International Journal of Radiation Research
Volume:20 Issue: 3, Jul 2022

This study aimed to investigate the radioprotective effect of liposomal silibinin (Lip-SIL) on human lymphocytes in the treatment of non-small lung cancer cells using a combined method of cell viability assay and cytokinesis-block micronucleus assay for a better evaluation of whether one active compound is suitable to be used as a radioprotector in radiotherapy or not.

Firstly, Lip-SIL was prepared by the lipid film hydration method combined with sonication. Secondly, penetration of Lip-SIL into cells was observed by fluorescence microscopy. Finally, the potential application of Lip-SIL as a radioprotector of human lymphocytes in the treatment of non-small cell lung cancer was evaluated using the above combined method with A549 cell line as a model.

The successfully prepared Lip-SIL had a spherical shape and good physical characteristics (particle size of approximately 83.9 nm, zeta potential of -20.6 mV, encapsulation efficiency of 28.8 % and payload of 5.1 %). At a SIL concentration of 10 µg/mL, Lip-SIL exhibited the highest radioprotection for lymphocytes, but showed no radioprotection or even increased genotoxicity in human lung cancer A549 cells.

Lip-SIL is a potential protector of human lymphocytes during radiotherapy in the treatment of non-small lung cancer. Moreover, the results of this study also imply that the radioprotection ability of bioactive compounds for normal cells is not only based on their scavenging activity on reactive oxygen species (ROS) but also on their mechanisms of intracellular activations.

We compare plans involving two different stereotactic radiotherapy devices: Cyberknife (CK) and Helical Tomotherapy (HTT) and their results on the lumbarvertebra targets. 

 Ten simulation tomographs of the first lumbar vertebra were selected from among the tomographies of patients who had previously undergone SBRT for any reason. In each planning tomography, two separate clinical target volumes (CTV) were drawn at the first lumbar vertebra, we used 2%, 95% and 98% doses of the target volume (D2, D95, D98) in the plan evaluation. The 2% dose of the planning target volume (PTV) was used for comparison with the hot spot; the 95% dose coverage of CTV was used for the target coverage comparison, and the 98% dose of the target volume was used for the dose volume histogram "shoulder" metric definitionTheHomogeneity Index (HI), new Conformity Index (nCI) and Gradient Index (GI) were evaluated for each planning system and target. 

 In both groups, CTV1 and CTV2, when compared with D95, the coverage for HTT was found statistically significantly higher. D98 was found to be statistically significantly higher with HTT. In both targets, the CKplans were found to have a higher hot area (D2), and inhomogeneous plans were obtained when compared to HTT. The NCI results were similar, and GI was higher with HTT. 

In lumbar vertebra stereotactic radiotherapy, more inhomogeneous plans were obtained with Cyberknife than with the Helical Tomotherapy device. A better gradient index was achieved with Cyberknife, while better coverage was achieved on the HTT plan.

To evaluate whether excluding the common iliac lymph nodes from the clinical target volume (CTV) during radiotherapy is effective in node-negative patients after cervical cancer surgery.

Between January 2014 and December 2017, 29 patients who underwent radiotherapy after curative surgery for cervical carcinoma were included in this study. We included 19 and 10 patients in the CTV group with common iliac lymph nodes (CTVL) and those without (CTVs), respectively. We retrospectively investigated the correlation among CTV, treatment outcome, and adverse events.

The median follow-up period was 30.4 (range, 2–55) months. The 3-year overall survival (OS) and progression-free survival (PFS) rates of the CTVL group were 95.0% and 85.0%, respectively, and those of the CTVs group were 100% and 88.9%, respectively. The 3-year OS and PFS rates were not significantly different between both groups (log-rank; P=0.414 and 0.657, respectively). Three CTVL patients and 1 CTVs patient had recurrences. However, there was no significant difference in the recurrence rate between both groups (P=1.0).

CTV excluding the common iliac lymph nodes in postoperative radiotherapy may be effective in patients with node-negative postoperative cervical cancer.

Low-dose ionizing radiation has major health impacts in a variety of fields, including radiation therapy. However, all potential applications are currently subject to public interest.

This study is an endeavor to evaluate the role of low dose gamma irradiation against the adverse effects of obesity in obese rats.

Thirty-six rats were divided into 4 equal groups;”G1” is a normal control group; ”G2” received a high-fat diet for 16 weeks to induce obesity; ”G3” rats also received a high-fat diet for 16 weeks in addition to being exposed to 0.5 Gray γ- radiation for 2 weeks, two twice a week (accumulated dose =4×0.5=2 Gray); “G4”  were normal rats, but also exposed to 0.5 Gray  γ- radiation for 2 weeks, twice a week (accumulated dose =4×0.5=2 Gray). Rats were anaesthetized at the end of the experiment, and blood samples as well as liver tissues were collected for both biochemical and histological studies.

