Radiation dose reduction and static image quality assessment using a channelized hotelling observer on an angiography system upgraded with clarity IQ.

The goal of this paper was the comparison of radiation dose and imaging quality before and after the Clarity IQ technology installation in a Philips AlluraXper FD20/20 angiography system using a Channelized Hotelling Observer model (CHO). The core characteristics of the Allura Clarity IQ technology are its real-time noise reduction algorithms (NRT) combined with state-of-the-art hardware; this technology allows to implement acquisition protocols able to significantly reduce patient entrance dose. To measure the system performances in terms of image quality we used a contrast detail phantom in a clinical scatter condition. A Leeds TO10 phantom has been imaged between two 10 cm thick homogeneous solid water slabs. Fluoroscopy images were acquired using a cerebral protocol at 3 dose levels (low, medium and high) with a field- of view (FOV) of 31 cm. Cineangiography images were acquired using a cerebral protocol at 2 fps. Thus, 4 acquisitions were obtained for the conventional technology and 4 acquisitions were taken after the Clarity IQ upgrade, for a total of 8 different image sets. A validated 40 Gabor channels CHO with an internal noise model compared the image sets. Human observers' studies were carried out to tune the internal noise parameter. We showed that the CHO did not detect any significant difference between any of the image sets acquired using the two technologies. Consequently, this x-ray imaging technology provides a non-inferior image quality with an average patient dose reduction of 57% and 28% respectively in cineangiography and fluoroscopy. The Clarity IQ installation has certainly allowed a considerable improvement in patient and staff safety, while maintaining the same image quality.

Radiomic Profiling of Head and Neck Cancer: 18F-FDG PET Texture Analysis as Predictor of Patient Survival.

Background and Purpose: The accurate prediction of prognosis and pattern of failure is crucial for optimizing treatment strategies for patients with cancer, and early evidence suggests that image texture analysis has great potential in predicting outcome both in terms of local control and treatment toxicity. The aim of this study was to assess the value of pretreatment 18F-FDG PET texture analysis for the prediction of treatment failure in primary head and neck squamous cell carcinoma (HNSCC) treated with concurrent chemoradiation therapy. Methods: We performed a retrospective analysis of 90 patients diagnosed with primary HNSCC treated between January 2010 and June 2017 with concurrent chemo-radiotherapy. All patients underwent 18F-FDG PET/CT before treatment. 18F-FDG PET/CT texture features of the whole primary tumor were measured using an open-source texture analysis package. Least absolute shrinkage and selection operator (LASSO) was employed to select the features that are associated the most with clinical outcome, as progression-free survival and overall survival. We performed a univariate and multivariate analysis between all the relevant texture parameters and local failure, adjusting for age, sex, smoking, primary tumor site, and primary tumor stage. Harrell c-index was employed to score the predictive power of the multivariate cox regression models. Results: Twenty patients (22.2%) developed local failure, whereas the remaining 70 (77.8%) achieved durable local control. Multivariate analysis revealed that one feature, defined as low-intensity long-run emphasis (LILRE), was a significant predictor of outcome regardless of clinical variables (hazard ratio < 0.001, P=0.001).The multivariate model based on imaging biomarkers resulted superior in predicting local failure with a c-index of 0.76 against 0.65 of the model based on clinical variables alone. Conclusion: LILRE, evaluated on pretreatment 18F-FDG PET/CT, is associated with higher local failure in patients with HNSCC treated with chemoradiotherapy. Using texture analysis in addition to clinical variables may be useful in predicting local control.

Feasibility of voxel-based Dose Painting for recurrent Glioblastoma guided by ADC values of Diffusion-Weighted MR imaging.

