Planar Scans Research Articles

Clinical impact of targeted single-photon emission computed tomography/computed tomography (SPECT/CT) bone scintigraphy on the assessment of bone metastasis in cancer patients.

We investigated the clinical impact of single-photon emission computed tomography/computed tomography (SPECT/CT) bone scintigraphy combined with 16-slice CT on metastatic workup and treatment planning in a large cancer patient series. Between January 2019 and January 2020, a total of 600 cancer patients were prospectively evaluated with whole-body planar bone scan (wbPBS) for staging or restaging purposes. 272/600 had equivocal lesions on wbPBS and 265/272 underwent additionally a targeted SPECT/CT bone scintigraphy on designated regions. Findings were classified as benign (score 1), metastatic (score 2) and inconclusive (score 3). Findings from SPECT/CT bone scintigraphy were compared with the results of wbPBS. A total of 668 lesions were considered as unclear οn wbPBS and were re-evaluated through targeted SPECT/CT bone scintigraphy. Definite diagnostic findings on SPECT/CT bone scintigraphy were obtained in 227/265 (85.7%) patients and in 592/668 (88.6%) lesions vs. 15.4% of wbPBS alone. On per-patient analyses, 38.9% of patients were considered definitely nonmetastatic and 46.8% as definitely metastatic. On per lesion analyses using SPECT/CT bone scintigraphy, corresponding diagnostic rates were 47.5 and 41.2%. Although the addition of SPECT/CT bone scintigraphy significantly reduced the rate of equivocal wbPBS results (83.1%), it failed to provide a conclusive diagnosis in a relatively small proportion of lesions 76/668 (11.4%) in 38 patients. SPECT/CT bone scintigraphy afforded a significant reduction of the number of patients with equivocal findings who needed further evaluation with other imaging modalities, preventing unnecessary delays in diagnosis and potential changes in disease staging and treatment planning. Moreover, SPECT/CT bone scintigraphy slightly increased diagnostic sensitivity.

A Comparison of the Distortion in the Same Field MRI and MR-Linac System With a 3D Printed Phantom.

PurposeA 3D printed geometric phantom was developed that can be scanned with computed tomography (CT) and magnetic resonance imaging (MRI) to measure the geometric distortion and determine the relevant dose changes.Materials and MethodsA self-designed 3D printed photosensitive resin phantom was used, which adopts grid-like structures and has 822 1 cm2 squares. The scanning plan was delivered by three MRI scanners: the Elekta Unity MR-Linac 1.5T, GE Signa HDe 1.5T, and GE Discovery-sim 750 3.0T. The geometric distortion comparison was concentrated on two 1.5T MRI systems, whereas the 3.0T MRI was used as a supplemental experiment. The most central transverse images in each dataset were selected to demonstrate the plane distortion. Some mark points were selected to analyze the distortion in the 3D direction based on the plane geometric distortion. A treatment plan was created with the off-line Monaco system.ResultsThe distortion increases gradually from the center to the outside. The distortion range is 0.79 ± 0.40 mm for the Unity, 1.31 ± 0.56 mm for the GE Signa HDe, and 2.82 ± 1.48 mm for the GE Discovery-sim 750. Additionally, the geometric distortion slightly affects the actual planning dose of the radiotherapy.ConclusionGeometric distortion increases gradually from the center to the outside. The distortion values of the Unity were smaller than those of the GE Signa HDe, and the Unity has the smallest geometric distortion. Finally, the Unity’s dose variation best matched with the standard treatment plan.

Added Value of SPECT/CT in Characterization of Extra-Skeletal Uptake of Tc-99m MDP on Planar Bone Scintigraphy in Known Cancer Patients.

Introduction: Extra-skeletal Tc-99m MDP uptake is not uncommon. It could be a problematic when it mimics a metastatic osseous lesion. Due to lack of proper anatomical localization, Planar bone scintigraphy (PBS) alone can't resolve this problem. Adding single photon emission tomography / computed tomography (SPECT/CT) images increases the diagnostic accuracy of planar bone scintigraphy. SPECT/CT has great impact on patients' management by preventing misinterpretation through precise localization and proper characterization of these uncertain lesions. In this study, we compared the diagnostic accuracy of SPECT/CT versus PBS in characterization of extra-skeletal lesions detected on conventional PBS in known cancer patients. Materials and Methods: This is a retrospective study including 50patients with known cancer referred for conventional (PBS) for metastatic work up. PBS was acquired followed by SPECT/CT images for the concerned area. Diagnostic performance indices from both modalities (PBS& SPECT/CT) were compared against the reference standard (clinical/imaging follow-up). Results: A total of 50 known cancer patients were included in this study (37 females, 13 males) with median age 64 years (range: 15-79). The sensitivity, specificity, and accuracy for SPECT/CT in identification of extra-osseous lesions all were 100% compared to 28%, 72% and 44% respectively for PBS. Uncertain lesions decreased from 38% to 0% by adding SPECT/CT.Only 10% of lesions showed calcium deposition, while the rest had other causes for extra-skeletal uptake. Conclusion: SPECT/CT enhances the diagnostic accuracy of planar bone scan for characterizations of extra-skeletal lesions that mimic osseous metastasis thus significantly impact patient’s management.