There are harmful effects on the liver of obese rats, which include elevated levels of liver weight, liver functions, Malondialdehyde and lipids and diminished glutathione, as well as increased levels of C reactive protein and lipase in “G2” compared to “G1”. In contrast, low-dose fractionated gamma irradiation has a significant reduction in these harmful effects of obesity.

The findings of the current study suggest that fractionated low-dose gamma irradiation plays a significant role against the harmful effects of obesity, and thus could augment and support the aim of current study by drawing attention to the health impacts of low-doses gamma irradiation.

Although radiotherapy (RT) is an important treatment modality for cervical cancer, it can cause cancer. However, the risk of second primary cancer (SPC) tends to be ignored during RT for cervical cancer. We analyzed the prevalence and incidence patterns of SPC in cervical cancer patients that underwent definitive RT.

The insurance claims data of cervical cancer patients that underwent definitive RT from 2007 to 2012 were analyzed. Standardized incidence ratios (SIRs) were used to estimate the relative risks of SPC. In addition, odds ratios were estimated by unconditional Poisson regression and adjusted for age at cervical cancer diagnosis, chemotherapy, and comorbidities.

Median patient age was 59.4 years. SIRs for bladder, ovary, and uterine cancer were 6.72 (95% confidence intervals (CI) 3.36–12.03, p < 0.001), 7.12 (95% CI 4.22–11.25, p < 0.0001), and 8.44 (95% CI 5.08–13.18, p < 0.001), respectively. The SIRs of all organs in the pelvic irradiation field were significantly increased. SIRs for breast and stomach cancer were 0.5 (95% CI 0.22–0.99, p = 0.0441) and 0.8 (95% CI 0.43–1.37, p = 0.5331), respectively. SIRs were not affected by chemotherapy, age, or comorbidities.

RT increases the incidence of SPC in cervical cancer patients. In particular, SPC rates of organs in the irradiation field were higher than those of organs outside the irradiation field. If SPC risk were quantified with respect to irradiation dose, it could be utilized in clinical practice.

A combination of photodynamic and sonodynamic therapy (PSDT) may be a non-invasive method for cancer treatment, which incorporates a combination of low-intensity ultrasound, laser radiation, and a sensitizer agent. The goal of this research was to evaluate the effect of PSDT with Hematoporphyrin-encapsulated Mesoporous silica nanoparticles (HP-MSNs) as a sensitizer in the management of mice breast adenocarcinoma.

One hundred and fifty-six female mice (tumor grafted) were separated into 26 groups; including sham, laser (650 nm), 4 groups of laser + HP or MSN-HP (2.5 and 5 mg/kg), 4 groups of laser + ultrasound (1and 3 MHz; 1, 2 W/cm2), 16 groups of PSDT + HP or HP-MSN. The tumor growth factors were used to assess the procedure findings.

The results indicate that PSDT with an injection of HP or HP-MSN is effective in delaying tumor growth (P<0.05). Overall comparison of data showed a non-significant difference between PSDT with HP-MSN groups. The time of T2 and T5 in the groups of PSDT with HP-MSN were increased in comparison with sham and that of PSDT with HP groups (P<0.05). The tumor growth inhibition ratio increased in all PSDT groups. This increase was transient and declined over 30 days of treatment. PSDT + HP-MSN had Grade I, while other groups had Grade III malignancy in the histological study.

The research gave profound findings involving the employ of PSDT with HP-MSN as a photo/sonosensitizer for treating breast adenocarcinoma implanted in mice.

Natural The validation and clinical implementation of the PRIMO Monte Carlo (MC) model of Clinac®iX Linear accelerator as an independent dose verification and quality assurance (QA) tool for the SBRT lung treatment plans.

An independent MC based dose verification was performed for ten volumetric modulated arc therapy (VMAT) SBRT treatment plans.The plans generated in the Varian Eclipse treatment planning system (TPS) were recalculated with a PRIMO MC system for identical beam parameters.The log file-based QA was performed by comparing the TPS dose against the dose reconstructed from machine log files and the results were cross-verified with the Mobius3D® verification system. The dose-volume histogram (DVH) based plan comparison and 3D global gamma analysis were carried out. The statistical significance of the differences was tested with the Wilcoxon signed-rank test with a significance level of P < 0.05.

No statistically significant differences were observed in PTV and organs at risk (OARs) DVH parameters except for the PTVmax dose for both TPS vs PRIMO independent dose check and TPS vs PRIMO dynalog based QA. The 3D gamma analysis results show a minimum pass rate of 95% between TPS and PRIMO. Mobius3D® results showed a slightly higher percentage variation in the mean dose to PTV and OARs and a slightly lower gamma pass than TPS vs PRIMO results.

This study showed that a validated MC model of PRIMO could be used as an effective tool for independent dose verification and machine log-files-based quality assurance of VMAT SBRT plans.

A follow-up study of gamma knife radiosurgery has shown that postoperative radiation necrosis, radiation-induced edema, and malignant metastasis may occur. This may be due to secondary radiation exposure, therefore, it becomes necessary to actively reduce exposure to normal organs.

