Purpose: To implement a semi-automatic planning technique for whole breast irradiation with two tangential IMRT fields and to test the produced dose distribution against clinical 3DCRT plans, for introducing the technique in clinical practice. Methods: The Auto-Planning module of the Pinnacle(3) (Philips) treatment planning system was used for generating a Treatment Technique on left-sided breast cancer patients treated in free breathing or in deep inspiration breath hold (DIBH) and to right-sided breast cancer patients. The technique was evaluated against 3DCRT clinical plans in terms of dosimetric plan parameters. Plan robustness toward patient displacements was assessed on a subset of patients by inducing shifts to the isocenter. Results: A statistically significant improvement in target coverage and dose homogeneity was observed for autoIMRT. No statistically significant differences were observed for ipsilateral organs, except for the ipsilateral lung in left DIBH, where slightly lower Dmean and V18% are registered for autoIMRT. Slightly higher Dmean doses (although far below the constraints) to contralateral organs were observed for autoIMRT plans. AutoIMRT plans were shown to be as robust as 3DCRT plans toward isocenter shifts, with a maximum decrease in CTV coverage of-2.2% and-2.1% for autoIMRT and 3DCRT, respectively. Average planning times were 40 min for 3DCRT and 6 min for IMRT plans. Conclusions: The developed autoIMRT technique was proven to be advantageous for target coverage and homogeneity and sufficiently robust towards isocenter displacements. The use of automated planning consistently reduces the planning workload with improvements in plan quality.

Published treatment technique comparisons for postoperative left-sided whole breast irradiation (WBI) with deep-inspiration breath-hold (DIBH) are scarce, small, and inconclusive. In this study, fully automated multi-criterial plan optimization, generating a single high-quality, Pareto-optimal plan per patient and treatment technique, was used to compare for a large patient cohort 1) intensity modulated radiotherapy (IMRT) with two tangential fields and 2) volumetric modulated arc therapy (VMAT) with two small tangential subarcs. Forty-eight randomly selected patients recently treated with DIBH and 16 × 2.66 Gy were included. The optimizer was configured for the clinical planning protocol. Comparisons between IMRT and VMAT included dosimetric plan parameters, estimated excess relative risks (ERR) for toxicities, delivery times, MUs, and deliverability accuracy at a linac. The automatically generated IMRT and VMAT plans applied in this study were similar or higher in quality than the manually generated clinical plans. For equal PTVin V95% (98.4 ± 0.9%), VMAT had significant advantages compared to IMRT regarding breast dose homogeneity and doses in heart and ipsilateral lung, at the cost of some minor deteriorations for contralateral breast (few cases with larger deteriorations) and lung. Conformality improved from 1.38 to 1.18 (p < 0.001). With VMAT, ERR for major coronary events and ipsilateral lung tumors were reduced by 3% (range: −1–12%) and 16% (range: −3–38%), respectively. MUs and delivery times were higher for VMAT. There were no statistical differences in γ passing rates. For WBI in conservative therapy of left-sided breast patients treated with DIBH, VMAT with two tangential subarcs was generally dosimetrically superior to IMRT with two tangential static fields. Results need confirmation by robustness analyses.

Radioprotection of the eye lens of medical staff involved in Surgical procedures is a subject of international debates since ICRP recommended, on 2011, a lower equivalent dose limit for the lens of the eye. In this work we address the effectiveness of different models of X-ray protective eyewear by relating actual dosimetry measurements to an ad hoc developed mathematical model, in order to disentangle the contribution of geometrical factors and shield capabilities. Phantom irradiation was carried out in fixed exposure conditions in angiographic room: we found that measured Dose Reduction Factors (DRF) strongly depend on the ergonomics of the investigated eyewear. Actually a very poor DRF was observed in the case of a glass model in spite of its high nominal attenuation, whereas a protective tool with low shielding capabilities such a visor resulted much more effective as a consequence of is shape (i.e. extended geometric protection of the eye lens). Our work highlights the need of the introduction of a specific parameter to quantify the effectiveness of the protection tools and able to predict their DRF by taking into account the geometry of the clinical condition of exposure. Aiming at making steps forward the standardization of the guidelines concerning the features of eye protective tools, we developed a simple mathematical model describing the eye lens irradiation geometry which allows the introduction, for each eyewear, of a comprehensive parameter, the Eye Protection Effectiveness (EPE), that, for any defined clinical irradiation condition and glass shielding capabilities and shape, defines the overall effective X-ray protection of the eyewear.

