Radiation Dose Research Articles

Evaluating the Efficacy of Deep Learning Reconstruction in Reducing Radiation Dose for Computer-Aided Volumetry for Liver Tumor: A Phantom Study.

The purpose of this study was to compare radiation dose reduction capability for accurate liver tumor measurements of a computer-aided volumetry (CADv) software for filtered back projection (FBP), hybrid-type iterative reconstruction (IR), mode-based iterative reconstruction (MBIR), and deep learning reconstruction (DLR) at a phantom study. A commercially available anthropomorphic abdominal phantom was scanned five times with a 320-detector row CT at 600 mA, 400 mA, 200 mA, and 100 mA and reconstructed by four methods. Signal-to-noise ratios (SNRs) of all lesions within the arterial and portal-venous phase inserts were calculated, and SNR of the lesion phantom was compared with that of all reconstruction methods by means of Tukey's honestly significant difference (HSD) test. Then, tumor volume (V) of each nodule was automatically measured using commercially available CADv software. To compare dose reduction capability for each reconstruction method at both phases, mean differences between measured V and standard references were compared by Tukey's honestly significant difference test among the four different reconstruction methods on CT obtained at each of the four tube currents. With each of the tube currents, SNRs for MBIR and DLR were significantly higher than those for FBP and hybrid-type IR (p < 0.05). At the arterial phase, the mean difference in V for the CT protocol obtained at 600 or 100 mA and reconstructed with DLR was significantly smaller than that for others (p < 0.05). At the portal-venous phase, the mean differences in V for the CT protocol obtained at 100 mA and reconstructed with hybrid-type IR, MBIR, and DLR were significantly smaller than that for FBP (p < 0.05). Findings of our phantom study show that reconstruction method had influence on CADv merits for abdominal CT with not only standard but also reduced dose examinations and that DLR can potentially yield better image quality and CADv measurements than FBP, hybrid-type IR, or MBIR in this setting.

The head of invasive cardiologists as a target of professional exposure to ionizing radiation

Exposure to ionizing radiation has recognized detrimental cancer and non-cancer health effects. These effects are now well-proven not only for high doses &gt; 1,000 millisieverts (mSv) associated with head radiotherapy but also for moderate (100–1,000 mSv) and even low (&lt; 100 mSv) doses, of interest for professionally exposed cardiologists. The head of interventional cardiologists is highly exposed to ionizing radiation, with possible damage to the eye and brain. Unprotected interventional cardiologists experience head radiation doses up to ten times greater than chest doses below lead aprons, with marked exposure to the left hemisphere of the brain reaching up to 2 Sv—equivalent to 10,000 chest X-rays over a professional lifetime. This narrative review aims to provide an overview of the background of radioprotection, the biological mechanisms involved, and the epidemiological evidence regarding the health effects of head exposure to ionizing radiation in invasive cardiologists. These health effects include cataracts, brain cancer, cerebrovascular diseases, neurodegeneration, and mood disorders. The evidence gathered from other exposed populations, which experienced similar eye and brain doses, has also been reviewed. This is important because the doses, risks, and effects are consistent in cases of repeated exposures, which occur more frequently for patients, and in situations involving chronic low doses, as seen with interventional cardiologists. Despite these risks, effective protective measures—such as suspended lead ceilings, curtains, and specialized eyewear—can reduce radiation exposure to near-zero levels. In some fields, like interventional cardiac electrophysiology, a groundbreaking near-zero radiation approach using non-fluoroscopic methods has been created, eliminating radiation exposure and alleviating orthopedic stress and operational discomfort. The race to zero radiation in interventional cardiology is ongoing.