In this study, the secondary radiation dose to the surrounding normal organs was measured during gamma-knife radiosurgery for vestibular schwannoma disease. Using a human pediatric phantom and a glass dosimeter, a treatment plan was established according to the tumor volume, and then the exposure dose to important normal organs in both eyes, thyroid gland, sternum, and both lungs was measured.

According to this study, the cancer occurrence probability due to secondary exposure was calculated to be 7 cases per 100,000 people up to the case of the eye and thyroid gland. Exposure doses of 100.2±0.79 mGy or more were measured in both eyes, which is approximately 1000 times that of a chest X-ray or a flight from Seoul to New York. This indicates exposure through gamma knife surgery. The dose to the thyroid gland was 12.7±0.05 mGy, which exceeds the effective dose of 10 mSv in abdominal computed tomography.

By measuring the secondary exposure dose to normal organs during gamma-knife surgery for vestibular schwannoma disease, it was confirmed that the eyes and thyroid gland were exposed dangerously. Therefore, for pediatric patients specifically, a treatment plan that actively reduces secondary exposure is required.

To investigate the computer tomography (CT) features of 2019 coronavirus disease (COVID-19)-related pneumonia and its value for identifying severity.

Seventy-three patients with COVID-19 were divided into severe and nonsevere groups. CT signs were divided into two states: presence and absence; involvement range was divided into four grades; and affected lobes were divided into two states: ≥3 lobes and < 3 lobes; laboratory indices were divided into two states: normal and abnormal; co-occurrence of signs was divided into three states: ground-glass opacity (GGO) plus consolidation, only GGO, or only consolidation. The numbers of patients were respectively recorded. Statistical analysis was performed through the χ2 test, followed by multivariate logistic regression analysis.

Some indicators differed, including pure GGO (p<0.001), GGO with focal consolidation (p=0.009), patchy consolidation (p=0.004), sheeted consolidation (p<0.001), fibrotic appearance (p=0.020), involvement grade (p<0.001), affected lobes (p=0.027), pleural effusion (p=0.001), subpleural line (p=0.015), crazy paving signs (p<0.001), halo signs (p=0.020), thickened bronchial walls (p<0.001), air bronchi signs (p=0.003), lesions in mid/inner zone (p<0.001), liver function (p=0.044), interleukin-6 (p<0.001), c-reactive protein (p<0.001), lymphocyte count (p<0.001), and age (p=0.036). Pure GGO (OR:30.711, HR:1.292~729.882, p=0.034) and involvement grade (OR:0.017, HR:0.001~0.342, p=0.008) were independent risk factors.

On admission, CT signs of COVID-19-related pneumonia were diverse but characteristic, and some CT findings may be potential warning factors for severity, while a lack of GGO and extensive pneumonia may be independent risk factors.

This research was performed to analyze the relationship among the physical factors of cervical cancer patients and the V40-x (volume of the x receiving 40 Gy, x is replaced by bladder or rectum below). In addition, the methods to control the factors affecting these related physical parameters are comprehensively discussed so that the side effects of radiotherapy can be reduced.

Sixty cervical cancer patients treated with volume-modulated-arc therapy (VMAT) were selected. Related physical parameters of the planning target volume (PTV), rectum, and bladder were collected. The Spearman analysis method was used to discuss the relationship between the physical parameters and V40-x.

The parameter of Dmax-rectum (max dose of rectum) and Vbladder (volume of the bladder) were significantly negatively correlated with V40-rectum and V40-bladder, respectively. In addition, we found three dosimetric parameters and four parameters were significantly positively correlated with V40-rectum and V40-bladder. A reduction in V40-x of the organs at risk (OARs) was also displayed in the redesigned planning dose images and the dose-volume histograms (DVH).

It is recommended that patients maintain a filled bladder during localization and radiotherapy. It is also recommended that patients maintain an empty rectum during localization and radiotherapy to ensure the stability of the target. According to the correlation of the physical parameters obtained from the results, medical physics can reduce the V40-x more easily during planning design by specifically controlling some physical parameters, and this can reduce radiation toxicity more effectively.

The purpose of this study is to introduce a novel brachytherapy template called the Medanta anterior oblique‑lateral oblique template (MAOLOT), which has been designed for carcinoma cervix, and conduct its dosimetric comparison with Martinez universal perineal interstitial template (MUPIT).

Ten patients were chosen for this study with twelve intracavitary (IC) and/or interstitial (IS) applications. Plans were generated with basal points (BP), target points (TP), and inverse plan simulated annealing (IPSA) along with local graphical optimization (LGrO). Dosimetric and volumetric quantifiers including conformal index (COIN), dose non-uniformity ratio (DNR), dose homogeneity index (DHI), target dose homogeneity index (TDHI), and overdose volume index (OVI) were evaluated.