•RP 162 report establishes new suspension levels for fluorographic acquisition.•The application of RP 162 can help to obtain radiological equipment update.•New image processing algorithms can lead to an important patient dose reduction in interventional procedures.

Purpose To account for respiratory motion in radiotherapy treatment of lung lesions, 4DCT is often employed. For a correct reconstruction of respiratory phases, periodic and regular breathing is the underlying hypothesis when phase-binning algorithms are used. Aim of this work was to study the respiratory signals acquired during 4DCT and to evaluate whether a correlation exists between deviations from regularity of breathing signal and quality of reconstructed images. Methods and materials 4DCT of 40 patients acquired with a Philips Brilliance Big Bore CT were analyzed in this study. Respiratory signals were exported and an in-house written Matlab routine was used for extracting and processing the waveforms. The duration of each respiratory cycle (CD) was calculated as the distance between two consecutive maxima, while the fraction of inspiration (ID) was calculated as the ratio between the distance minimum–maximum and the duration of the whole cycle. Mean value (M), standard deviation ( σ ) and relative percentage error Er = σ M × 100 were extracted for each patient, the latter being a measurement of breathing regularity. Thereafter, 4DCT image quality was blindly scored from 1 to 4 (1: presence of visible artifacts in the reconstructed phases, 4: absence of visible artifacts). Patients were classified according to the score and mean relative percentage errors and standard deviations were calculated within each scoring class. Results In Fig. 1 mean relative percentage errors versus assigned score are reported for both CD and ID. A correlation between Er and image quality is clearly visible. Threshold values for Er of about 18% for CD and about 15% for ID can be identified as limits between good and bad quality reconstructed images. Conclusion To account for respiratory motion in radiotherapy treatment of lung lesions, 4DCT is often employed. For a correct reconstruction of respiratory phases, periodic and regular breathing is the underlying hypothesis when phase-binning algorithms are used. Aim of this work was to study the respiratory signals acquired during 4DCT and to evaluate whether a correlation exists between deviations from regularity of breathing signal and quality of reconstructed images. 4DCT of 40 patients acquired with a Philips Brilliance Big Bore CT were analyzed in this study. Respiratory signals were exported and an in-house written Matlab routine was used for extracting and processing the waveforms. The duration of each respiratory cycle (CD) was calculated as the distance between two consecutive maxima, while the fraction of inspiration (ID) was calculated as the ratio between the distance minimum–maximum and the duration of the whole cycle. Mean value (M), standard deviation ( σ ) and relative percentage error Er = σ M × 100 were extracted for each patient, the latter being a measurement of breathing regularity. Thereafter, 4DCT image quality was blindly scored from 1 to 4 (1: presence of visible artifacts in the reconstructed phases, 4: absence of visible artifacts). Patients were classified according to the score and mean relative percentage errors and standard deviations were calculated within each scoring class. In Fig. 1 mean relative percentage errors versus assigned score are reported for both CD and ID. A correlation between Er and image quality is clearly visible. Threshold values for Er of about 18% for CD and about 15% for ID can be identified as limits between good and bad quality reconstructed images.