Added diagnostic value of SPECT to evaluate bone metastases inbreast cancer patients with normal whole body bone scan.

Background:In this research, we aimed to survey the added value of single photon emission computed tomography (SPECT) in comparison with planar whole body bone scan to visualize bone metastatic lesions in patients with breast cancer.Methods:A total of 80 patients with breast cancer (invasive ductal carcinoma) were examined with planar whole body bone scan and SPECT imaging using 99mTc-labelled methylene diphosphonate (99mTc-MDP). The patients with abnormal uptakes in SPECT imaging were also investigated with magnetic resonance imaging (MRI).Results:Among these 80 patients with normal whole body bone SPECT scan, 19 (23.25%) of them revealed abnormal 99mTc-MDP uptake in skeleton. Furthermore, these 19 patients were subjected to MRI and 3 (3.75%) of them were confirmed with metastatic bone lesion.Conclusion:The obtained data suggest that SPECT possess the added diagnostic over planar whole body bone scan.

Creation of a Three-Dimensional Printed Model for the Preoperative Planning of Hip Arthroscopy for Femoral Acetabular Impingement

We describe a technique that creates a 3-dimensional (3D) printed model from a patient’s own computed tomography scan. This introduces an adjunct to conventional imaging for the surgical management of femoral acetabular impingement. The creation of a tactile 1:1 scale model with patient-specific anatomy allows for free manipulation and inspection. This is compared to planar imaging and 3D-reconstructed computer tomography scans, which are limited in their degrees of movement. With a minimal learning curve because of a highly iterative process, no prior experience in 3D printing is required to successfully complete this technique. The primary barrier of entry is the initial start-up cost of a 3D printer; however, the price per print is minimal. These models are valuable clinical tools that can be used in preoperative planning, patient education, and medical trainee learning.

Comparison of the accuracy of optical impression systems in three different clinical situations.

To investigate the differences in accuracy (trueness and precision) of five different optical impression systems. The accuracy of the following optical impression systems was tested: (1) CEREC Bluecam (BL; Dentsply Sirona), (2) CEREC Omnicam (OM, Dentsply Sirona); (3) PlanScan (PL; Planmeca); (4) True Definition Scanner (TD; 3M ESPE); and (5) Trios 3 (TR; 3Shape). A standard plastic study model represented a patient with a fully dentate maxilla (ANA-4 V CER, frasaco). Three clinical situations were simulated: Patient 1 (P1): fully dentate; Patient 2 (P2): anterior partial edentulism (two missing incisors); and Patient 3 (P3): posterior partial edentulism (P3) (missing premolar and molar). The models were scanned with a reference scanner (IScan D104i, Imetric), and the digitalized models were used as reference for all comparisons. Then, optical impressions were made for the three clinical scenarios (n = 10 per group). In situation P1, the TD group provided the highest trueness (180.2 ± 46.3μm). In situation P2, the highest trueness was found in the TD (97.9 ± 27.6 μm) and TR (105 ± 9.5μm) groups, and in situation P3, TR had the highest trueness (P < .05) with a median RMS value of 76.2 ± 5.6 μm. In terms of precision, TR provided the highest precision (P < .05) in all three clinical situations, with RMS values 76.7 ± 26 μm for P1, 46.8 ± 14.1 μm for P2, and 39.7 ± 9.1 μm for P3. Two optical impression systems (TR and TD) were superior to the other tested systems in most of the measurements. However, none of the tested systems was clearly superior with respect to both trueness and precision.

Predictive factors of tumor sink effect: Insights from 177Lu-Prostate-specific membrane antigen therapy.

