Current practices of craniospinal irradiation techniques in Turkey: a comprehensive dosimetric analysis.

OBJECTIVE: This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution. METHODS: Anonymized CT scans of adult and pediatric patients, alongside target volumes and organ-at-risk (OAR) structures, were shared with 25 local radiotherapy centers. They were tasked to develop optimal treatment plans delivering 36 Gy in 20 fractions with 95% PTV coverage, while minimizing OAR exposure. The same CT data was sent to a US proton therapy center for comparison. Various planning systems and treatment techniques (3D conformal RT, IMRT, VMAT, tomotherapy) were utilized. Elekta Proknow software was used to analyze parameters, assess dose distributions, mean doses, conformity index (CI), and homogeneity index (HI) for both target volumes and OARs. Comparisons were made against proton therapy. RESULTS: All techniques consistently achieved excellent PTV coverage (V95 > 98%) for both adult and pediatric patients. Tomotherapy closely approached ideal Dmean doses for all PTVs, while 3D-CRT had higher Dmean for PTV_brain. Tomotherapy excelled in CI and HI for PTVs. IMRT resulted in lower pediatric heart, kidney, parotid, and eye doses, while 3D-CRT achieved the lowest adult lung doses. Tomotherapy approached proton therapy doses for adult kidneys and thyroid, while IMRT excelled for adult heart, kidney, parotid, esophagus, and eyes. CONCLUSION: Modern radiotherapy techniques offer improved target coverage and OAR protection. However, 3D techniques are continued to be used for CSI. Notably, proton therapy stands out as the most efficient approach, closely followed by Tomotherapy in terms of achieving superior target coverage and OAR protection.

An institutional experience of quality assurance of a treatment planning system on photon beam.

AIM: The purpose of the present study is to show the application of the IAEA TRS-430 QA procedures of Eclipse™v7.5 TPS for photon energies. In addition, the trends of the deviations found in the conducted tests were determined. BACKGROUND: In the past, the lack of complete TPS QA procedures led to some serious accidents. So, QA in the radiotherapy treatment planning process is essential for determination of accuracy in the radiotherapy process and avoidance of treatment errors. MATERIALS AND METHODS: The calculations of TPS and measurements of irradiations of the treatment device were compared in the study. As a result, the local dose deviation values (δ 1: central beam axis, δ 2: penumbra and build up region, δ 3: inside field, δ 4: outside beam edges, δ 50-90: beam fringe, RW50: radiological width) and their confidence limit values (including systematic and random errors) were obtained. RESULTS: The confidence limit values of δ 4 were detected to increase with expanding field size. The values of δ 1 and δ 3 of hard wedge were larger than open fields. The values of δ 2 and δ 50-90 of the inhomogeneity effect test were larger, especially than other tests of this study. The average deviation was showed to increase with the rise of the wedge angle. The values of δ 3 and δ 4 of lung irradiation were outside tolerance. CONCLUSIONS: The QA of TPS was done and it was found that there were no reservations in its use in patient treatment. The trend of the deviations is shown.

The potential cardioprotective effects of amifostine in irradiated rats.

PURPOSE: The aim of this study is to determine the cardioprotective efficacy of amifostine. The study consists of researching the relationship between plasma brain natriuretic peptide levels and the electrical and morphologic changes in irradiated rats with or without amifostine. METHODS AND MATERIALS: Sixty Wistar albino rats were divided into 4 groups, and their hearts were given 15 Gy/fraction with (60)Co. In Groups I and II, the rats were killed after 24 hours to detect early effects; in Groups III and IV, the rats were killed 100 days after irradiation to detect late effects. Before irradiation, Groups I and III received 0.9% saline solution, whereas Groups II and IV received amifostine (200 mg/kg). Twenty rats were used as a control group. RESULTS: On the 100th day, mild myocardial degeneration was detected in 5 rats (33%) from Group III (no amifostine). This percentage was statistically different from that of Group IV (treated with amifostine) and the controls (p = 0.042). There was no statistically significant difference between the mean plasma brain natriuretic peptide values of the groups (p > 0.05). There was no significant difference in electrocardiographies between the groups. There was no correlation between continuous variables. CONCLUSION: In the amifostine group (IV) on the 100th day, there was no myocardial degeneration, suggesting that amifostine has a cardioprotective effect.