Breast Dose Research Articles

Trade-off between breast dose and image quality using composite bismuth shields in computed tomography: A phantom study

IntroductionMany researchers have suggested that bismuth composite shields (BCS) reduce breast dose remarkably; however, the level of this reduction and its impact on image quality has not been assessed. This study aimed to evaluate the efficiency of nano- and micro- BCS in reducing the dose and image quality during chest computed tomography (CT) scans. Materials and methodsBismuth shields composed of 15 weighting percentage (wt%) and 20 wt% bismuth oxide (Bi2O3) nano- and micro-particles mixed in silicon rubber polymer were constructed in 1 and 1.5 mm thicknesses. The physical properties of nanoparticles were assessed using a scanning electron microscope (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX). Breast radiation doses were measured experimentally during chest CT using PMMA standard dosimetry phantom (body phantom, 76-419-4150, Fluke Biomedical) in the presence of the shields. The image quality was assessed by calculating signal and noise values in different regions. ResultsThe SEM images showed that the average size of Bi2O3 nano- and micro-particles was about 70 nm and 150 μm, respectively. The breast doses were reduced by increasing the shield thickness/bismuth weight percentage. The maximum dose reduction was related to the 20% weight of Bi2O3 nano-particles and a thickness of 1.5 mm. The minimum dose reduction was related to the 15% weight of Bi2O3 micro-particles with a thickness of 1 mm. The mean noise was higher in nano-particle bismuth shields than in micro-particles. ConclusionComposite shields containing bismuth nano- and micro-particles can reduce the breast dose during chest CT examinations while negatively impacting diagnostic image quality. Several critical factors, such as bismuth concentration, particle size, and shield thickness, directly affect the efficiency.

Evaluation of silicon and 10% bismuth shield with variable thickness compared with constant thickness on the dose reduction and image quality during chest CT examination

One of the best methods to reduce the breast radiation dose in chest CT scan exam is using the bismuth shield. Due to the fact that, in CT scan tests, the breast dose is higher in the central axis of body than other sides, so the bismuth shield with variable thickness (outer half 1 mm thick and inner half 2 mm thick) is designed in this study. The objective of this study is to investigate in effectiveness of silicon and 10% bismuth composite shied with variable thickness on reducing radiation dose and image quality parameters in chest CT scan test compare to 1 mm and 2 mm of fixed thickness shield. Physical chest phantom underwent chest CT scan without or with bismuth shields with thickness of 1 mm, 2 mm, and variable in 90, 120 and 140 kVp in inactive TCM mode. Dosimetry was performed by using TLD, and image quality was evaluated quantitatively (by drawing the ROI in the identical images like image j, calculation of noise, CT number, SNR and CNR) and qualitatively (by two expert radiologists). Designed bismuth shield with unsteady thickness in inner and outer side compare to 1 mm and 2 mm thickness shields is presented in 120 kVp, has a significant difference in the amount of breast dose reduction (19% reduction), as well as in 140 kVp, all these three bismuth shields resulted in a significant dose reduction almost in the same similarity. At 120 kVp, the bismuth shield with variable thickness lead to a significant change in CT numbers in the heart and lungs, but it does not have a remarkable effect on other image quality parameters. The bismuth shield with variable thickness can lead to a better effectiveness in reducing breast dose without any side effect on image quality at 120 kVp, which requires further studies in this field.

Targeted Sensitization of Glioblastoma Multiforme Using AAAPT Technology.

Glioblastoma Multiforme (GBM) is the most malignant type of all brain tumors. Current GBM treatment options include surgery, followed by radiation and chemotherapy. However, GBM can become resistant to therapy, resulting in tumor recurrence. GBM cells develop resistance to treatments by either downregulating cell death pathways (CD95) or upregulating cell survival pathways (NF-κB (p65)). Healthy tissues can be affected by the increased therapeutic dose. Therefore, it is important to develop a method that can only target GBM tumor cells, thereby reducing the non-specific uptake which will reduce the side effects. Here we demonstrate an application of novel priori activation of apoptosis pathways of tumor technology (AAAPT), which has been used to demonstrate the effect of targeted tumor sensitizers to make chemotherapy work at lower doses in breast, lung and prostate cancers. Treatment of GBM spheroids with AAAPT in 3D PEGDA microwells, showed an increase in cell death, an upregulation of cell death pathways, and a downregulation of cell survival pathways, in comparison to Temozolomide (TMZ), an oral alkylating agent, which is a commonly used chemotherapy in the treatment of GBM. The dose of AAAPT sensitizers may provide a promising method to increase treatment efficacy and reduce off-target toxicity, as an alternative to existing methods which cause significant off-target damage.

