neonates, family caregivers and staff members to be exposed to a dose amount due to scatter radiation. Objective To provide information on scatter radiation exposure levels in a NICU, to compare these values with the effective dose limits established by the European Union and to evaluate the effectiveness of radiation protection devices in this setting. Materials and methods Radiation exposure levels due to scatter radiation were estimated by passive detectors (thermoluminescent dosimeters) and direct dosimetric measurements (with a dose rate meter); in the latter case, an angular map of the scatter dose distribution was achieved. Results The dose due to scatter radiation to staff in our setting is approximately 160 μSv/year, which is markedly lower than the effective dose limit for workers established by the European Union (20 mSv/year). The doses range between 0.012 and 0.095 μSv/radiograph. Considering a mean hospitalization period of 3 months and our NICU workload, the corresponding scatter radiation dose to an adjacent patient and/or his/her caregiver is at most 40 μSv. Conclusion For distances greater than 1 m from the irradiation field, both scatter dose absorbed by a staff member during a year and that by an adjacent patient and/or his/her caregiver during hospitalization is less than 1 mSv, which is the exposure limit for public members in a year

The Italian young medical physicist scenario: Results from the young AIFM group survey

International audiencePurposeThe young working group of the Italian Association of Medical and Health Physics (AIFM) designed a survey to assess the current situation of the under 35 AIFM members.MethodsAn online survey including 65 questions was designed to gather personal information, educational issues, working and research experience, and to evaluate the AIFM activities. The survey was distributed to the under 35 members between November 2022 and February 2023, through the young AIFM mailing list and social media.Results160 answers from 230 affiliates (70%, 31 years median age) were obtained. The results highlighted that 87% of the respondents had a fixed term/permanent employment, mainly in public hospitals (58%).Regarding Medical Physicists (MPs) training, 54% of the students left their region of origin due to the training plan (40%) and the availability of scholarships (25%) in the chosen university. Most of the respondents have no Radiation Protection Expert title, while the remaining 20%, 6%, and 3% are qualified to the first, second, and third level, respectively.Several young MPs (62.2%) were involved in research activities; however, only 28% had teaching experience, mainly within their workplace (20%, safety courses), during AIFM courses (4%), or university lectures (3%).ConclusionsThis survey reported the current situation of the under 35 AIFM members, highlighting the “brain drain” phenomenon from the south to the north of Italy, mainly due to the lack of post-graduate schools, scholarships, and job opportunities. The obtained results will help the future working program of the AIFM