Tumor sink effect (TSE) has been defined as; decreased uptake in healthy tissue with increased tumor sequestration of the radiopharmaceuticals. It enables us to give high tumoral radiation doses while resulting in lower absorbed radiation to critical organs. However, the factors which influence this effect are yet to be defined. In this study, we have investigated the predictive factors of the tumor sink effect in a group of patients who received 177Lu-Prostate-specific membrane antigen (PSMA) therapy due to progressive metastatic castration-resistant prostate cancer (mCRPC). We have retrospectively analyzed the pre-therapy 68Ga-PSMA positron-emission tomography (PET)-computed tomography (CT) and post-therapy planar whole-body scans of 65 patients who received at least two cycles of 7.4GBq of 177Lu-PSMA therapy. All patients with mCRPC were referred to our department after multiple treatment lines. Age, previous therapies, International Society of Urological Pathology (ISUP) score, and pre-therapy serum tumor marker levels were recorded. Post 177Lu-PSMA therapy images were analyzed for TSE. 68Ga-PSMA PET-CT images were used for the calculation of SUVmax in malignant and healthy tissues as well as metabolic tumor volume (MTV) and total lesion PSMA index (TLPI). Based on the post-therapy scans, TSE was seen in 17/65 (26.2%) patients. In univariate analysis, patients with TSE had higher pre-therapy PSA, PSA velocity, and ALP (p < 0.0001). In relation to PET parameters, patients with TSE had higher 68Ga-PSMA MTV, 68Ga-PSMA TLPI and lower pretherapy renal SUVmax (p < 0.0001)), pretherapy liver SUVmax (p:0.012), pretherapy parotid gland SUVmax (p:0.032), and pretherapy parotid gland SUVmean (p:0.038). In the multivariant analysis, 68Ga-PSMA TLPI, pre-therapy PSA, and PSA velocity were found to be statistically significant. When analyzed according to Youden index, pretherapy PSA level of 133ng/ml (sensitivity 0.765 and 0.875), PSA velocity of 246ng/ml/year (sensitivity 0.765 and 0.833), and 68Ga-PSMA TLPI of 2969g (sensitivity 0.765 and 0.875) was found to be the best cut-off points to predict TSE. The tumor sink effect was seen in 26.2% of patients. 68Ga- PSMA TLPI, pre-therapy PSA, and PSA velocity was found to be the predictors of TSE. Accurate prediction of TSE may lead to increased tumoral doses while sparing healthy organs. Clinical trials that consider this effect as a part of a dose algorithm may further increase therapeutic efficacy.

Diagnostic and prognostic value of 99mTc-MAA SPECT/CT for treatment planning of 90Y-resin microsphere radioembolization for hepatocellular carcinoma: comparison with planar image

99mTc-macroaggregated albumin (MAA) imaging is performed before transarterial radioembolization (TARE), in which SPECT/CT is presumed more precise than planar image. However, additive role of SPECT/CT has not been well established. Thirty-four consecutive hepatocellular carcinoma patients of intermediate and advanced stages who underwent 90Y-microsphere TARE were recruited. On pre-treatment planning scan using 99mTc-MAA, image characteristics and absorbed dose for target tumors calculated by partition model methods were estimated on planar image and SPECT/CT, respectively. The measurements were repeated on post-treatment 90Y PET/CT, as the reference standard. Treatment response was assessed and predictive values of image parameters were analyzed. The image characteristics including heterogeneity, necrosis and thrombosis uptake were better delineated on SPECT/CT than planar scan. The agreement and correlation of TNr between SPECT/CT and PET/CT were stronger than those between planar scan and PET/CT. Tumor dose estimated on 99mTc-MAA SPECT/CT was more effective than planar image for prediction of treatment response, with cutoff value 125 Gy (sensitivity of 86% and specificity of 75%). In conclusion, 99mTc-MAA SPECT/CT is more closely correlated with post-treatment 90Y PET/CT, and is more effective for predicting treatment response than planar scan. SPECT/CT is superior to planar image in simulation before 90Y TARE.

Influence of Age, Estrogen receptor (ER),Progesterone receptor (PR) and Epidermal growth factor -2 (HER-2) in Breast Carcinoma Patient in correlation with Radionuclide Bone Scan – Single Institute Based Experience