PURPOSE: Glioblastoma Multiforme (GBM) is the most common malignant brain tumor and frequently recurs in the same location after radiotherapy. Intensive treatment targeting localized lesion is required to improve GBM outcome, but dose escalation using conventional methods is limited by healthy tissue tolerance. Helical Tomotherapy (HT) Dose Painting (DP) treatments were simulated to safely deliver high doses in the recurrent regions. MATERIALS AND METHODS: Apparent Diffusion Coefficient (ADC) data from five recurrent GBM were retrospectively considered for planning. Hypo-fractionated (25-50Gy, 5 fractions) voxel-based prescriptions were opportunely converted to personalized structured-based dose maps to create DP plans with a commercial Treatment Planning System. Optimized plans were generated and analyzed in terms of plan conformity to dose prescription (Q0.90-1.10), tolerance of the healthy tissues (DMAX), and dosimetry accuracy of the deliverable plans (γ-index). RESULTS: Only three of the five cases could receive a safe retreatment without violating the maximum critical organs dose constraints. The conformity of the simulated plans was between 40.9% and 79.9% (Q0.90-1.10), their delivery time was in the range of 38.3-63.6min, while the dosimetry showed γ-index of 82.4-92.4%. CONCLUSIONS: This study proved the ability of our method to simulate personalized, deliverable and dosimetrically accurate DPBN plans. HT hypo-fractionated treatments guided by ADC maps can be realized and applied to deliver high doses in the GBM recurrent regions, although there are some critical issues related to low Q0.90-1.10 values, to exceeding of healthy-tissue dose constraints for some patients and long delivery times.

Quantitative comparison between the commercial software STRATOS(®) by Philips and a homemade software for voxel-dosimetry in radiopeptide therapy.

BACKGROUND: Targeted radionuclide therapy is a rapidly growing modality. A few commercial treatment planning systems are entering the market. However, some in-house systems are currently developed for a more flexible and customized dosimetry calculation at voxel-level. For this purpose, we developed a novel software, VoxelMed, and performed a comparison with the software STRATOS. METHODS: The validation of both of them was undertaken using radioactive phantoms with different volume inserts. A cohort of 10 patients was also studied after a therapeutic administration of (177)Lu-labelled radiopeptides. The activity, number of disintegrations, absorbed dose and dose-volume histogram (DVH) were calculated for the phantoms and the kidneys in patients, which were the main critical organs at risk in this study. RESULTS: In phantoms the absorbed doses computed with VoxelMed and STRATOS agree within 5%. In patients at the voxel-level the absorbed dose to kidneys (VoxelMed: mean 0.66 Gy/GBq) showed a limited difference of 5%, but with a remarkable range (-40%, +60%) between the two software packages. Voxel-dosimetry allows to estimate the dose non-homogeneities in volumes, which may be evaluated through DVHs. CONCLUSION: This study demonstrates that a fully 3D voxel-dosimetry with multiple SPECT images is feasible by using home-made or commercial software package and absorbed dose results obtained are similar. The main difference between the studied tools was observed in the activity integration method (effective vs physical half-time to time activity curve tail). We believe that an effective half-time integration method produces a more accurate approximation of clinical uptake and resultant dosimetry.

Kidney dosimetry in ¹77Lu and 9°Y peptide receptor radionuclide therapy: influence of image timing, time-activity integration method, and risk factors.

Kidney dosimetry in (177)Lu and (90)Y PRRT requires 3 to 6 whole-body/SPECT scans to extrapolate the peptide kinetics, and it is considered time and resource consuming. We investigated the most adequate timing for imaging and time-activity interpolating curve, as well as the performance of a simplified dosimetry, by means of just 1-2 scans. Finally the influence of risk factors and of the peptide (DOTATOC versus DOTATATE) is considered. 28 patients treated at first cycle with (177)Lu DOTATATE and 30 with (177)Lu DOTATOC underwent SPECT scans at 2 and 6 hours, 1, 2, and 3 days after the radiopharmaceutical injection. Dose was calculated with our simplified method, as well as the ones most used in the clinic, that is, trapezoids, monoexponential, and biexponential functions. The same was done skipping the 6 h and the 3 d points. We found that data should be collected until 100 h for (177)Lu therapy and 70 h for (90)Y therapy, otherwise the dose calculation is strongly influenced by the curve interpolating the data and should be carefully chosen. Risk factors (hypertension, diabetes) cause a rather statistically significant 20% increase in dose (t-test, P < 0.10), with DOTATATE affecting an increase of 25% compared to DOTATOC (t-test, P < 0.05).

Size assessment of breast lesions by means of a computer-aided detection (CAD) system for magnetic resonance mammography.