Dose-reduction Efficiency by Breast Compression in Digital Mammography

Although breast compression has been an efficient practice to reduce the breast dose in mammography, there may be some differences between analog and digital systems. The purpose of this study was to evaluate the dose-reduction efficiency by breast compression in digital mammography under its own criterion that signal difference-to-noise ratio (SDNR) be kept at a certain value. By adopting SDNR as an image quality indicator and average glandular dose (AGD) as a dose indicator, we measured SDNR versus AGD relationship for each breast depth. Then by utilizing figure of merit (FOM), we calculated the breast depth that we had to reduce for halving the breast dose while keeping the SDNR. To halve the dose, 1.49 cm compression was necessary for 0% breast density, 1.25 cm for 50%, and 1.06 cm for 100%. Through FOM analysis, we quantitatively revealed the dose-reduction efficiency by breast compression in digital mammography.

Contralateral breast radiation doses in breast cancer patients treated with helical tomotherapy.

We aimed to evaluate contralateral breast doses calculated with a Treatment Planning System (TPS) and verified with metal oxide semiconductor field effect transistor (MOSFET) detectors in patients with early-stage breast cancer (BC) who received helical tomotherapy (HT) after breast-conserving surgery. The dosimetric data of 30 patients (15 left-sided and 15 right-sided) with BC treated with 50.4 Gy to the whole breast and 64.4 Gy to the tumor bed in 28 fractions were analyzed. TPS doses were calculated and MOSFET doses were measured in the contralateral breast (CB) at cranial, caudal, and midpoint and 2 cm lateral to the central point. TPS and MOSFET doses were compared in the entire cohort as well as by tumor location (inner vs outer quadrant) and planning target volume of the breast (<1200 cc vs ≥1200 cc). The average doses at superior, inferior, central, and lateral points calculated with the TPS were 0.26 ± 0.15 cGy, 0.21 ± 0.09 cGy, 0.65 ± 0.14 cGy, and 0.50 ± 0.11 cGy, respectively, and were 0.37 ± 0.16 cGy, 0.34 ± 0.12 cGy, 0.60 ± 0.18 cGy, and 0.34 ± 0.15 cGy, respectively in MOSFET readings. Except for the central point, TPS-calculated doses and MOSFET readings were differed. The doses to the CB in patients with inner and outer quadrant tumors were not significantly different. In patients with large breasts, MOSFET doses were higher at superior and lateral points than TPS doses, but TPS doses were greater at inferior points. MOSFET readings were higher than TPS calculated doses in patients with inner or outer quadrant tumors in small or large breast volumes. The dose calculated by the TPS and that measured by MOSFET differed by a very small amount. The maximum dose to the CB administered at the midpoint was 1.8 Gy, as calculated using the TPS and confirmed using MOSFET detectors, in patients with early-stage BC undergoing breast-only radiotherapy with HT.

The function of forward planned intensity-modulated radiotherapy technique in radiotherapy of the intact breast dose distribution optimization

The function of forward planned intensity-modulated radiotherapy technique in radiotherapy of the intact breast dose distribution optimization

Early Toxicity and Patient-Reported Cosmetic Outcomes in Patients Treated With Adjuvant Proton-Based Radiotherapy After Breast-Conserving Surgery