Background: Breast carcinoma is a common type of malignancy in women worldwide. Radionuclide bone scintigraphy is recognized choice of investigation for the detection of bone metastases both in asymptomatic and symptomatic patients. Biomarkers like Estrogen Receptor (ER), Progesterone Receptor (PR), Human Epidermal growth factor -2 (HER-2) also play important role in the management and prognosis of breast cancer. The study was aimed to find out the relationship between the MDP bone scan findingsand hormone receptor and HER-2 status of breast carcinoma patients referred to the Institute of Nuclear Medicine and Allied Sciences (INMAS), Mitford, Dhaka.&#x0D; Patients and Methods: This cross sectional study was conducted among 301 breast carcinoma patients between January 2018 and December 2019. Planar bone scan and SPECT (if needed) was done to all the patients after intravenous injection of 99mTc-MDP. Receptor status (ER, PR and HER-2) were documented from the patient’s medical records. Breast tumors were classified as (a) Triple positive- HER2-, ER-, and PR-positive) (b) Triple negative- HER2-, ER-, and PR-negative (c) Hormonereceptor (HR) positive (ER+/PR+) with HER-2 negative and d) HR negative (ER-/PR-) with HER-2 positive.Patients were broadly grouped according to age as A. less than 50 years (n = 59) and B. more than 50 (n = 260 ) years.&#x0D; Results: The mean age of the patients enrolled for this study was 59.02±9.3 with range of 32 to 81 years. Out of the 301 patients, positive bone scans were found in 105 (34.8%) and negative bone scan were found 196 (66.2%). Patients of group A (&lt;50years) with triple negative and HR+/HER-status had no bone or bone with visceral metastases. Triple positive subtype had 2 bone metastases, and HR-/HER-2+ subtype had 2 bone metastases and 1 had bone with visceral metastases. Group B (&gt; 50years) patients having HR+/HER2- receptor status showed 16% solitary metastases, 53.2% multiple metastases, 33.3% extensive bony metastases, 13.6% bone with visceral metastases. Triple negative subtype showed 36.0 % solitary metastases, 19.1% bone with visceral metastases. Triple positive subtype group had 40.0% solitary metastases, 34.0 % multiple metastases, 66.7% extensive bony metastases, and 13.6% bone with visceral metastases. HR-/HER-2+ subtype group had 8% solitary metastases, 12.8% multiple metastases, and 18.2 % bone metastases with visceral involvement Overall relationship between bone scan and hormone receptor subtype, showed that most of the patients had HR+/ HER-2-(35.2%) subtype and 25.6% patient had triple positive, 23.3% patient had triple negative and 15.9% patient had HR-/HER-2 – receptor subtype. This study showed the visceral involvement with bone metastases (13 % in HR+/HER-2- 52.2 % in triple negative, 13 % in triple positive, 21.7 % in HR-/HER-2+subtype). Highest bone only metastases (35) in triple positive and HR+/HER-2-(31) subtype. Most of the patiens who had bone metastases with visceral involvement belong to triple negative (52.2%) and HER-2 subtypes -HR-/HER-2+ (21.7%). The result was significant (P&lt;0.001).&#x0D; Conclusion: It is observed from this study that triple positive and HR+/HER-2- were more likely to develop bone metastases than triple negative and HR-/HER-2-. Patients with bone scan negative and HR-/HER-2- or triple negative receptor status most likely develop visceral metastases&#x0D; Bangladesh J. Nuclear Med. 22(2): 114-118, Jul 2019

Development of raster scanning IMRT using a robotic radiosurgery system.

Treatment time with the CyberKnife frameless radiosurgery system is prolonged due to the motion of the robotic arm. We have developed a novel scanning irradiation method to reduce treatment time. We generated treatment plans mimicking eight-field intensity-modulated radiotherapy (IMRT) plans generated for the Novalis radiosurgery system. 2D dose planes were generated with multiple static beam spots collimated by a fixed circular cone. The weights of the uniformly distributed beam spots in each dose plane were optimized using the attraction–repulsion model. The beam spots were converted to the scanning speed to generate the raster scanning plan. To shorten treatment time, we also developed a hybrid scanning method which combines static beams with larger cone sizes and the raster scanning method. Differences between the Novalis and the scanning plan’s dose planes were evaluated with the criterion of a 5% dose difference. The mean passing rates of three cases were > 85% for cone sizes ≤ 12.5 mm. Although the total monitor units (MU) increased for smaller cone sizes in an inverse-square manner, the hybrid scanning method greatly reduced the total MU, while maintaining dose distributions comparable to those with the Novalis plan. The estimated treatment time of the hybrid scanning with a 12.5 mm cone size was on average 22% shorter than that of the sequential plans. This technique will be useful in allowing the CyberKnife with conventional circular cones to achieve excellent dose distribution with a shortened treatment time.

