Search Results (38)

This study systematically investigates the mechanism by which total ionizing dose (TID) affects the lifetime degradation of NMOS devices induced by hot-carrier injection (HCI). Experiments involved Cobalt-60 (Co-60) gamma-ray irradiation to a cumulative dose of 500 krad (Si), followed by 168 h annealing at 100 °C to simulate long-term stability. However, under HCI stress conditions (V_D = 2.7 V, V_G = 1.8 V), irradiated devices show a 6.93% increase in threshold voltage shift (ΔV_th) compared to non-irradiated counterparts. According to the IEC 62416 standard, the lifetime degradation of irradiated devices induced by HCI stress is only 65% of that of non-irradiated devices. Conversely, when the saturation drain current (I_Dsat) degrades by 10%, the lifetime doubles compared to non-irradiated counterparts. Mechanistic analysis demonstrates that partial neutralization of E’ center positive charges at the gate oxide interface by hot electrons weakens the electric field shielding effect, accelerating ΔV_th drift, while interface trap charges contribute minimally to degradation due to annealing-induced self-healing. The saturation drain current shift degradation primarily correlates with electron mobility variations. This work elucidates the multi-physics mechanisms through which TID impacts device reliability and provides critical insights for radiation-hardened design optimization. Full article

Purpose: We present our single-institution experience of sarcomatous brain metastasis patients who underwent stereotactic radiosurgery (SRS) over the past 35 years. Methods: In total, 31 patients (16 males) who underwent SRS for sarcoma brain metastases were identified. Median age at presentation to SRS was 47 (range: 4–78) months. Common histopathologies included leiomyosarcoma (eight patients), osteosarcoma (six patients), alveolar sarcoma (three patients), Ewing sarcoma (three patients), and undifferentiated/unclassified sarcoma (three patients). The median Karnofsky Performance Score (KPS) was 90. Nine patients underwent pre-SRS craniotomy. The median dose prescribed was 18 Gy. The median cumulative tumor volume was 1.4 cc. Results: Median patient overall survival (OS) after SRS was 7 (range: 0–155) months. Local tumor control (LTC) was achieved in 105 out of 113 tumors, at a median time of 3 (range: 0–17) months between SRS and progression. LTC rates per patient and per tumor were 74.2% and 92.9%, respectively. Following SRS, 10 patients (32.3%) developed new tumors at a median time of 6 (range: 1–25) months. Four patients experienced adverse radiation effects (AREs). At the last follow-up, all patients died, one patient from intracranial progression, 27 from systemic disease progression, and the remaining from unrelated medical conditions. Conclusions: Given high LTC and low ARE rates, this suggests SRS as a strong candidate for the non-invasive management of sarcomatous brain metastases, which typically present late following initial presentation of the primary disease. Full article

Objective: We aimed to evaluate the feasibility, added value, and radiation dose of coronary computed tomography angiography (CCTA) and stress dynamic CT myocardial perfusion imaging (MPI) in patients with coronary artery disease (CAD) in a real-world setting. Materials and Methods: This retrospective study included 65 patients (mean age: 51.2 ± 11.5 years; 21 female) with moderate CAD, selected from the Radiological Database of our hospital between May 2022 and December 2024. All patients underwent CCTA and stress dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used for CT-MPI with 60 mL of contrast (iopamidol, 370 mg iodine/mL) administered at a flow rate of 6 mL/s. The mean myocardial blood flow (MBF) and other quantitative parameters were measured for both CAD and reference segments (RSs). A 17-segment-based analysis was employed (excluding the apex). The MBF ratio, defined as the mean MBF value of CAD segments divided by that of RS, was used with a cut-off value of 0.85 to distinguish hypoperfused from non-hypoperfused segments within CAD territories. Non-parametric statistical tests were applied. Results: A total of 1040 segments were evaluated. In 62 segments, the mean MBF of CAD territories was found to have decreased. The mean MBF and myocardial blood volume (MBV) in hypoperfused CAD segments were 65.1 ± 19.8 mL/100 mL/min and 14.5 ± 2.7 mL/100 mL, respectively, both significantly lower compared to non-hypoperfused CAD segments and RSs (p < 0.001). The mean effective dose of the protocol was 6.3 ± 1.4 mSv, corresponding to an estimated individual lifetime cancer risk of approximately 0.06% per test, based on BEIR VII Phase 2 modeling. This risk is cumulative, with repeat testing over a 10-year period potentially increasing lifetime cancer risk in proportion to total radiation exposure. The mean total examination time was 26 ± 4 min. Conclusion: The combined CCTA and dynamic CT-MPI protocol is feasible in real-world clinical practice and offers a comprehensive morphological and functional assessment of moderate CAD, with a manageable radiation dose and examination time. Full article