Influence of electron radiation of spring barley seeds on phytopathogenic microflora

Under the conditions of a model pot experiment, the effect of electron irradiation on the phytopathogenic microflora of plant roots and leaves was studied. The studies were carried out on spring barley seeds of the Vladimir variety (reproduction 1), affected by helminthosporiosis (pathogen Bipolaris sorokiniana Shoem.), (natural infectious background). This pathogen causes root rot and leaf spot. The grain was irradiated using a wide-aperture electron accelerator “Duet” with a mesh plasma cathode and the output of the generated beam of a large cross-section into the atmosphere in doses of 1, 2, 3, 4 and 5 kGy. The total administered dose was increased by changing the number of pulses. The radiation dose rate was 100 Gy/pulse, the electron energy was 130 keV (mode 1) and 160 keV (mode 2). The depth of dose absorption did not exceed 300 μm. Based on the conducted studies on the effect of electron irradiation on root rot (pathogen Bipolaris sorokiniana) of spring barley, it was noted that in the tillering and heading phases, when irradiating seed material with a dose of 2 kGy in mode 1 (130 keV), the disease incidence and prevalence decreased by more than 1.5 times compared to the non-irradiated control. In the phase of full grain maturity, the highest value of root infestation (45–50%) and prevalence (95–100%) of Bipolaris sorokiniana were recorded, but statistically significant differences between the irradiated variants and the control were absent. The records of the damage of vegetative plants showed that in the tillering phase, for all irradiation variants in mode 1, the degree of damage to leaves 1–3 increased by 23% compared to the control, and in the heading phase, the degree of damage to the upper leaves (1–3) exceeded the control when irradiated at doses of 2–5 kGy (mode 1) and 1–5 kGy (mode 2) – 2.1–2.8 times for 1 leaf, 1.9–2.0 times for 2 leaves and 1.2 times for 3 leaves.

Radiosurgery-induced early changes in peritumoral tissue sodium concentration of brain metastases.

Stereotactic radiosurgery (SRS) is an effective therapy for brain metastases. Response is assessed with serial 1H magnetic resonance imaging (MRI). Early markers for response are desirable to allow for individualized treatment adaption. Previous studies indicated that radiotherapy might have impact on tissue sodium concentration. Thus, 23Na MRI could provide early quantification of response to SRS. We investigated whether longitudinal detection of tissue sodium concentration alteration within brain metastases and their peritumoral tissue after SRS with 23Na MRI was feasible. Prospective. Twelve patients with a total of 14 brain metastases from various primary tumors. 23Na MRI scans were acquired from patients 2 days before, 5 days after, and 40 days after SRS. Gross tumor volume (GTV) and healthy-appearing regions were manually segmented on the MPRAGE obtained 2 days before SRS, onto which all 23Na MR images were coregistered. Radiation isodose areas within the peritumoral tissue were calculated with the radiation planning system. Tissue sodium concentration before and after SRS within GTV, peritumoral tissue, and healthy-appearing regions as well as the routine follow-up with serial MRI were evaluated. Results were compared using Student's t-test and correlation was evaluated with Pearson's correlation coefficient. We found a positive correlation between the tissue sodium concentration within the peritumoral tissue and radiation dosage. Two patients showed local progression and a differing tissue sodium concentration evolution within GTV and the peritumoral tissue compared to mean tissue sodium concentration of the other patients. No significant tissue sodium concentration changes were observed within healthy-appearing regions. Tissue sodium concentration assessment within brain metastases and peritumoral tissue after SRS with 23Na MRI is feasible and might be able to quantify tissue response to radiation.

Left radial vs right femoral: comparison between arterial accesses in c-TACE procedures in terms of operator radiations exposure and patient comfort.

This multicenter prospective study aims to compare transradial access versus transfemoral access in conventional transarterial chemoembolization (c-TACE) procedures, focusing on operators radiations exposure, patients comfort, technical success and vascular access complications. Patients were affected by hepatocellularcarcinoma (HCC) in intermediate stage or previous stages unfit for ablation and/or surgery; they were randomized into two groups according to arterial access site (Group F: right femoral access in standard position; Group R: radial access with left arm abduced 90°). Overall fluoroscopy time was recorded. Eight thermoluminescence dosimeters were positioned immediately before each procedure to monitor radiation doses. Technical success was intended as complete HCC nodules lipiodolization at final plain cone-beam CT. Group F included 23 patients, while group R 19. Mean fluoroscopy time was lower in group F but difference was not statistically significant (p-value > 0.05). In terms of operators radiations exposure, no significant differences were found (p-value > 0.05). Technical success was obtained in 81.5% in group F and 84.8% in group R, without significant differences (p-value > 0.05). Patients discomfort was significantly (p-value < 0.05) higher in group F. Concerning minor complications, no statistical differences were appreciated (p-value > 0.05); no major complications occurred. In this study, no statistical differences were observed in terms of operators radiations exposure, fluoroscopy time and technical success during c-TACE performed with left radial access compared to right femoral access; patients comfort was significantly better with radial access. These data should lead interventional radiologists to favor radial access in c-TACE interventions.