Assessment of cardiac amyloidosis with 99mTc-pyrophosphate (PYP) quantitative SPECT

Background99mTc-PYP scintigraphy provides differential diagnosis of ATTR cardiomyopathy (ATTR-CM) from light chain cardiac amyloidosis and other myocardial disorders without biopsy. This study was aimed to assess the diagnostic feasibility and the operator reproducibility of 99mTc-PYP quantitative SPECT.MethodThirty-seven consecutive patients who underwent a 99mTc-PYP thorax planar scan followed by SPECT and CT scans to diagnose suspected ATTR-CM were enrolled. For the quantitative SPECT, phantom studies were initially performed to determine the image conversion factor (ICF) and partial volume correction (PVC) factor to recover 99mTc-PYP activity concentration in the myocardium for calculating the standardized uptake value (SUV) (unit: g/ml). SUVmax was compared among groups of ATTR-CM, AL cardiac amyloidosis, and other pathogens (others) and among categories of Perugini visual scores (grades 0–3). The intra- and inter-operator reproducibility of quantitative SPECT was verified, and the corresponded repeatability coefficient (RPC) was calculated.ResultsThe ICF was 79,327 Bq/ml to convert count rate in pixel to 99mTc activity concentration. PVC factor as a function of the measured activity concentration ratio in the myocardium and blood-pool was [y = 1.424 × (1 − exp(− 0.759 × x)) + 0.104]. SUVmax of ATTR-CM (7.50 ± 2.68) was significantly higher than those of AL (1.96 ± 0.35) and others (2.00 ± 0.74) (all p < 0.05). SUVmax of grade 3 (8.95 ± 1.89) and grade 2 (4.71 ± 0.23) were also significantly higher than those of grade 1 (1.92 ± 0.31) and grade 0 (1.59 ± 0.39) (all p < 0.05). Correlation coefficient (R2) of SUVmax reached 0.966 to 0.978 with only small systematic difference (intra = − 0.14; inter = − 0.23) between two repeated measurements. Intra- and inter-operator RPCs were 0.688 and 0.877.Conclusions99mTc-PYP quantitative SPECT integrated with adjustable PVC factors is feasible to quantitatively and objectively assess the burden of cardiac amyloidosis for diagnosis of ATTR-CM.

The diagnostic incremental value of 131I SPECT-CT scan compared to planar 131I WBS for differentiated thyroid carcinoma: A single institutional experience

ABSTRACT This study investigated the usefulness of iodine-131 (131I) single-photon emission computed-tomography/computed-tomography (SPECT-CT) in conjunction with whole-body scan (WBS) planar imaging for the management of a patient presenting with differentiated thyroid carcinoma (DTC). A total of 100 patients with DTC post-total thyroidectomy were included in the study. The foci of 131I uptake were classified as neck site and outside the neck site by WBS planar and SPECT-CT imaging. SPECT-CT incrementally identified 141 neck sites and 217 distant neck foci compared to 139 at the neck site and 197 at the outside neck site identified by planar imaging. For the neck site, SPECT-CT downstaged 27 foci of 32 for indeterminate thyroid remnants at the neck site. Regarding sites distant to the neck, the SPECT-CT analysis led to the correct downstaging of two false-positive foci of suspicious uptake within the lung and bone, which were noted as metastases on planar images. SPECT-CT correctly upstaged one focus of iodine activity observed in the left arm as contamination on planar images, subsequently corrected as a metastatic bone lesion. The use of 131I SPECT-CT scans increased the incremental diagnostic data compared with 131I WBS planar scan imaging alone, which could change patient management.

Robotically‐controlled antenna measurement system for millimeter‐wave applications

AbstractThe characterization of antenna radiation patterns in millimeter‐wave (mmW) bands can be particularly challenging. Due to a small wavelength, minute misplacement of the probe antenna in the order of few millimeters can generate substantial errors in the measured pattern. A highly precise measurement system that incorporates a 6‐axis compact robotic arm is implemented to overcome this challenge. System testing shows a positional accuracy and repeatability of approximately 20 μm or 0.004λ at 60 GHz. After implementation, programming, and testing, the system is used to measure gain patterns on three different mmW antennas. The radiation pattern of a 50–75 GHz standard gain horn antenna demonstrated the accurate measurement at the far‐field using the robotically controlled system. Furthermore, the characterization of the center element pattern of a 60 GHz phased array has shown that the measurements with this system are repeatable and suitable for arrays as well. Additionally, we performed near‐field measurements by successfully characterizing a 40–60 GHz horn antenna with a planar scan.

Interrater Reliability of 99mTc-DMSA Scintigraphy Performed as Planar Scan vs. SPECT/Low Dose CT for Diagnosing Renal Scarring in Children.