PURPOSE: The aim of this study was to investigate the efficacy of a dedicated software tool for automated volume measurement of breast lesions in contrast-enhanced (CE) magnetic resonance mammography (MRM). MATERIAL AND METHODS: The size of 52 breast lesions with a known histopathological diagnosis (three benign, 49 malignant) was automatically evaluated using different techniques. The volume of all lesions was measured automatically (AVM) from CE 3D MRM examinations by means of a computer-aided detection (CAD) system and compared with the size estimates based on maximum diameter measurement (MDM) on MRM, ultrasonography (US), mammography and histopathology. RESULTS: Compared with histopathology as the reference method, AVM understimated lesion size by 4% on average. This result was similar to MDM (3% understimation, not significantly different) but significantly better than US and mammographic lesion measurements (24% and 33% size underestimation, respectively). CONCLUSIONS: AVM is as accurate as MDM but faster. Both methods are more accurate for size assessment of breast lesions compared with US and mammography.

PET/CT and radiotherapy : data transfer, radiotherapy workflow and quality assurance.

The development of new technologies in radiation therapy has made it possible to introduce more sophisticated techniques that can deliver the prescribed dose with more conformation and accuracy and to apply dose escalation protocols without increasing the risk of healthy tissue damage. This has consented the simultaneous delivery of different dose levels to different parts of the target, making it possible to boost those tumour sub-volumes that are considered more radio resistant. The use of PET for radiotherapy planning purposes has become increasingly important in the last few years, because of its ability to provide valuable biologic and functional data. PET imaging can affect the treatment strategy definition and improve the target delineation and the assessment of therapy response. The most attractive aspect is the perspective to deliver differential doses inside target volumes for areas of different biologic behaviour based on functional imaging, moving closer to the goals of biologically conformal radiation therapy. Each single step of PET/CT-guided radiotherapy workflow, needs to be performed following high standard procedures, within a rigorous and appropriate quality assurance protocol to minimize the sources of errors and to maximize the efficacy of PET imaging in radiation therapy, ensuring safe and effective use of the technology. The present paper focuses on aspects concerning the use of PET/CT in radiation treatment process, with the aim to delineate different possible approaches to its clinical application and to highlight the critical aspects of the various subprocesses.

Dosimetric evaluation of a commercial 3-D treatment planning system using Report 55 by AAPM Task Group 23.

BACKGROUND AND PURPOSE: A relevant part of radiotherapy treatment planning system QA concerns dose calculation verification. Report 55 by AAPM TG-23 is an instrument for performing dosimetric evaluation of treatment planning systems in case of external photon beams. It was employed by different groups in three radiotherapy departments for controlling performances of RTPS CadPlan Varian-Dosetek, versions 2.7.9, 3.0.6 and 3.1.1. MATERIALS AND METHODS: Once the basic data of the AAPM 4 MV and 18 MV X-ray units had been converted into the CadPlan format and the AAPM units configured, the whole set of TG23 tests were carried out on three different systems. According to Report 55, comparisons between values measured by TG-23 and calculated by RTPS were made in terms of dose at selected points and radiological field width at different depths. RESULTS: As far as dose is concerned, 266 data were compared for 4 MV and 297 for 18 MV. Ninety-five-point-nine percent of dose deviations for 4 MV and 92.6% for 18 MV are less than 2%. Most of the relevant discrepancies for both energies occur in a test case where dose has to be calculated under a long narrow block centred on the beam axis. Deviations as much as 6.1% for 4 MV and -7.5% for 18 MV were observed in points at 1 cm depth under the block. Poor results were also observed in the rectangular field 25 x 5, in points outside the field edges under collimators. As regards radiological field width, 58 out of 64 comparisons for 4 MV occurred in the range +/- 2 mm. For 18 MV the biggest deviation was -2.2 mm. CONCLUSIONS: The TG-23 tests demonstrated that the accuracy of the RTPS in dose calculation is good in most of the typical radiotherapy applications. Our results are better than those recently published for other RTPS. The TG-23 package turned out to be an effective instrument for QA and calculation verification, as well as being a powerful method for training purpose in configuring and using a RTPS.

[Radical nephrectomy in renal carcinoma: surprising and unusual clinical and diagnostic features and prognostic factors in 20 consecutive cases]. / Nefrectomia radicale nel carcinoma renale: sorprendenti ed inconsueti aspetti clinici e diagnostici e fattori prognostici in 20 casi consecutivi.