IntroductionTo evaluate the dosimetric data, early toxicity, and patient-reported cosmetic outcomes in breast cancer patients treated with adjuvant proton-based radiotherapy (RT) after breast-conserving surgery. Materials and MethodsWe performed a retrospective review of our institutional database to identify breast cancer patients treated with breast-conserving surgery followed by proton-based RT from 2015 to 2020. Patient-reported cosmetic outcomes were graded as excellent, good, fair, or poor. Early toxicity outcomes were graded by the treating physician during treatment. Dose-volume histograms were reviewed to obtain dosimetry data. ResultsWe identified 21 patients treated with adjuvant proton-based RT. Median whole breast dose delivered was 46.8 Gy (range, 40.0-50.4 Gy). Target volumes included the regional lymph nodes in 17 patients (81%). Seventeen patients (81%) received a lumpectomy boost. The median planning target volume V95 was 94% (range, 77%-100%), V100 71% (range, 60%-97%), V110 2% (range 0%-18%), and median max point dose was 115% (range, 105%-120%). The median ipsilateral breast V105 was 367.3 cc (range, 0-1172 cc) and V110 was 24.1 cc (range, 0-321.3 cc). Grade 2 and 3 dermatitis occurred in 62% and 14% of patients, respectively. Grade 2 and 3 pain was reported by 33% and 10% of patients, respectively. Median follow-up at the time of cosmetic evaluation was 27 months (range, 5-42 months). Four patients (21%) reported fair cosmetic outcome and 15 patients (79%) reported good or excellent cosmetic outcome. No poor cosmesis was reported. ConclusionAdjuvant proton-based radiotherapy after breast-conserving surgery is well tolerated with acceptable rates of acute toxicities and a high rate of good-to-excellent patient-reported cosmetic outcomes.

Accuracy of patient dose estimation in cone beam computed tomography in breast irradiation by size-specific dose estimates with position correction.

This study aims to investigate the effects of the position correction of size-specific dose estimates (SSDE) on patient dose estimation in cone beam computed tomography (CBCT). The relationship between the phantom position and absorbed dose in the right breast was studied using optically stimulated luminescence dosimeters and a simulated human body phantom. The effect of position correction for CT dose index (CTDI) on SSDE was investigated in 51 patients who underwent right breast irradiation by comparing the SSDE with position correction and SSDE without position correction. The absorbed dose in the right breast tended to decrease by 10.2% as the phantom was placed away from the center of CBCT. The mean and standard deviation of SSDE were 2.54±0.29 and 2.92±0.30 mGy with and without position correction, respectively. The SSDE with position correction was 13.1% lower than that without position correction (p<0.05). SSDE was different when the patient's torso center was located at the isocenter of CBCT, and when it was not. The same tendency was seen in the case of the breast. Therefore, if the center of the patient is not at the acquisition center of the CT scanner, position correction is required when estimating SSDE.

Doxorubucin loaded pH-responsive chitosan-poly(acrylamide-maleic acid) composite hydrogel for anticancer targeting

A pH responsive superadsorbent composite hydrogel, chitosan-poly(acrylamide-maleic acid)(Ch-p(Ac-Ma)), were synthesized, characterized and loaded by Doxorubucin (Dox), anti-cancer drug. Chitosan solution was modified by blending biocompatible chitosan and poly(acrylamide-co-maleic acid) in the polymerization medium. This new composite hydrogel had a high loading capacity for Dox (∼90%). Some chemical characteristics of the prepared composite hydrogel were investigated by swelling test, SEM, FTIR, XRD. The drug release study confirmed the pH-responsive delivery of doxorubucin. The composite hydrogel was loaded by high efficiency and the release experiments exhibited that Dox is released more at pH 4.5 compared with pH 7.4 at 37 °C. The biocompatibility of the prepared composite hydrogel was demonstrated via XTT assay in MCF-7 cells. The Dox loaded composite showed a controlled release, especially at acidic region. The Ch-p(Ac-Ma) exhibited a good biocompatibility against breast cancer cells (MCF 7) and dose dependent drug delivery behavior. Also, we employed molecular docking and density functional theory analysis to investigate the inhibitory activity, reactivity, and stability of Doxorubucin and target protein HER2 ((Pdb ID: 7JXH). The interaction between Doxorubucin and target protein HER2 ((Pdb ID: 7JXH) was investigated in the light of Molecular Docking calculations.