Experience of rescue therapy with [177Lu]Lu-rhPSMA-10.1 in patients with primary or acquired resistance to [177Lu]Lu-PSMA-I&T.

Radioligand therapy is an increasingly important option for the treatment of metastatic castrate-resistant prostate cancer (mCRPC). Radiohybrid ligands targeting prostate-specific membrane antigen (PSMA) are a novel group of theranostic radioligand therapy agents for which higher tumour absorbed radiation doses have been demonstrated compared to established PSMA ligands. Here, we report data from ten patients who were treated within a compassionate use program with the radiohybrid PSMA-ligand [177Lu]Lu-rhPSMA-10.1 after experiencing disease progression under treatment with [177Lu]Lu-PSMA-I&T. Ten patients with advanced PSMA-positive prostate cancer who showed progression under treatment with [177Lu]Lu-PSMA-I&T received up to three cycles of rescue therapy with [177Lu]Lu-rhPSMA-10.1 (7.4-8.1 GBq per cycle). Efficacy (PSA response according to PCWG3 and RECIP) and overall survival were evaluated. Adverse events were recorded from first application. Despite progression with [177Lu]Lu-PSMA-I&T, after the first cycle of [177Lu]Lu-rhPSMA-10.1 rescue therapy, five patients (50%) showed a decrease in serum PSA level. In imaging, three of the ten patients (30%) showed a partial radiologic response. Four of the five patients with a decrease of serum PSA under [177Lu]Lu-rhPSMA-10.1 had initially responded to treatment with [177Lu]Lu-PSMA-I&T but had become resistant. However, the remaining patient had shown continuous disease progression during [177Lu]Lu-PSMA-I&T therapy but showed an immediate response to [177Lu]Lu-rhPSMA-10.1. The additional treatment with [177Lu]Lu-rhPSMA-10.1 was generally well tolerated by all patients. Patients showing tumour progression while receiving [177Lu]Lu-PSMA-I&T radioligand therapy may benefit from rescue therapy with the novel radiohybrid PSMA ligand, [177Lu]Lu-rhPSMA-10.1. Higher tumour absorbed radiation doses with [177Lu]Lu-rhPSMA-10.1 may overcome primary and acquired radiation resistance.

Metodología para la validación de programas de cálculo de dosis en piel

Objective. A methodology for facilitating the validation of skin dose estimation programs for interventional procedures is presented. Materials and methods. The methodology uses a series of irradiations stored as DICOM Radiation Dose Structured Reports (RDSRs) as well as reference skin dose values measured in each irradiation. Users must input the RDSRs to their program and compare output doses with reference doses. The authors performed 27 irradiations using two C-arms from different manufacturers. For each irradiation, the authors modified parameters that affect skin dose and measured it with an ionization chamber placed under a water phantom. The methodology was applied to validate the program SkinDose 2D. Results. Experimental measurements have an uncertainty of 13% (k=2). SkinDose 2D dose predictions differ from measurements in -9% to +8%, within experimental uncertainty. Conclusions. Varying different parameters that affect skin dose, this methodology allows for an initial validation of skin dose programs, characterizing them before any other additional measurement done by the user.