Purpose Our Allura Xper FD20 system was installed in 2013 and mainly used for stroke treatment. To reduce the radiation dose delivered to patients though maintaining the required image quality, the system was recently upgraded to Allura Clarity. The core characteristics of Allura Clarity family are new real-time image processing algorithms to reduce image noise. The aim of this work is to show the advantages obtained in terms of dose reduction for cardiac, vascular and electrophysiological studies following such upgrade. Methods For both angiographic systems, the patient dose was assessed by means of K a,e (Entrance Air Kerma) measurements, using a PMMA phantom to simulate patient attenuation. The measurement set up was the referred method indicated in the RP162 report [ [1] European Commission. Criteria for Acceptability of Medical Radiological Equipmemt used in Diagnostic Radiology, Nuclear Medicine and Radiotheraphy. Radiation Protection n°162; 2012. Google Scholar ] and extensively described by Martin [ [2] Martin C.J. Protocol for measurement of surface dose rates for fluoroscopic X-ray equipment. Brit J Radiol. 1998; 71: 1283-1287 Google Scholar ]. For each investigated procedure, the measurements were carried out for most selectable fields of view and different PMMA thicknesses. The image quality was evaluated using Leeds TOR 18FG and FluoroMesh phantom for low contrast resolution and spatial resolution respectively. Results Depending on the procedure, the dose reduction is meaningful and ranges from 20% up to a factor of around 4 for fluorographic acquisitions. All K a,e values measured on Allura Clarity system are compliant with the Suspension Levels set out in the RP162 report [ [1] European Commission. Criteria for Acceptability of Medical Radiological Equipmemt used in Diagnostic Radiology, Nuclear Medicine and Radiotheraphy. Radiation Protection n°162; 2012. Google Scholar ] also for digital fluorographic acquisition mode. The image quality obtained with Allura Clarity is equivalent to that of the previous system. Conclusions The Allura Clarity delivers much lower dose to the patient for all clinical applications while maintaining an equivalent image quality. Our Allura Xper FD20 system was installed in 2013 and mainly used for stroke treatment. To reduce the radiation dose delivered to patients though maintaining the required image quality, the system was recently upgraded to Allura Clarity. The core characteristics of Allura Clarity family are new real-time image processing algorithms to reduce image noise. The aim of this work is to show the advantages obtained in terms of dose reduction for cardiac, vascular and electrophysiological studies following such upgrade. For both angiographic systems, the patient dose was assessed by means of K a,e (Entrance Air Kerma) measurements, using a PMMA phantom to simulate patient attenuation. The measurement set up was the referred method indicated in the RP162 report [ [1] European Commission. Criteria for Acceptability of Medical Radiological Equipmemt used in Diagnostic Radiology, Nuclear Medicine and Radiotheraphy. Radiation Protection n°162; 2012. Google Scholar ] and extensively described by Martin [ [2] Martin C.J. Protocol for measurement of surface dose rates for fluoroscopic X-ray equipment. Brit J Radiol. 1998; 71: 1283-1287 Google Scholar ]. For each investigated procedure, the measurements were carried out for most selectable fields of view and different PMMA thicknesses. The image quality was evaluated using Leeds TOR 18FG and FluoroMesh phantom for low contrast resolution and spatial resolution respectively. Depending on the procedure, the dose reduction is meaningful and ranges from 20% up to a factor of around 4 for fluorographic acquisitions. All K a,e values measured on Allura Clarity system are compliant with the Suspension Levels set out in the RP162 report [ [1] European Commission. Criteria for Acceptability of Medical Radiological Equipmemt used in Diagnostic Radiology, Nuclear Medicine and Radiotheraphy. Radiation Protection n°162; 2012. Google Scholar ] also for digital fluorographic acquisition mode. The image quality obtained with Allura Clarity is equivalent to that of the previous system. The Allura Clarity delivers much lower dose to the patient for all clinical applications while maintaining an equivalent image quality.

Purpose In head and neck (H&N) radiotherapy, an essential requirement is the reproducibility of the relative position of head and neck during the whole treatment. Moreover, adaptive radiotherapy for H&N cancer would benefit from indicators capable of easily identifying morphological alterations. Aim of this study was to test whether the immobilization device guarantees a reproducible head and neck position and to identify, on set-up verification images, some indicators capable of describing morphological alterations. Methods and materials A retrospective analysis on 15 patients immobilized using s-shaped head-neck-shoulders masks and treated with TomoTherapy (50–70 Gy/25-33fr) was conducted. For each treatment session two MVCT-CT registrations were performed alternatively optimizing matching on the head or the neck. For each patient mean differences between the two registrations parameters ( Δ x, Δ y, Δ z, Δ pitch, Δ roll, Δ yaw) over all treatment sessions were evaluated. Morphological alterations were studied (once a week for the whole treatment duration) by measuring on MVCT images the skin-to-skin distance at 3 different antero-posterior levels: at the center of parotid glands (line1) and 2 cm (line 2) and 4 cm (line 3) anteriorly. Mean percentage variations respect to the first week were evaluated for all patients. A Student’s t-test was carried out (p < 0,01). Results Mean differences between head and neck registration parameters are reported in Table 1. Except for two patients, mean differences were smaller than 1.7 mm and 1.2°. Mean percentage variations of lines’ length are reported in Fig. 1. For all, a decreasing trend was observed. Variations are statistically significant starting from the 4 th week for lines 1 and 2, and only from the 6 th week for line 3. Conclusion The immobilization device enables adequate H&N set-up during the whole treatment for almost all patients. Lines 1 and 2 drawn on MVCT images seem to be suitable for describing morphological alterations that might deserve re-planning.