Dosimetric Variables and Clinical Correlation of Toxicities and Breast Cosmesis in Adjuvant Hypofractionated Whole Breast Irradiation Using Field in Field 3DCRT

<h3>Purpose/Objective(s)</h3> The objective of our study was to assess the change in breast cosmesis, Acute skin toxicity, Late Skin Toxicity, Late Subcutaneous Tissue Toxicity at different points of time in patients receiving adjuvant Hypofractionated Whole Breast Radiotherapy schedule (HF-WBRT) and to find out any existing relation with any other dosimetric variables responsible for their outcomes. <h3>Materials/Methods</h3> The START B protocol for dose fractionation was followed. The cosmetic outcome of the patients was assessed using the Harvard Breast Cosmesis Grading Scale. Similarly, Acute toxicities, Late skin toxicities, Late subcutaneous tissue toxicities were recorded using the RTOG/EORTC scoring scheme. Data was generated on the different volumes of tissue receiving 95%,102%,105% and 107% of the prescribed dose respectively. Further, all these volumes were divided into two subgroups – dose volumes within the Whole Breast PTV and dose volumes outside the Whole Breast PTV. Multivariate Analysis of variables were done. Bivariate Correlations of differences were performed and outcomes were analyzed using Spearman's rho correlation coefficient test. We also ran the Binary Logistic Regression Analysis test for predicting the outcomes of interest with the different variables. <h3>Results</h3> 125 patients were accrued and analyzed for this study. For acute skin toxicity, significant positive correlations existed with the volume of tissue within the PTV receiving 95% (0.695) and 102% (0.430) and with the volume of tissue outside the PTV receiving 95% (0.333) of the prescribed dose. The volume of tissue outside the PTV receiving 102% had a significant predictive probability for acute skin toxicity [p=0.001, OR 1.056 (1.024-1.029)]. For late skin toxicity, a significant positive correlation existed with the volume of tissue within the PTV receiving 95% (0.465). For late subcutaneous tissue toxicity, there was a significant positive correlation with the volume of tissue within the PTV receiving 95% (0.516). Significant predictive associations were found with the volume of tissue within the PTV receiving 105% [p=0.014, OR 1.014(1.003-1.026)] and volume of tissue outside the PTV receiving 102 % [p=0.00, OR 1.052(1.025-1.080)]. For a change in breast cosmesis, Significant predictive associations were found with volume of tissue within the PTV receiving 95% [p=0.00, OR 1.006(1.004-1.009)] and 102% [p=0.02, OR 1.003(1.001-1.005)]. <h3>Conclusion</h3> The volume of tissue receiving more than 105% was found to be a factor for the development of late toxicities The volume of tissue outside the breast PTV receiving more than 102% also should be kept at a minimum as it had a significant association with both changes in breast cosmesis and with acute and late toxicities. Therefore, newer variables like excess dose above the prescribed dose received by tissue, outside the PTV, also needs to be looked into. This study thus hypothesizes use of more conformal planning techniques in whole breast irradiation.

Dosimetry Study of Radiation Toxicity in Young Patients with Mediastinal Lymphoma by the Use of an Inclined Board and Deep Inspiration Breath-Holding, under the Guidance of an Optical Surface Management System