The Effects of Proton and Photon Radiation Therapy on the Development of Pediatric Dermatitis

Although radiation therapy is the leading option for effective cancer treatment, a prevalent side effect associated with it is dermatitis. Despite some available literature on this topic, there remain many gaps that need to be addressed. The goal of this study is to determine the incidence of radiation-induced dermatitis (RID) among children receiving proton and photon therapies; a retrospective chart review, at a single institution, was conducted on oncology patients who underwent proton or photon therapy radiation between 2018 and 2023. Significant differences were found between the Radiation Therapy Oncology Group (RTOG) score and the total radiation dose (p = 0.04). The median total dose of radiation received by those with an RTOG score of l was 5040.0 mGy and increased to 7600 mGy for those with a score of 3. A significant association was found between those who received chemotherapy and dermatitis (p = 0.04). No significance was found between the incidence of dermatitis in photon and proton therapy (p = 1.00). The study showed that multiple factors, including total radiation dose and chemotherapy, can affect RID. These relationships can be used to determine the modality, dose, and additional treatment options best suited to treat cancer patients in the pediatric population.

Cribriform Pattern Is a Predictive Factor of PSA Recurrence in Patients Receiving Radiotherapy After Prostatectomy.

In prostate cancer, robotic total prostatectomy is a popular treatment modality. However, prostate-specific antigen (PSA) recurrence after prostate cancer surgery remains a concern. Salvage radiotherapy is commonly used to treat PSA recurrence, but the recurrence rate after salvage radiotherapy is high, highlighting the need for better predictive markers. This study aimed to retrospectively evaluate the association between cribriform pattern and PSA recurrence in patients receiving radiotherapy after radical prostatectomy. Data of 50 patients who underwent radiotherapy after total prostatectomy between January 2010 and May 2020 were retrospectively evaluated. The median age was 67 years. Among these patients, two cases involved postoperative irradiation, while 48 cases involved salvage irradiation after postoperative PSA recurrence. The median time from surgery to PSA recurrence was 38.3 months. The median radiation dose was 64 Gy in 32 fractions. Three-dimensional conformal radiation therapy was administered in 38 cases and intensity-modulated radiation therapy was used in 12 cases. Combined hormone therapy was administered in 21 cases. PSA levels were measured every 3 months after treatment. Statistical analysis between groups was performed by a t-test. The median follow-up period after radiotherapy was 31 months. No local recurrences were observed at the prostate bed, and no deaths related to prostate cancer were recorded during follow-up. However, 18 patients (36.0%) had PSA recurrence. The PSA recurrence rate based on the cribriform pattern was 17.6% in the none to moderate group (34 patients) and 75.0% in the severe cribriform pattern group (16 patients). The PSA recurrence rate was significantly higher in patients with a severe invasive cribriform pattern (p=0.001). No significant differences were observed in other histopathological characteristics. The cribriform pattern in surgical pathology specimens was found to be a useful predictor of PSA recurrence after postoperative radiotherapy.

3D-printed brachytherapy in patients with cervical cancer: improving efficacy and safety outcomes

ObjectiveThis study aims to evaluate the efficacy and safety of 3D printing technology in brachytherapy for cervical cancer, comparing its outcomes with conventional free hand implantation brachytherapy.MethodsA total of 50 cervical cancer patients treated at the First Affiliated Hospital of Gannan Medical College from January 2019 to July 2023 were included in this study. Patients were divided into two groups: 25 patients received intensity-modulated radiotherapy (IMRT) combined with 3D-printed brachytherapy, and 25 patients underwent IMRT combined with free hand brachytherapy implantation. Key indicators analyzed included short-term therapeutic effects, survival outcomes, operation times, the number of CT scans, the number of needles inserted, dosimetric parameters, and complications.ResultsThe use of 3D-printed brachytherapy significantly improved the safety of radiation therapy operations, especially for large tumors (≥ 30 mm), by providing more precise dose distribution and reducing the radiation doses received by critical organs such as the bladder and rectum. Compared to the artificial implant group (88% prevalence), the 3D-printed brachytherapy group showed a significantly lower incidence of radiation enteritis (29.2% prevalence, p < 0.001). There were no significant differences in other complications between the two groups. For instance, the incidence of radiation cystitis was relatively high in the 3D-printed brachytherapy group (79.2% prevalence) compared to the artificial implant group (64% prevalence, p = 0.240). The median follow-up period in this study was 22.5 months [IQR 18–29]. Among the 49 patients included, 43 had cervical squamous carcinoma and 6 had cervical adenocarcinoma. Short-term therapeutic response rates were comparable, with no significant difference in overall survival observed between the two groups.Conclusion3D-printed brachytherapy offers a more effective and safer therapeutic option for patients with cervical cancer, particularly for those with large tumors or complex anatomical structures.