IPSA provided a better solution for DNR (range 0.25-0.48, p=0.04) in MUPIT and BP+LGrO method was appreciable (p=0.08) in OVI. Mean doses of D90, D95, and D98 of targets of LGrO plan were greater than their respective counterparts. Dose to 1cc and 2cc bladder was the highest for IPSA+LGrO plans as compared to forward optimization plans. Better COIN values were obtained for BP and TP plans with LGrO (p=0.043 (BP+LGrO), p=0.022 (TP+LGrO)). Mean EQD2 dose of 1cc and 2cc bladder was the highest for the IPSA plan as compared to other forward optimization plans.

In IC+IS application, small adjustments using LGrO improves the target coverage and reduces the normal structure dose. IPSA provides better results if plan evaluation is performed carefully. MAOLOT creates the intracavitary and interstitial dose distribution, which is comparable to MUPIT.

The objective of this study was to determine the long-term results of postoperative radiotherapy (RT) in patients with node-negative T1–T2 breast cancer and the prognostic factors affecting these results.

We retrospectively evaluated 382 node-negative breast cancer patients (pT1a–c, T2) treated with surgery. All patients underwent postoperative RT and 80% of patients received hormone therapy. Prognostic variables included patient characteristics, disease characteristics, and intervention factors. The primary endpoint was overall survival (OS). Survival curves were estimated using the Kaplan–Meier method. Differences in observed survival distributions among patient subgroups were evaluated using a two-sided long-rank test. We applied univariate and multivariate Cox models to evaluate predictive factors. Statistical significance was evaluated at a level of P < 0.05.

The median follow-up was 143 months. The 10-, 15-, and 20-year OS rates were 92%, 86%, and 80%, respectively. Univariate analysis showed that age (< 45, 45–65, > 65 years; P < 0.0001), comorbidity (P = 0.008), menopausal status (P = 0.03), and tumor stage (T1a–c, T2; P = 0.006) (table 1) were significant predictors of OS. Multivariate analysis showed that age (< 45, 45–65, > 65; P = 0.01) and tumor stage (T1a–c, T2; P < 0.0001) were independent predictors of OS. At age 15 years, the OS rate of patients with T1b, T1c, or T2 stage cancer was 87.5%, 81%, or 77%, respectively.

Age and tumor stage were independent prognostic factors for women with node-negative early breast cancer.

The aim of this study was to evaluate the influence of lesion size on the performance of real-time two-dimensional shear wave elastography (2D-SWE) in the diagnosis of breast lesions.

A total of 118 consecutive female patients with 129 breast lesions (50 malignant and 79 benign) who underwent surgical excision and/or core biopsy were studied. The lesions were categorized into three subgroups according to their size: (1) group 1: < 1.0 cm3; (2) group 2: 1.0–4.0 cm3; (3) group 3: > 4.0 cm3. The maximum elasticity (Emax), mean elasticity (Emean), and their standard deviation (SD) in the three subgroups were compared and analyzed in terms of the cutoff values acquired by pathological results.

The lesion size significantly differed between benign and malignant masses (P < 0.05). Malignant lesions exhibited significantly elevated values of Emax, Emean, and SD, compared with benign lesions in the three subgroups. The optimal threshold was higher for larger malignant and benign lesions (P < 0.05). In malignant lesions, the SWE parameters in group 1 were significantly different from those in groups 2 and 3. The area under the receiver operating characteristics curve (AUROC) of SD was higher than that of Emax and Emean in all three subgroups.

The values of 2D-SWE parameters  increase with the increase in size of a breast mass, and the adjustment of the threshold based on lesion size yields a more accurate diagnosis. Among the SWE parameters, SD has the best diagnostic performance.

Currently, many researchers focus their work on the effects of bio-nanoparticles inside the tumor during proton therapy. Indeed, these bio-nanoparticles enhance the absorbed dose especially if they have been settled at the Bragg peak zone. The main goal of this study is to give a new technique that improves and facilitates the clinical protocol during proton therapy for brain tumors by adding nanoparticles to the tumor and using a rotary accelerator with high energy (200 MeV).

With the use of the Monte Carlo Geant4 code, we simulated a proton therapy of a tumor located in the center of a human head containing bio-nanoparticles. The proton beam energy was chosen large enough to avoid having Bragg's peak at head level.

The results revealed that there was an optimization in the deposited energy at the tumor, at the same time the deposited energy at healthy tissue was less compared to ordinary proton therapy. It also showed that the platinum is the most effective bio-nanoparticles used in this work.

The addition of bio-nanoparticles to tumors and the use of a high-energy (200 MeV) rotary accelerator improve and facilitate proton therapy. This new technique allows the direction angle of the proton beam to be changed regardless of the position of the tumor, making it effective against moving tumors and preserving healthy tissue. In addition, the dose deposited in the tumor can be increased just by pivoting the head of the accelerator around the organ.

