Assessment of using electronic portal imaging device for analysing bolus material utilised in radiation therapy

In this study, the feasibility of using electronic portal imaging device (EPID) as an analysing equipment for bolus material was evaluated in terms of its dosimetric parameters. Seven superflab bolus material samples, 4 samples of 0.5 cm (S1–S4) and 3 samples of 1 cm thickness (S5–S7), were analysed and compared with tissue equivalent water phantom, which was selected for reference material. Gamma analysis method was used to evaluate the dose distribution of the boluses. In addition, 487,204 point-dose values of each bolus were compared with the point-doses of corresponding reference material by using Spearman’s correlation coefficient analysis. The passing rates varied from 58.3 to 100% for 0.5 cm thick samples, and on the other hand, the passing rates of all the 1 cm thick boluses were 100%. All the correlation coefficient values were above 0.975. The correlation was statistically significant for all the samples (p < 0.001). The correlation coefficient of S4 bolus sample was the highest among the 0.5 cm thick bolus samples with a result of 0.989. Likewise, S5 and S6 bolus samples were the highest among the 1 cm thick ones with a result of 0.995. The results indicated that the material planned to be used as bolus can be evaluated with EPID in daily use.

L-carnitine protects the lung from radiation-induced damage in rats via the AMPK/SIRT1/TGF-1ß pathway

Radiotherapy (RAD) is a common cancer treatment method, but it can have unintended lung side effects. L-carnitine (LCAR) is an amino acid with antioxidant and anti-inflammatory properties. This study aims to demonstrate the effects of LCAR against radiation-induced acute lung injury and to elucidate its possible protective molecular mechanisms. A total of 32 Wistar albino rats were separated into four groups: control, RAD (10 Gy once on 1st day), RAD + LCAR (intraperitoneally, 200 mg/kg/d, for 10 days), and LCAR. At the end of the experiment, the rats were euthanized, and the lung tissues were collected for histopathological, immunohistochemical, biochemical, and genetic analysis. Emphysema, pronounced hyperemia, increased total oxidant status, and increased caspase-3 and TNF-α immunostainings were all seen in the lung tissues of the RAD group. LCAR treatment reduced these negative effects. In addition, AMPK and SIRT1 gene expressions increased in the RAD + LCAR group compared to the RAD group, while TGF-1ß gene expression decreased. While RAD caused major damage to the lungs of rats, LCAR application reduced this damage through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms. Specifically, LCAR reduced fibrosis while attenuating RAD-induced inflammation and oxidative stress via the AMPK/SIRT1/TGF-1ß pathway. Therefore, LCAR can be considered a supplement to reduce complications associated with RAD.

Evaluation of patient organ doses from kilovoltage cone-beam CT imaging in radiation therapy

Background

Currently, CBCT system is an indispensable component of radiation therapy units. Because of that, it is important in treatment planning and diagnosis. CBCT is also an crucial tool for patient positioning and verification in image-guided radiation therapy (IGRT). Therefore, it is critical to investigate the patient organ doses arising from CBCT imaging. The purpose of this study is to evaluate patient organ doses and effective dose to patients from three different protocols of Elekta Synergy XVI system for kV CBCT imaging examinations in image guided radiation therapy.

Materials and methods

Organ dose measurements were done with thermoluminescent dosimeters in Alderson RA NDO male phantom for head & neck (H&N), chest and pelvis protocols of the Elekta Synergy XVI kV CBCT system. From the measured organ dose, effective dose to patients were calculated according to the International Commission on Radiological Protection 103 report recommendations.

Results

For H&N, chest and pelvis scans, the organ doses were in the range of 0.03-3.43 mGy, 6.04-22.94 mGy and 2.5-25.28 mGy, respectively. The calculated effective doses were 0.25 mSv, 5.56 mSv and 4.72 mSv, respectively.

Conclusion

The obtained results were consistent with the most published studies in the literature. Although the doses to patient organs from the kV CBCT system were relatively low when compared with the prescribed treatment dose, the amount of delivered dose should be monitored and recorded carefully in order to avoid secondary cancer risk, especially in pediatric examinations.

Cardioprotective Effects of Dapagliflozin Against Radiotherapy Induced Cardiac Damage

BACKGROUND

With the increasing incidence of cancer among the adult population, radiotherapy (RT) is frequently used as a critical component in the treatment of various cancer types. Due to the nature of ionizing radiation, damage usually occurs within the tissues in anatomical neighborhood with the primary tumor localization. Dapagliflozin (DAPA), originally developed as an oral anti-diabetic medication, has been shown to have potent cardioprotective effects in the DAPA-HF trial. The cardioprotective effects of DAPA against RT induced cardiac cellular damage were investigated in this study.

METHODS

A total of 40 male Wistar albino rats were obtained and were subjected to a 10-day pretreatment period to accommodate laboratory settings. Afterwards, the rats were divided into 4 groups consisting of 10 each (control = 10, DAPA = 10, RT = 10, RT + DAPA = 10). Meanwhile, the RT and RT + DAPA groups received a single dose of 20 Gray (Gy) x-ray to 4 × 4 cm area at 0.60 Gy/min, and DAPA and RT + DAPA groups were gavaged daily with 10 mg/kg DAPA. In the second week of the study, rats were examined by echocardiography and electrocardiogram. Furthermore, histopathological method was used to evaluate the level of cardiotoxicity.

RESULTS

The ejection fraction value decreased by 17.3% lower in the DAPA + RT group compared with the RT group (P < .001). In addition, corrected QT interval prolongation and QRS widening were 11.5% and 17.4% higher in the RT group compared with the DAPA + RT group, respectively (P < .001 for both values). While sarcomyolysis, inflammatory cell infiltration, and necrotic changes were found to be severe in the RT group, the DAPA + RT group had 68% less sarcomyolysis, 64% less inflammatory cell infiltration, and 55% less necrosis (P < .001 for all values).

CONCLUSIONS

The protective effects of DAPA against left ventricular remodeling and dysfunction in RT-induced cardiomyopathy model were observed in this study.