99mTc-dimercaptosuccinic acid (DMSA) scintigraphy is currently the method of choice for assessing renal scarring in children, but it is not established whether conducting the scan as a single photon emission tomography combined with low-dose CT (SPECT/ldCT) scan provides additional diagnostic benefits when compared to conventional planar scintigraphy. In the present study, we evaluated the interrater reliability of DMSA SPECT/ldCT vs. planar DMSA scintigraphy for diagnosing renal scarring. Methods: Two nuclear medicine physicians blinded to patient data retrospectively analysed all paediatric 99mTc-DMSA scintigraphes that were conducted in our department for the assessment of post pyelonephritis renal scarring between 2011 and 2016. All scintigraphies included both a planar scan and SPECT/ldCT, and were performed on either a Phillips Precedence 16 slice CT or a Siemens Symbia 16 slice CT. The readers were blinded to each other’s readings and to patient data, and assessed all scans dichotomously for evidence of renal scarring. For each scan, the readers further noted if they were confident in their interpretation. Results: A total of 46 pairs of planar SPECT/ldCT DMSA scans were included. The readers were unconfident about their interpretation of 40% of the planar scans and 5% of the SPECT/ldCT scans. The interrater agreement rate was 72% for planar scans and 91% for SPECT/ldCT, and the corresponding Cohen’s kappa values were 0.38 and 0.79. Conclusion: DMSA SPECT/ldCT is associated with higher reader confidence and interrater reliability than conventional planar DMSA scintigraphy for the assessment of post pyelonephritis renal scarring in children.

Robotic Navigated Laser Craniotomy for Depth Electrode Implantation in Epilepsy Surgery: A Cadaver Lab Study.

Depth electrode implantation for invasive monitoring in epilepsy surgery has become a standard procedure. We describe a new frameless stereotactic intervention using robot-guided laser beam for making precise bone channels for depth electrode placement. A laboratory investigation on a head cadaver specimen was performed using a CT scan planning of depth electrodes in various positions. Precise bone channels were made by a navigated robot-driven laser beam (erbium:yttrium aluminum garnet [Er:YAG], 2.94-μm wavelength,) instead of twist drill holes. Entry point and target point precision was calculated using postimplantation CT scans and comparison to the preoperative trajectory plan. Frontal, parietal, and occipital bone channels for bolt implantation were made. The occipital bone channel had an angulation of more than 60 degrees to the surface. Bolts and depth electrodes were implanted solely guided by the trajectory given by the precise bone channels. The mean depth electrode length was 45.5 mm. Entry point deviation was 0.73 mm (±0.66 mm SD) and target point deviation was 2.0 mm (±0.64 mm SD). Bone channel laser time was ∼30 seconds per channel. Altogether, the implantation time was ∼10 to 15 minutes per electrode. Navigated robot-assisted laser for making precise bone channels for depth electrode implantation in epilepsy surgery is a promising new, exact and straightforward implantation technique and may have many advantages over twist drill hole implantation.

Алгоритм восстановления источников электромагнитного излучения от печатной платы в ближней зоне.

This article presents an algorithm for recovering radiation sources from a printed circuit board in the near field. The model of the printed circuit board is represented by the Hertz dipoles, the equations for which are known. The basis of the reconstruction algorithm is LASSO regression, which allows one to recover the parameters of radiation sources with a higher accuracy than the classical Tikhonov regularization method widely used in similar problems. To use the reconstruction algorithm, it is necessary to have experimental data on electromagnetic radiation from the printed circuit board. Such data can be obtained using a planar scan method. This article presents the experimental results of reconstructing radiation sources from a printed circuit board using the proposed algorithm.

Deep Inspiration Breath-Hold (DIBH) for Locoregional Breast Irradiation using Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Proton Therapy (IMPT): A Dosimetric Comparison to Cardiac Substructure

