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Background: Given the importance of scattered and low doses in secondary cancer caused by radiation treatment, the point dose of critical organs, which were not subjected to radiation treatment in breast cancer radiotherapy, was measured. Objective: The purpose of this study is to evaluate the peripheral dose in two techniques of breast cancer radiotherapy with two energies. Material and Methods: Eight different plans in two techniques (conventional and conformal) and two photon energies (6 and 15 MeV) were applied to Rando Alderson Phantom’s DICOM images. Nine organs were contoured in the treatment planning system and specified on the phantom. To measure the photon dose, fortyeight thermoluminescence dosimeters (MTS700) were positioned in special places on the above nine organs and plans were applied to Rando phantom with Elekta presice linac. To obtain approximately the same dose distribution in the clinical organ volume, a wedge was used on planes with an energy of 6 MeV photon. Results: Point doses in critical organs with 8 different plans demonstrated that scattering in low-energy photon is greater than high-energy photon. In contrast, neutron contamination in high-energy photon is not negligible. Using the wedge and shield impose greater scattering and neutron contamination on patients with low-and high-energy photon, respectively. Conclusion: Deciding on techniques and energies required for preparing an acceptable treatment plan in terms of scattering and neutron contamination is a key issue that may affect the probability of secondary cancer in a patient.

Background: It is essential to evaluate the accuracy of dose calculation for treatment planning systems (TPSs). This study's primary goal was to evaluate the accuracy of dose calculation for ISOgray TPS in the presence of a wedges in the treatment fields. Materials and Methods: GATE (Geant4 Application for Tomography Emission) as a Monte Carlo (MC) code was utilized to model the 6 MV photon beam of an Elekta Compact linac. It did MC code verification for three different field sizes and three depths for open, and wedged fields with gamma index tool. Following the confirmation, the percentage depth dose (PDD) and dose profile were calculated using the TPS and compared with the simulation results. In the next step, the TPS dose calculations for the 10×10cm2 field with different wedge angles were compared by the result from analytical formula. Results: The PDD and dose profiles for open fields met the gamma index criteria. However, there was disagreement for large wedged fields. The dose profiles of wedge angles using Petti analytical equation were compared to ISOgray dose profiles. Results showed that dose profile points with all wedge angles meet the gamma index criteria except for the 45° wedge angle. Conclusions: The results indicated that the disagreement between MC and TPS dose calculations increases by increasing wedge angle and field size. The uncertainty is due to TPS dose calculation algorithm causing noticeable disagreement. A MC-based TPS for dose calculation is recommended to reduce the error in dose calculation or at least medical physicist consider this issue. [ABSTRACT FROM AUTHOR]

Background and Objective: Failure to follow the standard guidelines in the selection and monitoring of infants before and during home phototherapy can result in unfavorable outcomes. The present study was conducted to determine the performance and complications of failure to follow the standard guidelines in infants undergoing home phototherapy in Mashhad, Iran. Methods: In this cross-sectional study, a total of 202 infants who were referred to neurology clinic or hospitalized at the emergency or neonatal wards due to acute or chronic outcomes of home phototherapy were included in 2020-2021. Gestational age, gender, birth weight, age at jaundice onset, age and duration of phototherapy, weight on admission, etiology of jaundice, referrer, phototherapy service providing center, type of breastfeeding, hyperthermia incidence, serum or skin bilirubin levels at the beginning and end of phototherapy, hematocrit, direct and indirect Coombs test, reticulocyte count, TSH, T4, G6PD, maternal age and blood type, parity, type of delivery, and pregnancy and delivery problems were recorded. Findings: The mean age of infants was 7.7±7.6 days, birth weight 2746±707 gr, admission weight 2601±771, bilirubin before home phototherapy 15.58±3.7 mg/dl, bilirubin on admission 17.5±5.8 mg/dl, and home phototherapy duration was 2.5±0.7 days. The frequency of causes of jaundice was as follows: ABO incompatibility (n=30), Rh incompatibility (n=22), urinary tract infections (n=13), fever and dehydration (n=19), hypothyroidism (n=7), biliary atresia (n=5), galactosemia (n=2), and etc. Thirty infants had pathologic weight loss, six had kernicterus, and three needed exchange transfusion. Conclusion: According to the findings of the present study, it seems that the non-compliance with the guidelines and standards for the selection of babies eligible for home phototherapy along with the lack of monitoring of the health status and serum bilirubin of these infants lead to serious consequences (dehydration and pathological weight loss, need for exchange transfusion and kernicterus) in them. It is necessary to closely review and monitor the process of diagnosis and referral of babies with jaundice who need phototherapy and treatment to phototherapy centers at home or hospital. [ABSTRACT FROM AUTHOR]