Recently, it has been demonstrated that thermosetting polymer composites have excellent gamma-rays shielding properties. Among them, phthalonitrile composites are the best suitable materials to replace the traditional shielding materials such as lead and concrete. Furthermore, tungsten-boride as high Z-material is an effective ionizing radiation shield.

The gamma rays shielding properties of the phthalonitrile matrix (PH) reinforced with tungsten-boride (WB) at 661, 1172, and 1332 keV photon energies were investigated using MCNPX code and XCOM tool kit and compared to those of concrete as conventional shielding material and epoxy composites. MCNPX geometry was defined along the z-axis and described in the input file. The number of emitted photons was fixed at 107 at the source, which is supposed to be a monoenergetic point.

The simulated mass attenuation coefficients results are in good agreement with those calculated using the XCOM tool kit. Also, it was observed that at 661 keV photon energy, the shielding performances in term of Half-Value-Layer (HVL) are enhanced by3.08% and 22.01% for 30% and 50% of tungsten-boride concentrations compared to 30% of PbO concentration in the Epoxy-Clay composite and concrete respectively.

In this study, the outstanding results of gamma-rays shielding properties of Phthalonitrile/WB composites (PHWB) obtained using MCNPX code and XCOM can be used for future experimental gamma-rays shielding approaches at a wide range of energy.

To explore the changes of brain function and structure after radiotherapy (RT) for nasopharyngeal carcinoma (NPC), to investigate their correlation with altered cognitive function and to promote the recognition of radiation-induced brain injury (RBI).

Resting-state functional MRI (rs-fMRI) and three dimensional (3D) T1-weighted imaging scans were conducted on 32 patients and 34 healthy subjects. Cognitive function was assessed in all subjects using multiple cognitive scales. Differences in regional homogeneity (ReHo) and brain gray matter (GM) volumes between groups were analyzed using the DPARSF package and VBM methods.

ReHo in Cerebelum_Crus2_L of the NPC patients was significantly higher than that in the controls, and was significantly correlated with memory, general cognitive function, and executive ability. The GM volumes in right fusiform gyrus (FFG.R), left temporal pole: middle temporal gyrus (TPOmid.L), left inferior temporal gyrus (ITG.L), Cerebelum_6_L, and left middle frontal gyrus (MFG.L) in the patients were significantly reduced compared with the controls, and were markedly correlated with multiple cognitive scale scores.

Damage to brain after radiotherapy mostly involving the temporal lobe and cerebellum, manifested by a compensatory increase in ReHo and a decrease in GM volume, both of which were significantly correlated with multiple cognitive impairments. ReHo and brain GM volume can be considered as sensitive biomarkers to monitor RBI.

Radiolabeling process has a very important role in prediction of in-vivo biodistribution. Moreover, biodistribution is considered the backbone of the recent discovery of anti-cancer drugs.Technetium-99m has been the most utilized radionuclide in nuclear medicine due to its optimal physical characteristics.

Oseltamivir(Osel) was radiolabeled by technetium-99m under reductive conditions directly.1.5 mg of Osel was followed by 25 μg of SnCl2. H2O, 200 μl buffer pH 4 at 60ºC reaction temperature, and the reaction time was 30 minutes. In-vivo biodistribution of 99mTc-Oseltamivir (99mTc-Osel) tracer was studied using tumor-bearing Albino mice compared to control. The radiochemical purity percentage was calculated using the ascending paper chromatography technique and also, confirmed by paper electrophoresis before the in-vivo biodistribution in mice.99mTc-Osel tracer was further analyzed utilizing high performance liquid chromatography analysis .Spartan software for molecular modeling is used for optimizing the different complex patterns of Osel with 99mTc where energy was minimized using the semi-empirical method with a PM3 basis set.

99mTc-Osel tracer was synthesized with a good yield of 98.7±0.34% at the optimized conditions and the preparation exhibited in-vitro stability up to 3 h. In vivo biodistribution studies showed high uptake in tumor cells with the target to the non-target ratio of 4.55±0.2 after 3 h. post- injection.

99mTc-Osel tracer focuses on the tumor site with a high percentage appropriate to use 99mTc-Osel as a useful tool for tumor imaging.

To elucidate the efficacy and toxicity of brain re-radiotherapy for recurrent large inoperable gliomas using radiosurgery.

Between 2014 and 2018, extreme hypofractionated radiosurgery was performed using Accuray’s Cyberknife® system on 14 lesions (12 patients)  grade 4 recurrence lesions of 6 patients with anaplastic astrocytoma and 6 patients with glioblastoma who had previously undergone surgery and cranial radiotherapy and had a local-regional recurrence. Six patients (8 lesions) were given a biologic effective dose (BED10) of 48 Gy and lower, and six patients were given a BED10 of 59.5 Gy and higher. The Response Assessment in Neuro-Oncology Criteria (RANO) were used for tumor response, and the Common Terminology for Adverse Events (CTCAE) was used for adverse effect assessment. The primary endpoint was determined as overall survival, and first treatment and salvage treatment time.