Introduction: Percutaneous cryoablation (PCA) can be a valid alternative to partial nephrectomy for patients with cT1a renal tumors. A potential disadvantage of PCA is radiation exposure for patients, though the exact significance of this is unknown. This study aims to uncover the degree of radiation exposure during PCA and what factors are of influence. Methods: This is a retrospective analysis of a prospectively maintained database of patients who underwent CT-guided PCA for cT1 renal cell carcinoma (RCC) between January 2014 and September 2024. The median effective dose (mSV) of PCA was calculated and compared to the expected cumulative radiation exposure during follow-up. Multivariate linear regression was performed to identify factors predictive of higher radiation exposure (mSV). Results: A total of 164 PCAs were performed, with radiation data available for 133 cases. Mean age was 65 (±11) years and the mean tumor diameter was 28 (±9.6) mm. Median effective dose of the CA procedures was 26 mSV (IQR 18–37). The estimated cumulative effective dose of follow-up CT scans according to 2016 and 2024 European Association of Urology guidelines was 158 (IQR 117–213) and 105 mSV (IQR 78–142), respectively. Multivariate linear regression analysis identified BMI (OR 1.723, p < 0.001), the number of needles used (OR 4.060, p < 0.001), and the necessity for additional procedures (OR 8.056, p < 0.001) as significant predictors of a higher effective dose. Conclusions: We found a median effective dose of 26 mSV for PCA, which is relatively low compared to the cumulative radiation exposure associated with CT scans during follow-up of patients post-ablation according to the guidelines. Furthermore, increased BMI, a higher number of required needles and the execution of additional procedures are all associated with a higher effective dose. Full article

(1) Background: The management of ipsilateral breast cancer recurrence depends on the extent of the tumor, and staging results, and mastectomy is currently the standard of care for previously irradiated patients. Studies are increasingly investigating suitable candidates for the repeated use of breast-conserving approaches as an alternative to mastectomy. But this includes the crucial necessity for curative reirradiation (Re-RT). The therapeutic challenge in reirradiation involves finding a balance between tumor control and the risk of severe toxicity from cumulative radiation doses in previously irradiated organs. Re-RT options include the use of brachytherapy, intraoperative radiotherapy, or external beam RT with photons or electrons. The application of particle therapy using proton beam therapy represents an innovative radiotherapeutic technique for breast cancer patients that might offer advantageous physical properties, a superior dose reduction to adjacent organs-at-risk, and effective target volume coverage with lower integral doses to the patient’s whole body. In addition, this technique could potentially offer higher radiobiological effects and tumor responses. (2) Methods: The BREAST trial (NCT06954623) will be conducted as a prospective, single-arm, phase II study in 20 patients with histologically proven invasive breast cancer recurrences after repeat breast-conserving surgery and with an indication for local reirradiation. The patients will receive partial-breast re-RT with proton beam therapy in 15 once-daily fractions up to a total dose of 40.05 Gy(RBE), delivered with active raster scanning. The required time interval will be 1 year after previous RT to the ipsilateral breast. (3) Results: The following results will be reported: The primary endpoint is defined as the cumulative overall occurrence of (sub)acute skin toxicity of grade ≥ 3 within 6 months after the start of re-RT. Secondary outcome includes an analysis of the local, regional, and distant control, progression-free and overall survival, quality of life, and cosmesis. The explorative and translational objectives of this study include planning comparisons to other RT techniques and irradiation types, dosimetric evaluations, analyses of radiological imaging features, and translational assessments of cardiac toxicity biomarkers and tumor markers. (4) Conclusions: Overall, the aim of this study is to evaluate the potential of proton beam therapy for partial breast reirradiation and to establish the underlying data for a randomized trial. Full article