<h3>Purpose/Objective(s)</h3> Survivors of mediastinal lymphoma are at increased risk of lung cancer, breast cancer, and cardiovascular disease after radiotherapy. We compared treatment plans for patients in one of two positions while using one of two breathing techniques: supine on an inclined board (IB) or flat; and using deep inspiration breath-hold (DIBH) or free-breathing. <h3>Materials/Methods</h3> Ten young patients with mediastinal lymphoma were eligible for the study. Sets of intensity-modulated radiation therapy (IMRT) treatment plans were created for each of 10 patients with mediastinal lymphoma (6 women, 4 men): DIBH-IB (for women); FB-IB (for women); DIBH-flat (for men); and FB-flat (for men and women). During DIBH, an optical surface management system (OSMS) was used to monitor breathing rate and magnitude, track respiratory status in real time. Tumor target volumes and organs at risk (OARs; lungs, breasts [in women], thyroid, and heart and its substructures) were compared in all four conditions. <h3>Results</h3> A total of 26 plans were created for all 10 patients. The DIBH-IB plan (for women) and the DIBH-flat plan (for men) was used for actual patient treatment. Daily pre-RT cone beam CT (CBCT) was used before treatment to adjust for set-up errors. Daily post-RT CBCT was used after treatment to assess intra-fractional variability. Registration of post-RT CBCT with the planning CT showed that both tumor and OARs matched well, with rather small intra-fractional variability. The planning target volume (PTV) was considerably smaller in the DIBH plans (380.0 cm³ for DIBH vs 527 cm³ for FB, <i>P</i><0.001), because of the smaller clinical target volume-to-PTV margins in the DIBH plans and the compression of the CTV due to the deep inspiration and breath hold. Plans for DIBH-IB for women and DIBH-flat for men produced lower mean lung dose (6.1 vs 8.1 Gy; <i>P</i><0.001), lung V5 (36.1% vs 47.9%; <i>P</i>=0.001), and lung V20 (7.9% vs 11.7%; <i>P</i><0.001) compared with FB-IB and FB-flat plans. Plans for FB-IB also resulted in smaller mean breast dose and breast V5 than FB-flat (3.4 vs 4.0 Gy, 16.3% vs 20.4%, <i>P</i>=0.018 and 0.008). Use of DIBH-IB reduced both measures still further relative to FB-flat (2.6 vs 4.0 Gy, 13.8% vs 20.4%, <i>P</i>=0.015 and 0.013). Plans for DIBH produced lower mean heart dose (8.7 vs 10.4Gy; <i>P</i>=0.048) and heart V5 (40.6% vs 55.4%; <i>P</i>=0.023) compared with FB plans. Use of DIBH brought more dosimetric benefits of mean dose, V5 and V20 to the right heart substructures including right ventricle, right atrium and right coronary artery. <h3>Conclusion</h3> In this small group of patients with mediastinal lymphoma, use of DIBH (with an OSMS) and an IB resulted in lower estimated doses to lungs, breasts and heart, especially the right heart, than did FB; these reduced doses may reduce the probability of pulmonary, breast and cardiac radiation toxicity.

Accelerated Partial Breast Irradiation: An Opportunity for Therapeutic De-escalation.

Partial breast irradiation (PBI) has been demonstrated to have comparable outcomes to whole breast irradiation based on multiple randomized trials with long-term follow-up. However, despite the strength of the data available, PBI remains underutilized despite being an appropriate option for many women diagnosed with early-stage breast cancer. This is significant, as PBI offers the potential to reduce toxicities and shorten treatment duration without impacting outcomes; in addition, for low-risk patients, PBI alone is being investigated as an alternative to endocrine therapy alone. Modern PBI can be delivered with multiple techniques, and advances in treatment planning have allowed for improved therapeutic ratios compared with earlier techniques; one such approach is utilizing stereotactic body radiation therapy approaches allowing for smaller target margins and therefore lower breast doses. Moving forward, studies are ongoing evaluating the use of radiation alone including PBI as compared with endocrine therapy alone, with prospective studies evaluating stereotactic body radiation therapy.

The Italian Association for Radiotherapy and Clinical Oncology (AIRO) position statements for postoperative breast cancer radiation therapy volume, dose, and fractionation

Recent advances in non-metastatic breast cancer radiation therapy significantly reshaped our views on modern dose and fractionation schedules. Especially the advent of hypofractionation and partial breast irradiation defined a new concept of treatment optimization, that should strongly include both patient and tumour characteristics in the physician’s decision-making process. Unfortunately, hypofractionation for breast cancer radiation therapy needed long time to enter the routine practice during the last decades despite the level-1 evidence published over time. Hereby we present the Italian Association for Radiotherapy and Clinical Oncology (AIRO) Breast Cancer Group position statements for postoperative breast cancer radiation therapy volume, dose, and fractionation to harmonically boost routine clinical practice implementation following evidence-based data.