Feasibility of balloon rectal spacer implantation in HDR and LDR brachytherapy for prostate cancer treatment

PurposeThis study evaluates the use of a biodegradable balloon rectal spacer in two prostate cancer patients undergoing Low Dose Radiation (LDR) and salvage High Dose Radiation (HDR) brachytherapy. The spacer aims to reduce radiation dose to adjacent organs, particularly the rectum, in patients previously treated with radiation. MethodsThe balloon spacer was implanted transperineally under transrectal ultrasonography (TRUS) guidance in two patients. For the LDR case (73-year-old, intermediate-risk), the balloon was placed post-implant with 55 iodine-125 seeds delivering 145 Gy. For the HDR case (66-year-old, high-risk), the balloon was placed one week before treatment, which delivered 23 Gy in two weekly fractions using 16 channels. ResultsThe balloon provided a 14-15mm separation between rectum and prostate. In the LDR case, prostate D90 was 149.1Gy (102.83%), V100 was 91.95%, and rectum D30 was 23.93Gy (16.50%). For the HDR case, prostate D90 was 11.63Gy (105.79%), V100 was 93.63%, and rectum D0.5cc was 8.04Gy (73.15%). Both patients tolerated the treatment well, with no observed postoperative complications at 6-month follow-up. ConclusionsThe use of a rectal balloon spacer in both salvage HDR and LDR brachytherapy is feasible and safe, allowing for controlled placement and providing rectal protection from high radiation doses.

CT surveillance for type 1 autoimmune pancreatitis: cumulative radiation dose and diagnostic performance for disease relapse.

Long-term follow-up is essential for type 1 autoimmune pancreatitis (AIP) patients due to high relapse rates. The cumulative radiation dose from repeated CT scans during follow-up should not be ignored. We aim to investigate the cumulative radiation dose in AIP patients undergoing CT surveillance and the diagnostic performance of CT in detecting disease relapse. The diagnostic performance of MRI from a secondary cohort during the same period was also investigated. This retrospective single-institutional study included 247 type 1 AIP patients with one or more follow-up CT scans, and 120 patients with MR follow-ups. Four metrics were utilized to report the radiation dose, including the volume computed tomography dose index, the dose length product, size-specific dose estimate and effective dose. The diagnostic performance for AIP relapse was assessed, taking the final clinical diagnosis in retrospect as the reference standard. With a median 2.3-year follow-up period, AIP patients followed up with CT exhibited a median cumulative radiation dose of 37.5 mSv. 11.3% of patients have accumulated doses exceeding 100 mSv. For the 169 patients followed over a year, 30.8% sustained an average annual radiation dose surpassing 20 mSv. The sensitivity/specificity/accuracy of CT for detecting abdominal organ relapse was 64.1%/99.6%/97.0%. For AIP patients followed up with MRI, the sensitivity for detecting disease relapse was 90.5%. Considering the accumulation of radiation dose in AIP patients and the insufficient sensitivity in detecting disease relapse with CT, safer and more sensitive imaging follow-up strategies should be explored. Question CT, as the primary imaging modality for autoimmune pancreatitis (AIP) follow-up, raises concerns regarding radiation exposure and lacks reported diagnostic performance in detecting AIP relapse. Findings CT in AIP follow-up causes significant cumulative radiation exposure and exhibits insufficient sensitivity in relapse detection. Clinical relevance Type 1 AIP necessitates long-term imaging follow-up, yet current guidelines lack consensus regarding the prioritization of CT or MRI for such follow-up. CT is widely used but has radiation concerns and limited sensitivity, calling for safer, efficient strategies.