Purpose: To evaluate the variability of oncogenic risk related to radiation exposure in patients frequently exposed to ionizing radiation for diagnostic purposes, specifically ICU patients, according to different risk models, including the BEIR VII, ICRP 103, and US EPA models. Methods: This was an IRB-approved observational retrospective study. A total of 71 patients (58 male, 13 female; median age, 66 years; interquartile range [IQR], 65–71 years) admitted to the ICU who underwent X-ray examinations between 1 October 2021 and 28 February 2023 were included. For each patient, the cumulative effective dose during a single hospital admission was calculated. Lifetime attributable risk (LAR) was estimated based on the BEIR VII, ICRP 103, and US EPA risk models to calculate additional oncogenic risk related to radiation exposure. The Friedman test for repeated-measures analysis of variance was used to compare risk values between different models. The intraclass correlation coefficient (ICC) was used to assess the consistency of risk values between different models. Results: Different organ, leukemia, and all-cancer risk values estimated according to different oncogenic risk models were significantly different, but the intraclass correlation coefficient revealed a good (>0.75) or even excellent (>0.9) agreement between different risk models. The ICRP 103 model estimated a lower all-cancer (median 69.05 [IQR 30.35–195.37]) and leukemia risk (8.22 [3.02–27.93]) compared to the US EPA (all-cancer: 139.68 [50.51–416.16]; leukemia: 23.34 [3.47–64.37]) and BEIR VII (all-cancer: 162.08 [70.6–371.40]; leukemia: 24.66 [12.9–58.8]) models. Conclusions: Cancer risk values were significantly different between risk models, though inter-model agreement in the consistency of risk values was found to be good, or even excellent. Full article

Background: Blunt carotid injury (BCI) in pediatric trauma is quite rare. Due to the low number of cases, only a few reports and studies have been conducted on this topic. This review will discuss how frequent BCI/blunt cerebrovascular injury (BCVI) on pediatric patients after blunt trauma is, what routine diagnostics looks like, if a computed tomography (CT)/computed tomography angiography (CTA) scan on pediatric patients after blunt trauma is always necessary and if there are any negative health effects. Methods: This narrative literature review includes reviews, systematic reviews, case reports and original studies in the English language between 1999 and 2020 that deal with pediatric blunt trauma and the diagnostics of BCI and BCVI. Furthermore, publications on the risk of radiation exposure for children were included in this study. For literature research, Medline (PubMed) and the Cochrane library were used. Results: Pediatric BCI/BCVI shows an overall incidence between 0.03 and 0.5% of confirmed BCI/BCVI cases due to pediatric blunt trauma. In total, 1.1–3.5% of pediatric blunt trauma patients underwent CTA to detect BCI/BCVI. Only 0.17–1.2% of all CTA scans show a positive diagnosis for BCI/BCVI. In children, the median volume CT dose index on a non-contrast head CT is 33 milligrays (mGy), whereas a computed tomography angiography needs at least 138 mGy. A cumulative dose of about 50 mGy almost triples the risk of leukemia, and a cumulative dose of about 60 mGy triples the risk of brain cancer. Conclusions: Given that a BCI/BCVI could have extensive neurological consequences for children, it is necessary to evaluate routine pediatric diagnostics after blunt trauma. CT and CTA are mostly used in routine BCI/BCVI diagnostics. However, since radiation exposure in children should be as low as reasonably achievable, it should be asked if other diagnostic methods could be used to identify risk groups. Trauma guidelines and clinical scores like the McGovern score are established BCI/BCVI screening options, as well as duplex ultrasound. Full article