Conventional breast irradiation with tangent fields poses cardiotoxicity risks but recent techniques significantly reduce heart exposure, such as rotational intensity modulated radiation therapy or proton therapy. This study evaluates the potential of deep inspiration breath-hold (DIBH) combination with volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) for further cardiac sparing, at the cardiac substructure level. Following breast conserving surgery, 14 left-sided breast cancer patients treated with free breathing (FB)-VMAT (n = 7) or DIBH-VMAT (n = 7) were retrospectively included. Patients were treated to a dose of 51.8Gy to the whole left breast, 50.4 Gy to the axillary and internal mammary nodes, and 63 Gy to the tumor bed. Pencil beam scanning plans were generated on the initial simulation FB or DIBH computed tomography scans with similar PTV coverage constraints. The endpoint was the mean dose to the heart, to the cardiac cavities, to the left ventricle walls and to the coronary arteries. Table 1 presents the mean doses to cardiac substructures using VMAT and IMPT, with or without DIBH. When combined with VMAT, DIBH significantly reduces dose to nearly all cardiac substructures and to all coronary artery segments. In contrast, when combined with IMPT, DIBH does not show any dosimetric benefit. FB-IMPT significantly spares cardiac substructures compared with DIBH-VMAT. Contrasting with VMAT irradiation where DIBH significantly reduces doses delivered to nearly all cardiac substructures, DIBH does not seem to demonstrate a dosimetric benefit when combined with IMPT. DIBH is thus probably unnecessary for locoregional breast irradiation with IMPT.Abstract 2091; TableStructureVMAT (mean dose Gy)IMPT (mean dose Gy)Free BreathingDIBHp valueFree BreathingDIBHp valueHeart7.123.500.010.800.320.05Left ventricle7.403.19<0.010.090.220.09Anterior wall12.475.23<0.010.260.720.18Apical wall12.384.390.010.400.880.20Lateral wall6.603.37<0.010.040.160.02Inferior wall4.131.65<0.02<0.010.010.47Septal wall6.622.77<0.030.020.010.36Right ventricle7.053.55<0.040.790.070.14Left auricle3.971.910.02<0.01<0.010.08Right auricle3.892.440.040.060.030.13Left main coronary artery6.342.85<0.010.02<0.010.37Left anterior descending artery21.198.32<0.012.481.650.47Proximal segment12.995.170.040.190.290.63Mid segment24.1010.88<0.014.003.130.68Distal segment23.528.370.012.151.380.35Circumflex artery5.122.540.03<0.01<0.010.11Proximal segment7.343.090.02<0.010.010.22Distal segment4.532.410.06<0.01<0.010.10Right coronary artery5.402.870.010.030.060.62Proximal segment6.454.580.220.060.140.59Mid segment4.152.270.050.01<0.010.29Distal segment3.011.170.01<0.01<0.010.36Posterior descending segment6.151.560.01<0.01<0.010.18Author Disclosure: P. Loap: None. F. Goudjil: None. B. Baron: None. M. Ribeiro: None. A. Fourquet: None. Y. Kirova: None. Open table in a new tab

Rest/stress intradermal lymphoscintigraphy in diagnosis of lipedema.

Lipedema is a chronic and progressive disease characterized by a symmetrical and bilateral swelling of the lower extremities. In general, the feet are not involved. Lipedema is believed to affect nearly 1 in 9 adult women worldwide. Despite this relatively common disease, lipedema is often confused with primary lymphedema or obesity. In clinically advanced lipedema stages, fat continues to build up and may block the lymphatic vessels causing a secondary lymphedema (Lipo-Lymphedema). We consecutively evaluated 54 women with a clinical diagnosis of lower limbs lipedema. Two doses of 99mTc-nanocolloid were injected intradermally at the first intermetatarsal space and in the lateral malleolar area. Two static planar scans were taken at rest immediately following the intradermal injection. Subsequently, all patients were asked to perform an isotonic muscular exercise (stepping) for 2 min. Then, post exercise scans were performed to monitor the tracer pathway. Subsequently, the patient was asked to take a 30–40 min walk (prolonged exercise) and delayed scans were acquired. In early clinical stages, the lymphatic flow is usually preserved and the rest/stress intradermal lymphoscintigraphy may visualize a normal lymphatic drainage with a frequent pattern (tortuous course) of the leg lymphatic pathway. In clinically advanced stages, lymph stagnation areas were observed. Unlike obesity, lipedema fat storage is resistant to dietary regimen, bariatric surgery, and physical activity. Surgical treatment (tumescent liposuction and reductive surgery) is the most effective treatment to remove adipose tissue. Complex decongestive therapies are helpful in reducing the lymph stagnation, especially in patients with advanced lipolymphedema.

Analysis of Bone Scans in Various Tumor Entities Using a Deep-Learning-Based Artificial Neural Network Algorithm-Evaluation of Diagnostic Performance.