Occupational Radiation Exposure During Intraoperative 3-Dimensional Fluoroscopy in Pelvis and Acetabular Surgery.

To quantify the occupational radiation exposure with a 3-dimensional (3D) fluoroscopic machine during routine use in pelvic and acetabular surgery and to determine whether the additional radiation exposure encountered with the 3D fluoroscopic spin is within previously accepted limits. Prospective cohort study. Level I trauma center. All patients undergoing 3D fluoroscopy intraoperatively during pelvis (OTA/AO 61B,C) or acetabular (OTA/AO 62A-C) surgery between April 2021 and July 2021. Radiation dose at standardized locations around the operating room during the spin portion of the 3D fluoroscopy. Seventy-six 3D spins were performed on 69 patients during the study period. The average emitted radiation dose from the machine for the routine fluoroscopy portion of the case was 74.5 mGy. The average displayed radiation dose in the air for the spin portion of the case was 39.9 mGy, an average of 53.6% less radiation than the routine fluoroscopy portion. For the spin portion, the average radiation exposure seen by the patient was 3.42 mGy (centered on the patient) and the average maximal exposure in the room was 0.062 mGy. Minimal radiation was detected outside the operating room doors. The radiation exposure encountered by operating room personnel with 3D fluoroscopy appears to be within safe occupational limits. The marginal increase in radiation exposure during pelvic and acetabular surgery should not discourage the use of 3D imaging intraoperatively. Level IV, Case Series.

Preoperative Tumor Growth Rate Does Not Predict Overall or Progression-free Survival in Patients With Glioblastoma.

Presurgical tumor volume progression in glioblastoma (GBM) may be a predictor of survival. This study aims to evaluate the potential impact of preoperative tumor growth and other clinical as well as laboratory parameters on overall survival (OS) of GBM patients. We retrospectively analyzed 98 adult patients with GBM who received two magnetic resonance imaging (MRI) scans between 2013 and 2023, before primary surgery and concurrent Stupp chemoradiotherapy. Tumor growth rates were calculated to classify GBM into slower and faster growing categories. Statistical analyses, including Kaplan-Meier and multivariable Cox regression survival analyses, were performed to evaluate the impact of various clinical and treatment-related factors on OS and progression-free survival (PFS). Slower growing tumors had a significantly longer doubling time than faster growing lesions. Univariable analysis showed no significant differences in OS (p=0.12) or PFS (p=0.4) when analyzed according to tumor growth. When stratified by O6-methylguanin-DNA-methyltransferase (MGMT) status, there were still no differences in OS (p=0.14), but in PFS (p=0.009). In the multivariable Cox regression analysis, radiation dose (p=0.02) and the number of adjuvant cycles of temozolomide (TMZ) (p=0.002) were significantly associated with OS. MGMT status (p=0.02) and the number of adjuvant TMZ cycles (p<0.001) were significantly associated with prolonged PFS. Specific volume growth rate (SVGR), patient age, baseline tumor volume, Karnofsky performance status, extent of resection, and total radiation dose were not significantly associated with PFS. SVGR was not significantly associated with OS or PFS. In contrast, MGMT status, radiation dose, and number of adjuvant TMZ cycles were identified as predictors of treatment outcomes. These factors can guide physicians when designing personalized treatment concepts for patients with GBM.

Evaluation of radiation dose to Korean population by general radiography

General radiography has the highest usage among diagnostic radiology in Korea, resulting in high radiation dose by general radiography. For the medical radiation safety of patients, it is necessary to evaluate Korean population dose by general radiography. In this study, collective dose and per capita effective dose from general radiography in the Korean population were calculated. To this end, the raw data on the usage of general radiography in Korea as of 2017 was analyzed. Moreover, information on radiation dose from domestic general radiography was collected and PCXMC was used to evaluate the effective dose for patients during general radiography. As of 2017, the usage rate for lower extremity and chest examinations was high, accounting for more than 20 % of the total general radiography examinations. The effective dose depending on the examination type was the highest for whole-spine AP (1.06 mSv), followed by whole-spine LAT (0.61 mSv), and lumbar spine AP (0.51 mSv). As a result of evaluating Korean population dose by general radiography, the collective dose was 22,066 man∙Sv and the per capita effective dose was 0.43 mSv. The evaluation results of the Korea population dose obtained from this study can contribute to patient dose management in general radiography.