Introduction: The rate of isolated locoregional recurrence after surgery for pancreatic adenocarcinoma (PDAC) approaches 25%. Ablative radiation therapy (A-RT) has improved outcomes for locally advanced disease in the primary setting. We sought to evaluate the outcomes of salvage A-RT for isolated locoregional recurrence and examine the relationship between subsequent patterns of failure, radiation dose, and treatment volume. Methods: We conducted a retrospective analysis of all consecutive participants who underwent A-RT for an isolated locoregional recurrence of PDAC after prior surgery at our institution between 2016 and 2021. Treatment consisted of ablative dose (BED10 98–100 Gy) to the gross disease with an additional prophylactic low dose (BED10 < 50 Gy), with the elective volume covering a 1.5 cm isotropic expansion around the gross disease and the circumference of the involved vessels. Local and locoregional failure (LF and LRF, respectively) estimated by the cumulative incidence function with competing risks, distant metastasis-free and overall survival (DMFS and OS, respectively) estimated by the Kaplan–Meier method, and toxicities scored by CTCAE v5.0 are reported. Location of recurrence was mapped to the dose region on the initial radiation plan. Results: Among 65 participants (of whom two had two A-RT courses), the median age was 67 (range 37–87) years, 36 (55%) were male, and 53 (82%) had undergone pancreaticoduodenectomy with a median disease-free interval to locoregional recurrence of 16 (range, 6–71) months. Twenty-seven participants (42%) received chemotherapy prior to A-RT. With a median follow-up of 35 months (95%CI, 26–56 months) from diagnosis of recurrence, 24-month OS and DMFS were 57% (95%CI, 46–72%) and 22% (95%CI, 14–37%), respectively, while 24-month cumulative incidence of in-field LF and total LRF were 28% (95%CI, 17–40%) and 36% (95%CI 24–48%), respectively. First failure after A-RT was distant in 35 patients (53.8%), locoregional in 12 patients (18.5%), and synchronous distant and locoregional in 10 patients (15.4%). Most locoregional failures occurred in elective low-dose volumes. Acute and chronic grade 3–4 toxicities were noted in 1 (1.5%) and 5 patients (7.5%), respectively. Conclusions: Salvage A-RT achieves favorable OS and local control outcomes in participants with an isolated locoregional recurrence of PDAC after surgical resection. Consideration should be given to extending high-dose fields to include adjacent segments of at-risk vessels beyond direct contact with the gross disease. Full article

Background: The role of stereotactic radiosurgery (SRS) for patients with brain metastases from hepatopancreaticobiliary (HPB) cancers has yet to be established. The authors present a single-institution experience of patients with HPB cancers who underwent SRS when their cancer spread to the brain. Methods: We surveyed our Gamma Knife SRS data base of 18,000 patients for the years 1987–2022. In total, 19 metastatic HPB cancer patients (13 male) with 76 brain metastases were identified. The median age at SRS was 61 years (range: 48–83). The primary cancer sites were hepatocellular carcinoma (HCC, 11 patients), cholangiocarcinoma (CCC, 2 patients), and pancreatic carcinoma (PCC, 6 patients). The median Karnofsky Performance Score (KPS) was 80 (range: 50–90). Two patients underwent pre-SRS whole-brain fractionated radiation therapy (WBRT) and eight patients underwent pre-SRS surgical resection. All SRS was delivered in single session. The median margin dose was 18 Gy (range: 15–20). The median cumulative tumor volume was 8.1 cc (range: 1.0–44.2). Results: The median patient overall survival (OS) after SRS was 7 months (range 1–79 months). Four patients had documented local tumor progression after SRS at a median time of 8.5 months (range: 2–15) between SRS and progression. Out of 76 treated tumors, 72 tumors exhibited local control. The local tumor control rate per patient was 78.9%. The local tumor control per tumor was 94.7%. Four patients developed new brain metastases at a median of 6.5 months (range: 2–17) after SRS. No patient experienced adverse radiation effects (AREs). At the last follow-up, 18 patients had died, all from systemic disease progression. Conclusions: Metastatic spread to the brain from HPB cancers occurs late in the course of the primary disease. In this study, all deceased patients ultimately died from primary disease progression. SRS is a non-invasive strategy that maximally preserves quality of life, and our results reported favorable outcomes compared to the existing literature. SRS should be considered as one of the primary management strategies for patients with brain metastatic spread from HPB cancer. Full article

