Measurement of the contralateral breast photon and neutron dose in breast cancer radiotherapy: A Monte Carlo study.

INTRODUCTION: This study aimed to calculate the photon and neutron doses received to the contralateral breast (CB) during breast cancer radiotherapy for various field sizes in the presence of a physical wedge. MATERIALS AND METHODS: Varian 2100 C/D linear accelerator was simulated using a MCNP4C Monte Carlo code. Then, a phantom of real female chest was simulated and the treatment planning was carried out on tumoral breast (left breast). Finally, the received photon and neutron doses to CB (right breast) were calculated in the presence of a physical wedge for 18 MV photon beam energy. These calculations were performed for different field sizes including 11 cm × 13 cm, 11 cm × 17 cm, and 11 cm × 21 cm. RESULTS: The findings showed that the received doses (both of the photon and neutron) to CB in the presence of a physical wedge for 11 cm × 13 cm, 11 cm × 17 cm, and 11 cm × 21 cm field sizes were 9.87%, 12.91%, and 27.37% of the prescribed dose, respectively. In addition, the results showed that the received photon and neutron doses to CB increased with increment in the field size. CONCLUSION: From the results of this study, it is concluded that the received photon and neutron doses to CB in the presence of a physical wedge is relatively more, and therefore, they should be reduced to as low as possible. Therefore, using a dynamic wedge instead of a physical wedge or field-in-field technique is suggested.

Seizure Prevalence and Its Related Factors in Tramadol Intoxication; a Brief Report.

INTRODUCTION: Seizure is known to be a serious complication of tramadol consumption even in its therapeutic doses. The aim of this study was to determine the prevalence of seizure and its related factors in tramadol intoxicated patients referred to emergency department (ED). METHODS: In this cross-sectional study, all individuals, admitted to ED following tramadol intoxication were divided into two groups based on the presence or absence of seizures. Demographic data as well as clinical, electroencephalogram and imaging findings were compared between the two groups using SPSS software version 22. RESULTS: 167 patients with the median age of 23 (13-45) years were studied (85% male). Seizure was seen in 97 (58.0%) cases. Risk of seizure had increased 3.7 times in patients with a history of seizure (OR: 3.71 Cl 95%: 1.17 - 11.76). Tramadol dose was significantly higher in patients who had seizure more than once (Median: 2800 IQR: 1800-4000), compared to those who had one seizure episode (Median: 850 IQR: 1800-400) (p <0.0001). CONCLUSION: Based on the findings of this study, history of seizure increased the risk of seizure in patients taking tramadol, and the increase in dose correlated with a significant increase in seizure frequency.

The relationship between B7 homologous 1 with interleukin-4, interleukin-17 and interferon gamma in patients with allergic rhinitis.

Background: The etiology of allergic rhinitis includes an increase in cytokine levels, including IL- 4, IL-13, IL-17, and reduction in B7 homologous 1 (B7-H1) or programmed cell death-1 ligand-1 (PD-L1), a new member of the CD28: B7 stimulant molecule family. The aim of this study was to determine the relationship between cytokines and PD-L1. Methods: In this experimental study, 80 patients with allergic rhinitis were enrolled according to inclusion and exclusion criteria. The severity and stage of the disease were determined by a specialist physician. A 5 cc venous blood sample was collected from the patients. IL-4, IL-17, INFγ and PD-L1 were measured using ELISA technique. Results: There was a significant correlation between SPD-L1 and INFγ, IL-4 and IL-17 in allergic rhinitis patients (P < 0.05). Statistical analysis based on the severity of the disease (Mild, Moderate and Severe) showed a significant positive correlation between the SPD-L1 and INFγ in all three levels (P < 0.001). There was also a significant negative correlation between SPD-L1 and two cytokines IL-4 and IL-17 (P < 0.001). Conclusion: PD-L1 may have a protective role against allergic rhinitis, although the precise mechanism requires further detailed studies.

MEASUREMENT OF THE CONTRALATERAL BREAST PHOTON AND THERMAL NEUTRON DOSES IN BREAST CANCER RADIOTHERAPY: A COMPARISON BETWEEN PHYSICAL AND DYNAMIC WEDGES.

This research aimed to measure the received photon and thermal neutron doses to contralateral breast (CB) in breast cancer radiotherapy for various field sizes in presence of physical and dynamic wedges. The measurement of photon and thermal neutron doses was carried out on right breast region of RANDO phantom (as CB) for 18 MV photon beams. The dose measurements were performed by thermoluminescent dosimeter chips. These measurements obtained for various field sizes in presence of physical and dynamic wedges. The findings of this study showed that the received doses (both of the photon and thermal neutron) to CB in presence of physical wedge for 11 × 13, 11 × 17 and 11 × 21 cm2 field sizes were 5.92, 6.36 and 6.77% of the prescribed dose, respectively as well as for dynamic wedge were 2.92, 4.63 and 5.60% of the prescribed dose, respectively. The results showed that the received photon and thermal neutron doses to CB increase with increment of field sizes. The received photon and thermal neutron doses to CB in presence of physical wedge were more than dynamic wedge. According to obtained findings, it is suggested that using a dynamic wedge is preferable than physical wedge, especially for medial tangential field.

An overview on small-field dosimetry in photon beam radiotherapy: Developments and challenges.

Small fields are more repeatedly used for radiation therapy as small segments in intensity-modulated radiotherapy or as in the form of independent fields in stereotactic radiosurgery and other novel equipment such as cyberknife and tomotherapy. Nevertheless, the application of small fields for radiotherapy of lung makes the dose calculation and planning inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies within most of the analytical dose calculation algorithms. The current review attempts to gather the information in this regard and focuses on the current progresses and retaining issues associated with this type of photon beams.