Assessment of breast dose and cancer risk for young females during CT chest and abdomen examinations

CT scanning deliver much higher radiation doses than planar radiological procedures, which puts patients to high risks. This study measures and evaluates patient doses during chest and abdomen computed tomography procedures. Particular attention is given to measuring the dose to the equivalent breast (mSv) and to estimate the associated risks of breast cancer to young female patients (15–35 years). Data was obtained from standard examinations from three hospitals. The measured values of CT dose indexes, CTDI (mGy) as well as exposure-related parameters were used for assessment. Breast and effective doses were extrapolated using a software. The results showed remarkable variations of the mean organ equivalent doses for similar CT examinations in the studied hospitals. This could be attributed to the variation in CT scanning imaging technique, and clinical indications. The average effective dose to the chest was 7.9 mSv (2.3–47.0 mSv) and for the abdomen the mean dose was 6.6 mSv, ranging from (3.3–27 mSv). The breast received equivalent doses from chest and abdomen procedures as follows: 10.2 (1.6–33 mSv) and 10.1(2.3–19 mS) Sv respectively. Each procedure yielded high risks of breast cancer for young females. Implementation of accurate referral criteria is recommended to avoid unnecessary breast radiation exposure.

Breast Shielding Combined With an Optimized Computed Tomography Pulmonary Angiography Pregnancy Protocol: A Special Use-Case for Shielding?

To determine the impact of breast shields on breast dose and image quality when combined with a low-dose computed tomography pulmonary angiography (CTPA) protocol for pregnancy. A low-dose CTPA protocol, with and without breast shields, was evaluated by anthropomorphic phantom and 20 prospectively recruited pregnant participants from January to October 2019. Thermoluminescent dosimeters measured surface and absorbed breast dose in the phantom and surface breast dose in participants. The Monte-Carlo method estimated the absorbed breast dose in participants. Image quality was assessed quantitatively by regions of interest analysis and subjectively by the Likert scale. Doses and image quality for CTPA alone were compared with CTPA with breast shields. Mean surface and absorbed breast dose for CTPA alone were 1.3±0.4 and 2.8±1.5mGy in participants, and 1.5±0.7 and 1.6±0.6mGy in the phantom. Shielding reduced surface breast dose to 0.5±0.3 and 0.7±0.2mGy in the phantom (66%) and study participants (48%), respectively. Absorbed breast dose reduced to 0.9±0.5mGy (46%) in the phantom.Noise increased with breast shields at lower kV settings (80 to 100kV) in the phantom; however, in study participants there was no significant difference between shield and no-shield groups for main pulmonary artery noise (no-shield: 34±9.8, shield: 36.3±7.2, P =0.56), SNR (no-shield: 11.2±3.7, shield: 10.8±2.6, P =0.74) or contrast-to-noise ratio (no-shield: 10.0±3.3, shield: 9.3±2.4, P =0.6). Median subjective image quality scores were comparable (no-shield: 4.0, interquartile range: 3.5 to 4.4, shield: 4.3, interquartile range: 4.0 to 4.5). Combining low-dose CTPA with breast shields confers additional breast-dose savings without impacting image quality and yields breast doses approaching those of low-dose scintigraphy, suggesting breast shields play a role in protocol optimization for select groups.

778TiP A phase I/II trial investigating safety and efficacy of autologous TAC T-cells targeting HER2 in relapsed or refractory solid tumors

Despite historic and recent therapeutic developments for patients with advanced, metastatic, unresectable HER2-positive (HER2+) solid tumors, significant unmet medical needs still exist, especially in tumors other than breast and gastric cancers. The T cell antigen coupler (TAC) technology is a novel approach to modifying T cells, allowing them to recognize and treat HER2+ solid tumors. Mechanistically, the TAC receptor redirects T cells to tumor cells, and upon tumor cell recognition, co-opts the natural T cell receptor (TCR) to yield safer anti-tumor responses versus chimeric antigen receptor (CAR) T cells. In preclinical studies, TAC T cells led to complete tumor clearance in various mouse models of human cancer, without any TAC-related toxicities, and potentially superior results to T cells engineered with a 2nd-generation CAR. In the ongoing clinical trial (NCT04727151), TAC T cell treatment in HER2+ solid tumors is hypothesized to result in safe and effective anti-tumor responses, with fewer cytokine release syndrome (CRS) and neurotoxicity events. Procedurally, subjects undergo leukapheresis, bridging therapy (if needed) while their TAC T cells are engineered, lymphodepletion chemotherapy, and finally TAC T cell infusion. Phase I dose escalation is investigating TAC T cells doses of 0.08, 0.3 (starting dose), 0.8, 3, 8 x 106 cells/kg in HER2+ solid tumors (1+, 2+ or 3+ by immunohistochemistry) in adult subjects who have progressed after ≥2 lines of systemic therapy. Dose limiting toxicities (DLTs) are assessed up to 28 days from engineered cell infusion. In Phase 2, dose expansion groups will further evaluate the safety, efficacy, and pharmacokinetics of the optimal TAC T cell dose in breast, lung, pancreatic, colorectal, gastric, endometrial, ovarian, and other tumor types. As of 13 Apr 2022, 3 patients have been treated in Cohort 1 (0.3 x 106 cells/kg): rectosigmoid, gastro-esophageal, and gastric adenocarcinoma. No DLTs, CRS, or neurotoxicity events have been reported, with the Data Safety Monitoring Committee recommending commencement of patient enrollment in Cohort 2. NCT04727151. The authors.