The median age of the patients was 43 years, and the median Karnofsky Performance Status (KPS) was 70. The median time from the first radiotherapy to death was 34 months. The median time from the previous radiotherapy was 29.5 months (R:17-40). The median survival was 10 months for those with recurrence before 29.5 months and 11 months for those with recurrence after 29.5 months. The median total tumor volume was 29.224 mL (~30 mL). One grade 4 toxicity was observed.

Radiosurgery can be used effectively as salvage therapy in ultra-large inoperable gliomas.

The present study aimed to investigate flap status in relation to the timing of radiotherapy (RT) in an experimental rat model of irradiated transverse rectus abdominis musculocutaneous (TRAM) flap.

Fifty-six adult male Sprague-Dawley experiments were separated in seven groups in terms of flap surgery and RT. The groups comprised sham group, control (Ctrl) group, RT group, and RT plus surgery (RT+Surg) group, which was further separated in four groups depending on the timing of postoperative RT as RT+Surg-10 (RT on postoperative 10th day), RT+Surg-20 (RT on postoperative 20th day), RT+Surg-30 (RT on postoperative 30th day), and RT+Surg-40 (RT on postoperative 40th day). All the rats were sacrificed 8 weeks after the RT administration for histopathological analysis.

Compared with the RT+Surg-10 and RT+Surg-20 groups, the hyalinization and collagenization scores in RT+Surg-30 were determined to be significantly lower. Fibrosis scores were lower in the RT+Surg-30 group compared with the RT+Surg-20 group, whereas significantly lower inflammation scores were determined in the RT + Surg-40 group and significantly higher dermal thickness in the RT+Surg-30 group compared with the RT+Surg-10 group.

The findings from this model of irradiated flap revealed the significance of the time lag among flap application and postoperative RT for histopathological outcome, emphasized the potential role of at least a 30- to 40-day interval between surgery and RT in achieving more favorable flap status.

It has been found that the bystander effect plays a key role in the survival of cells exposed to highly non-uniform radiation beams. However, the linear-quadratic (LQ) model cannot predict these effects well. The present study aimed to explore the potential impact of the radiation-induced signaling effects on treatment plans for spatially fractionated radiation therapy (SFRT) using a numerical radiobiological model. 

 Two tomotherapy-based SFRT plans were created using commercially available software in this work. The tumor response to these plans was modeled by both the conventional LQ model and a bystander model incorporating the indirect effect of radiation. We have investigated how dose-volume histograms (DVHs), dose distribution, equivalent uniform dose (EUD), and mean dose change with radiation-induced signaling effects. 

 When the intercellular signaling effects are included in the predictive survival model, the cell-killing within the low-dose regions of GRID fields increases. This leads to an increase in the EUD and means dose. These effects are more striking for the LATTICE radiotherapy plan, which contains high dose gradients in three dimensions. 

 Incorporating radiation-induced signals in tumor cells response to SFRT significantly deviates from the LQ model predictions. Therefore, it is recommended to use the radiobiological models which take both the signaling and radiation effects into account to predict survival in highly modulated radiation beams, especially in LATTICE radiotherapy.

In regard to the enhanced use of mammography screening tests for screening breast cancer, some concerns on the enhancement of the patient's absorbed dose have increased as well. Therefore, the assessment of the patient's dose before mammography is very important, and being aware of the dose level by its estimation can be helpful before radiation.

To this end, an artificial neural network (ANN) was used in this study to estimate the entrance surface air kerma (ESAK). A phantom with similar characteristics of the breast tissue was also used to collect the required data and the network was trained using some measurable parameters. To conduct the current research, multilayer perceptron (MLP) neural network architecture with training algorithms of LMBP, SCGBP, Rprop, BFGS, and GDBP, as well as radial basis function (RBF) neural network were used.

The results show that the neural network with BFGS training algorithm and 38 hidden layer neurons has the best performance with 7.40% root mean square error (RMSE) and coefficient of determination (R2) was obtained as 0.91.

According to the results of this study, there is a good correlation between the estimated network output and the measured values of the ESAK. The present method will remove the limitations and costs associated with the preparation process of dosimeter instruments.

Environmental radioactivity measurement of soil samples from the densely populated community has become imperative considering the radiological exposure associated with primordial radionuclides.

Sixty soil samples were collected at different locations within Alvan Ikoku Federal College of Education (AIFCE) and Federal Polytechnic Nekede (FPN), Owerri. Radioactivity measurements were carried out by the method of gamma-ray spectrometry with thallium doped sodium iodide [NaI(Tl)] detector.

The mean activity concentrations of 88.41±1.51, 20.69±3.56 and 25.04±0.71 Bqkg-1 for 40K, 226Ra and 232Th, respectively, were obtained in soil samples of AIFCE, while 92.97±1.50, 20.48±3.21 and 22.36±0.70 Bqkg-1 for 40K, 226Ra and 232Th, respectively, were obtained in soil samples of FPN. These values are below the average world value of 420, 32 and 45 Bqkg-1 for 40K, 226Ra and 232Th, respectively, as recorded in UNSCEAR 2000 report. The calculated absorbed dose, annual effective dose and other radiological hazard indices were below the recommended safe limit. The mean calculated values of the excess lifetime cancer risk for AIFCE and FPN are 0.12±0.03 and 0.11±0.03, respectively.