Feasibility of Ultra-low Radiation and Contrast Medium Dosage in Aortic CTA Using Deep Learning Reconstruction at 60 kVp: An Image Quality Assessment

ObjectiveTo assess the viability of using ultra-low radiation and contrast medium (CM) dosage in aortic computed tomography angiography (CTA) through the application of low tube voltage (60kVp) and a novel deep learning image reconstruction algorithm (ClearInfinity, DLIR-CI). MethodsIodine attenuation curves obtained from a phantom study informed the administration of CM protocols. Non-obese participants undergoing aortic CTA were prospectively allocated into two groups and then obtained three reconstruction group. The conventional group (100kVp-CVgroup) underwent imaging at 100kVp and received 210 mg iodine/kg in combination with a hybrid iterative reconstruction algorithm (ClearView, HIR-CV). The experimental group was imaged at 60kVp with 105 mg iodine/kg, while images were reconstructed with HIR-CV (60 kVp-CV group) and with DLIR-CI (60 kVp-CI group). Student's t-test was used to compare differences in CM protocol and radiation dose. One-way ANOVA compared CT attenuation, image noise, SNR, and CNR among the three reconstruction groups, while the Kruskal-Wallis H test assessed subjective image quality scores. Post hoc analysis was performed with Bonferroni correction for multiple comparisons, and consistency analysis conducted in subjective image quality assessment was measured using Cohen's kappa. ResultsThe radiation dose (1.12±0.23 mSv vs. 2.03±0.82 mSv) and CM dosage (19.04±3.03 mL vs. 38.11±6.47 mL) provided the reduction of 45% and 50% in the experimental group compared to the conventional group. The CT attenuation, SNR and CNR of 60kVp-CI were superior to or equal to those of 100kVp-CV. Compared to the 60 kVp-CV group, images in 60kVp-CI showed higher SNR and CNR (all P < 0.001). There was no difference between the 60kVp-CI and 100kVp-CVgroup in terms of the subjective image quality of the aorta in various locations (all P > 0.05), with 60kVp-CI images were deemed diagnostically sufficient across all vascular segments. ConclusionsFor non-obese patients, the combined use of 60kVp and DLIR-CI algorithm can preserving image quality while enabling radiation dose and contrast medium savings for aortic CTA compared with 100kVp using HIR-CV.

Optimum radiation dose for palliation in head and neck squamous cell carcinoma (OpRAH) – A phase 3 randomized controlled trial

PurposeRadiotherapy is frequently employed for palliative treatment in locally advanced head and neck squamous cell carcinoma (HNSCC) but radiation dose fractionation regimens are not well-defined. We designed this phase 3 randomized controlled trial to compare two weekly hypo fractionated regimes and study the effect on progression-free survival (PFS) in this subset of patients. Materials and MethodsNon-metastatic locally advanced HNSCC patients (n = 305) who were not suitable for curative treatment were randomized to Arm A (20 Gy/5#/5 days) and Arm B (30 Gy/5#/5 days). PFS and OS were recorded along with acute toxicity using patient-reported quality of life HN QLQ 43. ResultsFrom April 2020 to August 2023, 390 patients were randomized, of which 305 were eligible for final analysis. At a median follow-up of 13.9 months, PFS and median overall survival (OS) for the entire cohort was 7.4 and 10.03 months, respectively. PFS (p-0.553) and OS (p-0.203) did not differ significantly between the two groups. Toxicity rates were similar between the two arms and dose escalation was well tolerated. Patients with a better PS were found to have significantly better OS. No significant benefit in OS or PFS was observed in patients who received neoadjuvant chemotherapy (NACT), underwent definitive conversion, or received palliative chemotherapy at progression. ConclusionThis is the largest phase 3 RCT to analyze the safety and efficacy of weekly palliative radiotherapy regimens and has not demonstrated further improvement with dose escalation