The Authors reports the recent experience on renal carcinoma. The clinical beginning and the diagnostic consequences are emphasized.

[Bone metastasis of hepatocarcinoma. Review of the literature, radiologic pictures and personal caseload]. / Metastasi ossee di epatocarcinomi. Revisione della letteratura, quadri radiologici e casistica personale.

Prognosis of patients affected with hepatocellular carcinoma (HCC) has been improved by the modern imaging techniques allowing an early diagnosis and by the value of the therapeutic protocols employed. Staging has also become more and more important. Bone metastases from HCC are reportedly rare. The authors observed a 5.5% incidence in 90 cases of hepatocarcinoma. The metastases were demonstrated by radiography, CT, and nuclear scintigraphy, in patients with skeletal pain. The plain film appearance of skeletal metastases from HCC was osteolytic in all cases; no surrounding sclerosis was seen. CT scans demonstrated the destructive nature of these lesions, which were associated with bulky soft-tissue masses. Metastases exhibited increased radiotracer (99mTc-MDP) uptake at bone scintigraphy. The authors believe that bone scintigraphy should be included in the staging protocols of the HCCs which need a potentially curative therapy.

[Ultrasound-guided percutaneous needle biopsy in hepatic lesions suspected of hepatocarcinoma. Evaluation of 104 patients]. / Agobiopsia percutanea ecoguidata di lesioni epatiche sospette per epatocarcinoma. Valutazione su 104 pazienti.

The use of US in both everyday routine and regular follow-up of patients affected with chronic hepatopathies makes it possible to detect even very small focal liver lesions. However, in many cases, neither US nor any other imaging method is sufficient for tissue characterization, and biopsy becomes thus indispensable to establish the diagnosis of hepatocellular carcinoma (HCC). The authors report the results of the US-guided biopsies with fine aspirating and cutting needles (FNAB) performed in 104 patients affected with focal liver lesions suspected for HCC. Smear cytology detected 67/83 proven HCCs: in 4 patients it showed a kind of malignancy which could not be typified; the patterns suggestive of HCC were 2, the false negatives were 7 and the inadequates 3. Microhistology, which was performed in 81 patients, allowed HCC to be diagnosed in 56 cases; a diagnosis of generic malignancy was made in 2 patients. There were 9 true negatives, 6 false negative, and 8 inadequates. Thanks to the combination of the two methods, 77 HCCs were diagnosed, with 92.8% typyfying accuracy; the false negatives were 4 and the inadequates 2. Typifying accuracy reached 95.8% in the group of 72 patients, all affected with HCC, in which both investigations were performed; there were 2 false negatives and 1 inadequate. These results confirm the value of US-guided FNAB in the diagnosis of HCC and the complementary role of smear cytology and microhistology: the combined use of the latter methods allows both false-negative and inadequate findings to be markedly reduced.

[Role of echography in the diagnosis and treatment monitoring of congenital acetabular dysplasia. Personal experience with 2000 examined children]. / Ruolo dell'ecografia nella diagnosi e nel monitoraggio della terapia delle displasie acetabolari congenite. Esperienza personale su 2000 bambini esaminati.

Since 1987 the authors have used sonography (US) as the means to detect dysplasia and congenital dislocation of infant hips, to define severity of the disease, and to monitor the results during treatment. In this paper the authors report their experience in 2000 examined babies. In 20 young patients, mainly females, 25 pathologic joints were detected and classified as 2c-4 hips. Orthopedic treatment employed Pavlick harness and, in case of partial success, Milgram abduction pillow too. This treatment has always been successful, except for a case with severe dislocation with echostructural changes in the acetabular cartilage. In this case, surgery was necessary. "Delayed ossification" (type 2b hips) and physiological immatury (type 2a hips) with alpha angle greater than or equal to 55 degrees were not splinted in abduction: normal maturity has always been attained without dysplastic involutions. Our experience confirmed US value in the early diagnosis of congenital acetabular dysplasia, when clinics exhibited evident limitations. Nonetheless, management and economical problems are still to be solved, due to the relationship of the widespread use of US in infant population and to its successful results, also considering the low incidence of the examined pathologic condition.