Based on the results from the present study, it is evidence that the activity concentrations and other radiological parameters are within the world’s safe limit, indicating that soil samples from the AIFCE and FPN, Owerri are free from radioactive contamination and do not pose a threat to the two communities.

To study the relationship between high-resolution computed tomography (HRCT) signs and the pathological subtypes and differentiation degree of lung adenocarcinoma.

We retrospectively reviewed HRCT images of 394 lung adenocarcinoma cases and compared the diversity of images among preinvasive lesions (PILs), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) and the differentiation degrees of IAC by Kruskal-Wallis and χ2 tests.

There were significant differences in the size, density and incidences of the pleura traction sign, spicule sign, lobulation sign, tumor vascular sign, bronchial cutoff sign, air bronchogram sign and cavity sign of PILs, MIA and IAC (χ2=2.172~247.077, P<0.05). The incidences of all these signs (except for the cavity sign) in IAC were higher than those in the other two groups (P<0.05). There were no significant differences in margin irregularity or vacuole signs among PILs, MIA and IAC (P>0.05). There were significant differences in the size, density, and incidences of margin irregularity, the pleura traction sign, the spicule sign, the lobulation sign, the tumor vascular sign, the bronchial cutoff sign and the cavity sign in the three differentiated subgroups (χ2=6.818~63.331, P<0.05).  No significant differences were found in the air bronchogram sign and vacuole sign among the three differentiated subgroups (P>0.05).

HRCT signs of lung adenocarcinoma are closely related to the pathological subtype and differentiation degree and have great value in helping predict tumor types and devise clinical treatment plans.

The optimal inter-fraction interval in fractionated thoracic radiosurgery remains unclear. Several institutions maintain at least a 48-hour interval between each radiosurgery fraction. However, evidence supporting such radiosurgery schedule is lacking. Since 2014, we have performed daily fractionated thoracic radiosurgery without interruption. In this study, we evaluated the safety of daily administration of fractionated thoracic radiosurgery in patients with primary or metastatic lung cancer. 

Patients who received radical or salvage fractionated radiosurgery for treatment of primary or metastatic lung cancer were included in this study. All patients received fractionated radiosurgery divided into 2-4 fractions administered daily without interruption. Radiosurgery-induced toxicities were evaluated.

Eighty-eight patients and 94 lung masses were treated. Radiosurgery-induced leukopenia and grade 5 toxicity did not occur. One patient experienced radiosurgery-induced grade 4 pneumonitis and dyspnea. Grade 3 pneumonitis, dyspnea, and fatigue developed in 23 (24.5%), 2 (2.1%), and 2 (2.1%) patients, respectively. Four (4.3%) patients experienced rib fracture. Dyspnea, fatigue, nausea, and pneumonitis were more common and severe in patients with central lung lesions. In contrast, dermatitis and rib fracture developed only in patients with peripheral lung lesions.

Daily fractionated radiosurgery is safe and well-tolerated in patients with primary or metastatic lung cancer. For patient convenience and better treatment outcomes, daily-fractionated thoracic radiosurgery can be considered.

For various practical reasons in radiotherapy practice, it is very advantageous to have linear accelerators dosimetrically matched. The present work assesses the extent of beam matching by investigating the similarity of dosimetric data from three Clinac-iX accelerators in photons (6, 18 MV) and electrons (6, 9, 12, 16 and 20 MeV) mode.

The following study is based on detailed comparisons of measured and determined parameters such as percent depth doses (PDDs), cross-plane beam profiles, flatness, symmetry, penumbra and dosimetric leaf gap, MLCT interleaf transmission factor, quality index, Relative output factor, in addition of depth R50, therapeutic range R90 and particle range Rp of electron beam.

The current measured data, for both photons and electrons, exhibited satisfactory degree of agreement among the three Clinac-iX. For 6 MV and 18 MV photons energies the maximum deviation of percentage depth does not exceed 0.4 %. For electron depth dose measurements (dmax, R50, R90, Rp) the results revealed a maximum deviation of 0.54 mm for all electron energies and applicators. As a direct clinical application, a left breast and prostate cancer cases were planned on the three Clinac-iX machines and compared for their dose volume histograms.

In clinical applications, the patient’s treatment can be shifted from one Clinac-iX to another without reducing the treatment quality in the case of periodic preventive maintenance or interruption of the functioning of the Clinacs; the treatment can be preserved without having to replan.

The Helical Tomotherapy (HT) technique has been introduced for use in Stereotactic Radiosurgery (SRS). Previously, the smallest field width (FW) has been recommended for optimum results, which would require a long beam-on time (BoT). The uncertainty of the intrafraction could be maximized during the delivery by this BoT. This study then investigated the plan qualities and dosimetric parameters among different FWs and treatment modes.