Optimization of the exposure parameters in digital mammography for diverse glandularities using the contrast-detail metric

PurposeThis investigation aims to study the optimization in digital mammography, considering a diverse percentage of breast glandularity using the contrast-detail metric. MethodsThe Figure of Merit (FOM), defined as the ratio of the square of the Inverted Image Quality Figure (IQFINV) by the Mean Glandular Dose (MGD), was used. A Monte Carlo simulation study was carried out to calculate the Normalized Glandular Dose (DgN). A contrast detail analysis employing the test object Contrast-Detail Mammography Phantom (CDMAM, type 3.4) was performed in the Hologic digital mammography system-model Selenia located in the Research Center in Radiation Sciences and Technologies (CPqCTR) facilities (Brazil). It employed the CIRS phantom with 20 %, 30 %, 50 % of glandularity, and 6.0 cm in thickness. ResultsIt was obtained new acquisition parameters for all glandularities that achieved a decrease in the MGD up to ∼ 50 %, maintaining the same image quality. The study was validated using the CIRS, TORMAM, and ACR phantoms through the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and the MGD values obtained with the optimized parameters and the four AEC modes, which are the optimization proposed by the manufacturer. ConclusionsIn this work, a new procedure was proposed that estimated the IQFINV value using the equivalence criterion between the CIRS phantom and the CDMAM test object with their respective PMMA plates. Based on the optimization carried out in this investigation, the AEC parameters, considering diverse glandularities, could be improved. This achievement permits the implementation of new protocols that optimize the ratio between the image's quality and the breast dose with 6.0 cm in thickness and 20 %, 30 %, and 50 % glandularity using contrast-detail metric.

Dosimetric evaluation of different radiotherapy techniques in mastectomized left-sided breast cancer.

Inclusion of internal mammary lymph nodes in mastectomized left breast cancer radiotherapy may lead to high dose receiving risk of the heart, lung, and contralateral breast. The aim of this study is to compare the dosimetric differences of field-in-field (FIF), volumetric-modulated arc therapy (VMAT), seven-field intensity-modulated radiotherapy (7F-IMRT), and helical tomotherapy (HT) planning techniques for mastectomized left breast cancer. Computed tomography images of ten patients treated with the FIF technique were used to compare four different treatment planning techniques. Planning target volume (PTV) included chest wall and regional lymph nodes. The heart, left anterior descending coronary artery (LAD), left and whole lung, thyroid, esophagus, and contralateral breast were identified as organs-at-risks (OARs). Except for HT, a single isocenter in PTV and bolus of thickness 0.3 cm on the chest wall was used. Complete and directional blocks were applied in HT, and the dosimetric parameters of PTV and OARs for four different techniques were analyzed using the Kruskal-Wallis test. 7F-IMRT, VMAT, and HT were superior to the FIF technique in providing homogeneous dose distribution covering the PTV (P < 0.0001). Mean doses (Dmean) of the contralateral breast and esophagus, lung, and body-PTV V5 (volume receiving 5 Gy) were reduced in FIF, whereas in the HT, Heart Dmean, LAD Dmean , Dmax, healthy tissue (body-PTV) Dmean , heart and left lung V20, and thyroid V30 were significantly reduced (P < 0.0001). FIF and HT techniques were found to be significantly advantageous over 7F-IMRT and VMAT for OARs. Using those three multiple-beam techniques reduced high-dose volumes of healthy tissues and organs in mastectomized left breast cancer radiotherapy but also increased low-dose volumes and contralateral lung and breast doses. Complete and directional blocks applied in HT reduce heart, lung, and contralateral breast doses.