Multi-energy CT and iodinated contrast

Spectral CT acquires images with the emission or detection of two separate energy spectra. This enables material decomposition due to the photoelectric effect (prevalent in low-energy photons) and Compton scattering (prevalent in high-energy photons).Iodine and other materials with high atomic numbers appear more hyperdense on low-energy monoenergetic images because of the direct relation between the photoelectric effect and the Z value.Given the way iodine behaves on spectral maps, radiologists can optimise the use of contrast media in these CTs, thus allowing lower doses of radiation and lower volumes of contrast media while achieving the same CT values and even enabling lower contrast flow rates, which is especially helpful in patients with poor vascular access. Moreover, in suboptimal diagnostic cases caused by poor contrast opacification, the resolution can be improved, thus avoiding the need to repeat the study.

A metabolic switch to the pentose-phosphate pathway induces radiation resistance in pancreatic cancer

PurposePancreatic ductal adenocarcinoma (PDAC) is remarkably resistant to standard modalities, including radiotherapy. We hypothesized that metabolic reprogramming may underlie PDAC radioresistance, and moreover, that it would be possible to exploit these metabolic changes for therapeutic intent. Methods and materialsWe established two matched models of radioresistant PDAC cells by exposing the AsPC-1 and MIAPaCa-2 human pancreatic cancer cells to incremental doses of radiation. The metabolic profile of parental and radioresistant cells was investigated using Nanostring technology, labeled-glucose tracing by liquid chromatography-mass spectrometry, Seahorse analysis and exposure to metabolic inhibitors. The synergistic effect of radiation combined with a pentose-phosphate pathway inhibitor, 6-aminonicotinamide (6-AN) was evaluated in a xenograft model established by subcutaneous injection of radioresistant-AsPC-1 cells into nude mice. ResultsThe radioresistant cells overexpressed pyruvate dehydrogenase kinase (PDK) and consistently, displayed increased glycolysis and downregulated the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. Metabolic flux through the pentose-phosphate pathway (PPP) was increased, as were levels of reduced glutathione; pharmacological inhibition of the PPP dramatically potentiated radiation-induced cell death. Furthermore, the combined treatment of radiation with the PPP inhibitor 6-AN synergistically inhibited tumor growth in-vivo. ConclusionsWe provide a mechanistic understanding of the metabolic changes that underlie radioresistance in PDAC. Furthermore, we demonstrate that pancreatic cancer cells can be re-sensitized to radiation via metabolic manipulation, in particular, inhibition of the PPP. Exploitation of the metabolic vulnerabilities of radioresistant pancreatic cancer cells constitutes a new approach to pancreatic cancer, with a potential to improve clinical outcomes.

Effects of germination and gamma irradiation on physico-chemical and cooking qualities of pigmented red rice landrace: Ahu

The rice quality is influenced by various post-harvest treatments, including germination and gamma irradiation. The study investigates the combined effects of germination and gamma irradiation on the physico-chemical and cooking qualities of Ahu, a red rice landrace. The samples were subjected to germination for 0, 24, 48 and 72 hours and subsequently irradiated with gamma rays at doses of 0, 1, 2, 5 and 10 kGy. Post-treatment, samples were analyzed for proximate and mineral composition. Cooking quality parameters including cooking time, water absorption, and texture were also assessed. At a radiation dose of 2 kGy, both protein and carbohydrate content increased; however, they declined at higher doses. The ash content depicted a reduction with increased doses of radiation. Micronutrient composition remained largely unaffected by the irradiation process. Gamma irradiation also influenced cooking quality: water uptake ratio increased, while the optimum cooking time decreased at higher doses. Additionally, an upsurge of amylose content was demonstrated with increasing radiation levels, resulting in softer cooked rice. Thus, it can be attributed that dual processing of rice can effectively modify starch properties, rendering it a viable method for enhancing the textural and functional qualities.