Fifteen patients previously treated by the HT technique with fixed-FW 10 mm (FW10f) were selected. The treatment planning systems of TomoTherapy involved other plans that employed fixed-FW 25 mm (FW25f) and dynamic-FW 25 mm (FW25d). The plan quality indexes and the dosimetric parameters of the large FWs (FW 25 mm) were compared according to the FW10f benchmark and then analyzed by relevant statistics.

The plan quality indexes and the dosimetric parameters revealed no significant differences between FW10f and FW25d. Accordingly, FW25f revealed a significant difference in the FW10f values in some indexed parameters. The maximum dose on the right optic nerves and the value of the integral dose revealed a significant difference between FW10f and FW25f. The BoT of the FW10f presented the longest treatment time when compared with the other FWs.

The outcomes of this investigation clearly ensure that the performance of FW25d is comparable with that of FW10f in terms of the plan qualities and the dosimetric parameters. Notably, the short BoT of this FW might benefit the minimization that is associated with intrafraction uncertainty.

The aim of this study was to compare the dosimetric properties of various water- equivalent phantom materials, such as solid water WT1 (WT1), solid water RMI457 (RMI457), plastic water, virtual water, polymethyl methacrylate (PMMA), polystyrene and A150, with water phantom.

Percentage depth dose values were obtained with IBA Blue Phantom2 and solid water phantom (RW3) used in clinical radiotherapy. The measurements were carried out at 6 and 18 MV photon energies with a field size of 10 x 10 cm2 and source-skin distance (SSD) at 100 cm. Simulations for the commercial solid phantoms were performed under these same conditions using Geant4 Application for Tomographic Emission (Geant4/GATE) simulation code.

PMMA (3.66±1.43) % and A150 (2.40±2.20)% phantom materials were determined to have a low rate of water equivalence at 6 MV photon energy while WT1 (-2.80±2.17)% and plastic water (-2.04±2.13)% phantom materials showed a low rate of water equivalence at 18 MV photon energy. Solid water WT1 (0.13±1.11)% and RMI457 (-0.29±0.91)% phantom materials were seen to be good water-equivalent materials at 6 MV photon energy, while PMMA (-0.08±1.39)% and A150 (-1.08±1.53)% were the closest equivalent materials to  water at 18 MV photon energy.

All the materials examined in this study were found to be suitable for the daily dosimetric measurements in clinical applications. The most appropriate choice would seem to be to use water phantom for the dosimetric measurements in radiotherapy clinics depending on the possibilities and time.

Radiation Therapy is a critical component of cancer treatment. During the course of their illness, at least half of cancer patients will require radiotherapy. It is primarily used as an adjuvant treatment after surgery, as a definitive treatment in inoperable tumors, and it also plays an important role in palliative care, such as pain management. Because establishing a radiation facility is a large undertaking, low-income countries such as Nepal have few radiation facilities. People must travel for hours to get to the closest Radiation Therapy Center, and hospitals are congested, so treatment takes months. Disease progression and untimely cancer mortality occur as a result of the delay in treatment and the paucity of standard radiation facilities. The purpose of this research is to determine the current state of radiation therapy infrastructures, human resources, and educational institutions, as well as to establish future development priorities.

Pigmented villonodular synovitis (PVNS) is a rare benign proliferative disease of the synovium which most commonly affects the knee. It is regarded as a benign disease, but has a local invasion. Postoperative adjuvant radiotherapy is very necessary for PVNS, but there is no consensus on the total dose of radiotherapy. 

 A 22-year-old young male with diffuse PVNS of right knee was referred to our hospital with ongoing right knee swelling and limitation of motion of the knee. Preoperative magnetic resonance imaging (MRI) showed synovium of the joint was obviously thickened with multiple nodular low signals of long T1 and short T2 which is the typical characteristic of PVNS. The patient was treated with arthroscopic synovectomy combined with adjuvant postoperative low-dose external radiotherapy (20 Gy).

 Based on related literature about radiotherapy of PVNS, arthroscopic synovectomy combined with postoperative low-dose external radiotherapy is an ideal treatment and prevents the recurrence for PVNS of the knee.

The high incidence of intracranial aneurysms and the high mortality rate after rupture highlight the requirement and importance for early and accurate visualization of the aneurysm profile for subsequent patient treatment. Here we report a patient with an intracranial aneurysm who underwent digital subtraction angiography (DSA), zero echo time MRA (ZTE-MRA), and three-dimensional time-of-flight MRA (3D-TOF-MRA) on admission and after operation. The imaging quality and accuracies of ZTE-MRA and 3D-TOF-MRA were compared with DSA, the gold standard, in pre-operative and post-operative evaluation of intracranial aneurysms. Comparison of the two MRAs, ZTE-MRA has greater advantages in imaging.