Ionizing radiation and volumetric mammographic density.

Mammographic density (MD) refers to the percentage of dense tissue of an entire breast and was proposed to be used as a surrogate marker for breast cancer. High-dose ionizing radiation (IR) has been recognized as a breast cancer risk factor. The aim of our study was to investigate association between lifetime low dose ionizing radiation (LDIR) and MD. A cross-sectional study included 467 women aged 40-60 years who underwent screening mammography in Łódź, Poland. The digital mammography examination of the breasts included both craniocaudal and mediolateral oblique views. The volumetric breast density (VBD) (%) and fibrograndular tissue volume (FG) (cm3) were determined based on the analysis of mammographic image ("for processing") using Volpara Imaging Software. The exposure to IR was estimated for each individual, based on the data from interviews about diagnostic or therapeutic medical procedures performed in the area of the neck, chest, abdomen and spine, which involved X-rays and γ rays and the data about the doses derived from literature. Linear and logistic regression were fitted with VBD and FG as the outcomes and organ breast dose, effective dose and number of mammographies as the determinants, adjusted for major confounders. The analyses showed no association between VBD or FG and the breast organ dose or the effective dose. The only significant finding observed concerned the association between the number of mammographies and the FG volume with β coefficient: 0.028 (95% CI: 0.012-0.043), and predicted mean FG volume >13.4 cm3 among the women with >3 mammographies when compared to those with none. This study does not, in general, provide support for the positive association between LDIR and MD. The weak association of the FG volume with the number of mammographies warrants further verification in larger independent studies. Int J Occup Med Environ Health. 2022;35(5):635-49.

Regression Analysis between the Different Breast Dose Quantities Reported in Digital Mammography and Patient Age, Breast Thickness, and Acquisition Parameters.

Breast cancer is the leading cause of cancer death among women worldwide. Screening mammography is considered the primary imaging modality for the early detection of breast cancer. The radiation dose from mammography increases the patients’ risk of radiation-induced cancer. The mean glandular dose (MGD), or the average glandular dose (AGD), provides an estimate of the absorbed dose of radiation by the glandular tissues of a breast. In this paper, MGD is estimated for the craniocaudal (CC) and mediolateral–oblique (MLO) views using entrance skin dose (ESD), X-ray spectrum information, patient age, breast glandularity, and breast thickness. Moreover, a regression analysis is performed to evaluate the impact of mammography acquisition parameters, age, and breast thickness on the estimated MGD and other machine-produced dose quantities, namely, ESD and organ dose (OD). Furthermore, a correlation study is conducted to evaluate the correlation between the ESD and OD, and the estimated MGD per image view. This retrospective study was applied to a dataset of 2035 mammograms corresponding to a cohort of 486 subjects with an age range of 28–86 years who underwent screening mammography examinations. Linear regression metrics were calculated to evaluate the strength of the correlations. The mean (and range) MGD for the CC view was 0.832 (0.110–3.491) mGy and for the MLO view was 0.995 (0.256–2.949) mGy. All the mammography dose quantities strongly correlated with tube exposure (mAs): ESD (R2 = 0.938 for the CC view and R2 = 0.945 for the MLO view), OD (R2 = 0.969 for the CC view and R2 = 0.983 for the MLO view), and MGD (R2 = 0.980 for the CC view and R2 = 0.972 for the MLO view). Breast thickness showed a better correlation with all the mammography dose quantities than patient age, which showed a poor correlation. Moreover, a strong correlation was found between the calculated MGD and both the ESD (R2 = 0.929 for the CC view and R2 = 0.914 for the MLO view) and OD (R2 = 0.971 for the CC view and R2 = 0.972 for the MLO view). Furthermore, it was found that the MLO scan views yield a slightly higher dose compared to CC scan views. It was also found that the glandular absorbed dose is more dependent on glandularity than size. Despite being more reflective of the dose absorbed by the glandular tissue than OD and ESD, MGD is considered labor-intensive and time-consuming to estimate.