(1) Background: The prevalence of cancer patients relying on cardiac implantable electronic device (CIED) is steadily rising. The aim of this study was to evaluate RT-related malfunctions of CIEDs. (2) Methods: We retrospectively analyze sixteen patients with esophageal cancer who were treated with radiotherapy between 2012 and 2022 at the University Hospital Heidelberg. All patients underwent systemic evaluation including pre-therapeutic cardiological examinations of the CIED functionality and after every single irradiation. (3) Results: Sixteen patients, predominantly male (14) with a mean age of 77 (range: 56–85) years were enrolled. All patients received 28 fractions of radiotherapy with a cumulative total dose 58.8 Gy. The mean maximum dose at the CIEDs was 1.8 Gy. Following radiotherapy and during the one-year post-radiation follow-up period, there were no registered events associated with the treatment in this evaluation. (4) Conclusion: The study did not observe any severe CIED malfunctions following each radiation fraction or after completion of RT. Strict selection of photon energy and alignment with manufacturer-recommended dose limits appear to be important. Our study showed no major differences in the measured values of the pacing threshold, sensing threshold and lead impedance after RT. Full article

Background: Neuroendocrine tumors (NET) are neoplasms that secrete peptides and neuroamines. For gastroenteropancreatic (GEP) NET, surgical resection represents the only curative option. Ten-year imaging surveillance programs are recommended due to long time-to-recurrence following resection. We performed retrospective chart review evaluating radiation exposure and practice patterns from surveillance of completely resected GEP NET. Methods: We performed a retrospective cohort study of cases with well-differentiated GEP NET from January 2005 to July 2020. Location of primary, modality of imaging, and duration of follow-up were collected. Dosimetry data was collected to calculate effective dose. Results: 62 cases were included with 422 surveillance scans performed. Cross-sectional imaging was used in 82% and functional imaging was used in 18% of scans. Mean number of scans per year was 1.25 (0.42–3). Mean total effective dose was 56.05 mSv (SD 45.56; 0 to 198 mSv) while mean total effective dose per year was 10.62 mSv (SD 9.35; 0 to 45 mSv). Over the recommended ten years of surveillance the estimated total effective dose was 106 mSv. Conclusions: Surveillance of completely resected GEP NET results in cumulative radiation doses in the range associated with secondary malignancy development. Strategies to minimize radiation exposure in surveillance should be considered in future guideline development. Full article

Irradiation with electrons is the primary treatment regime for localized conjunctival low-grade lymphomas. However, radiation-induced cataracts are a major cause of treatment-related morbidity. This study investigates whether lens-sparing electron irradiation produces sufficient disease control rates while preventing cataract formation. All consecutive patients with strictly conjunctival, low-grade Ann Arbor stage IE lymphoma treated with superficial electron irradiation between 1999 and 2021 at our department were reviewed. A total of 56 patients with 65 treated eyes were enrolled with a median follow-up of 65 months. The median dose was 30.96 Gy. A lens-spearing technique featuring a hanging rod blocking the central beam axis was used in 89.2% of all cases. Cumulative incidences of 5- and 10-year infield recurrences were 4.3% and 14.6%, incidences of 5- and 10-year outfield progression were 10.4% and 13.4%. We used patients with involvement of retroorbital structures treated with whole-orbit photon irradiation without lens protection—of which we reported in a previous study—as a control group. The cumulative cataract incidence for patients treated with electrons and lens protection was significantly lower (p = 0.005) when compared to patients irradiated without lens protection. Thus, electrons are an effective treatment option for conjunctival low-grade lymphomas. The presented lens-sparing technique effectively prevents cataract formation. Full article