Simple SummaryStandardized reading schemes, the use of indicators derived from medical images and the use of deep learning-based algorithms become very popular in medical imaging. In this retrospective study, we evaluated the performance of an automatic deep-learning-based algorithm for computer-assisted diagnosis in the field of oncological whole-body bone imaging in nuclear medicine. In addition to prostate cancer, representing a tumor entity evaluated thoroughly using the examined methodology (Bone Scan Imaging (BSI) methodology), a modification of the BSI based standard rating scheme facilitate the use of the methodology for other tumor entities (e.g., breast cancer, lung cancer, hepatocellular carcinoma). Diagnostics in clinical routine can benefit from the examined methodology, mainly due to its sensitivity and the high negative predictive value. Non-pathological bone scans may be easily identified. This may lead to a reduced working load in nuclear medicine departments and may result in an improved and more standardized workflow.The bone scan index (BSI), initially introduced for metastatic prostate cancer, quantifies the osseous tumor load from planar bone scans. Following the basic idea of radiomics, this method incorporates specific deep-learning techniques (artificial neural network) in its development to provide automatic calculation, feature extraction, and diagnostic support. As its performance in tumor entities, not including prostate cancer, remains unclear, our aim was to obtain more data about this aspect. The results of BSI evaluation of bone scans from 951 consecutive patients with different tumors were retrospectively compared to clinical reports (bone metastases, yes/no). Statistical analysis included entity-specific receiver operating characteristics to determine optimized BSI cut-off values. In addition to prostate cancer (cut-off = 0.27%, sensitivity (SN) = 87%, specificity (SP) = 99%), the algorithm used provided comparable results for breast cancer (cut-off 0.18%, SN = 83%, SP = 87%) and colorectal cancer (cut-off = 0.10%, SN = 100%, SP = 90%). Worse performance was observed for lung cancer (cut-off = 0.06%, SN = 63%, SP = 70%) and renal cell carcinoma (cut-off = 0.30%, SN = 75%, SP = 84%). The algorithm did not perform satisfactorily in melanoma (SN = 60%). For most entities, a high negative predictive value (NPV ≥ 87.5%, melanoma 80%) was determined, whereas positive predictive value (PPV) was clinically not applicable. Automatically determined BSI showed good sensitivity and specificity in prostate cancer and various other entities. Particularly, the high NPV encourages applying BSI as a tool for computer-aided diagnostic in various tumor entities.

Improved Component Placement Accuracy with Robotic-Arm Assisted Total Knee Arthroplasty.

Component position of total knee arthroplasty (TKA) has been shown to influence prosthetic survivorships and clinical outcomes. Our objective was to compare the three-dimensional accuracy to plan of robotic-arm assisted TKA (RATKA) with conventional TKA for component position. We conducted a nonrandomized, prospective study comparing 143 RATKA with 86 conventional TKA operated at four U.S. centers between July 2016 and October 2018. Computed tomography (CT) scans obtained approximately 6 weeks postoperatively were analyzed using anatomical landmarks. Absolute deviation from surgical plans were defined as the absolute value of the difference between the CT measurements and surgeons' femoral and tibial component mechanical varus/valgus alignment, tibial component posterior slope, and femoral component internal/external rotation. Differences of absolute deviations were tested using stratified Wilcoxon's tests that controlled for study center. Patient-reported outcome measures collected through 1 postoperative year were modeled using multiple regression controlling for age, sex, body mass index, study center, and the preoperative score. RATKA demonstrated greater accuracy for tibial component alignment (median [25th, 75th percentiles] absolute deviation from plan of all centers combined for conventional vs. RA, 1.7 [0.9, 2.9] vs. 0.9 [0.4, 1.9] degrees, p < 0.001), femoral component rotation (1.5 [0.9, 2.5] vs. 1.3 [0.6, 2.5] degrees, p = 0.015), and tibial slope (2.9 [1.5, 5.0] vs. 1.1 [0.6, 2.0] degrees, p < 0.001). In multivariable analyses, RATKA showed significantly greater Veterans RAND 12-item health survey (VR-12) physical component scores (adjusted mean difference [95% confidence interval (CI)]: 2.4 [0.2, 4.5] points, p = 0.034) and qualitatively greater Knee Society (KS) composite functional scores (3.5 [-1.3, 8.2] points, p = 0.159), though not statistically significant. Compared with conventional instrumentation, RATKA demonstrated greater three-dimensional accuracy to plan for various component positioning parameters and clinical improvements in physical status and function with no major safety concerns during the first postoperative year. These results may be attributed to the preoperative CT scan planning, real-time intraoperative feedback, and stereotactic-guided cutting that takes into consideration patient-specific bony anatomy. These findings support the use of RATKA for enhanced arthroplasty outcomes.