Purpose: This study analyses a large number of cancer patients with CIEDs for device malfunction and premature battery depletion by device interrogation after each radiotherapy fraction and compares different guidelines in regard to patient safety. Methods: From 2007 to 2022, a cohort of 255 patients was analyzed for CIED malfunctions via immediate device interrogation after every RT fraction. Results: Out of 324 series of radiotherapy treatments, with a total number of 5742 CIED interrogations, nine device malfunctions (2.8%) occurred. Switching into back-up/safety mode and software errors occurred four times each. Once, automatic read-out could not be performed. The median prescribed cumulative dose at planning target volume (PTV) associated with CIED malfunction was 45.0 Gy (IQR 36.0–64.0 Gy), with a median dose per fraction of 2.31 Gy (IQR 2.0–3.0 Gy). The median maximum dose at the CIED at time of malfunction was 0.3 Gy (IQR 0.0–1.3 Gy). No correlation between CIED malfunction and maximum photon energy (p = 0.07), maximum dose at the CIED (p = 0.59) nor treatment localization (p = 0.41) could be detected. After excluding the nine malfunctions, premature battery depletion was only observed three times (1.2%). Depending on the national guidelines, 1–9 CIED malfunctions in this study would have been detected on the day of occurrence and in none of the cases would patient safety have been compromised. Conclusion: Radiation-induced malfunctions of CIEDs and premature battery depletion are rare. If recommendations of national safety guidelines are followed, only a portion of the malfunctions would be detected directly after occurrence. Nevertheless, patient safety would not be compromised. Full article

The radiation effect of materials is very important and directly related to the safety and reliability of nuclear reactors. Polymer materials, one of the indispensable materials in nuclear power equipment, must withstand the ordeal of high-energy ionizing rays. In this work, through screening different γ-ray dose irradiation conditions, we systematically and comprehensively study the changes in the structure and properties of nitrile butadiene rubber (NBR) before and after γ-ray static irradiation at a high dose rate, and master the rule and mechanism of the γ-ray static irradiation effect of these polymer materials. The mapping relationship between the macroscopic properties, microstructure, and irradiation dose of NBR is accurately characterized. With an increase in total irradiation dose, the C=C double bond reaction occurs, and the C≡N bond, C=C, and C=O participate in the hyper crosslinking reaction. The glass transition temperature (T_g) increases with the cumulative irradiation amount. With the increased total irradiation amount, the degree of rubber cross-linking increases, causing an increased crystallinity and decomposition temperature. A growing amount of gamma irradiation causes the mechanical properties of the rubber to degrade simultaneously, increasing the shore hardness while decreasing the tensile strength and ultimate elongation at break. When the cumulative amount reaches 1 MGy, the ultimate elongation at break decreases significantly. A cumulative dose of radiation resistance of 4 MGy can be achieved by the samples. This work can provide theoretical and experimental support for the long-term stability of nitrile butadiene rubber and its derivatives in nuclear radiation fields and space radiation conditions. Full article

This study designed a radiation-hardened (RH) complementary metal oxide semiconductor (CMOS) logic circuit based on an RH variable-gate (V-gate) n-MOSFET that was resistant to the total ionizing dose (TID) effect and evaluated its tolerance to radiation. Among the different CMOS logic circuits, NOT, NAND, and NOR gates were designed using V-gate n-MOSFETs by employing layout transformation techniques and standard p-MOSFETs. Before the process design, we predicted the radiation damage using modeling and simulation techniques and validated the tolerance by conducting actual radiation tests after the process design. Furthermore, we implemented the CMOS logic circuit process design in a 0.18 µm CMOS bulk process. The actual radiation test applied a total cumulative radiation dose of 25 kGy at 5 kGy per hour in a high-level gamma-ray irradiation facility. Consequently, the resistance of the RH CMOS logic circuit based on the RH V-gate n-MOSFET to the TID effect was validated through experiments. Full article