The aim of this study was to investigate the risk of sensorineural hearing loss (SNHL) and the relationship between SNHL and radiation dose to the cochlea and frequency range of hearing loss in patients with head and neck cancer. Pure tone audiometry at 250-12,000 Hz was performed on 29 patients diagnosed with head and neck tumours who were treated with 3-dimensional conformal radiation therapy and followed up for 6 months. Paired t test indicated that the mean air conduction threshold before and after radiotherapy was significantly different (paired t test, p < 0.001). SNHL was observed in 15 patients (51 %) according to CTCAE. SNHL increased to 77 % in patients who had received at least five concurrent cisplatin cycles. There was an increased risk of SNHL for ears receiving a mean dose of 5000 cGy compared to those receiving <5000 cGy. SNHL was more severe at higher frequencies of pure tone audiometry in patients with cisplatin-based chemoradiation. The ototoxicity effect of radiation and cisplatin must be considered in the treatment of head and neck tumours. Increasing the dose of cisplatin, radiation dose of cochlea and follow-up interval time may result in increasing severity and frequency of hearing loss incidences. However, characteristic of radiation-induced SNHL seems to be different from chemoradiation-induced SNHL.

Background: To compare the dosimetric coverage of the planning target volume (PTV) and the dose delivered to the main Organs at Risk (OARs) in 5 and 7-field techniques of Intensity Modulated Radia%on Therapy (IMRT) in pa%ents with local prostate cancer. Materials and Methods: Twelve pa%ents with local prostate cancer underwent 5 and 7-field IMRT planning. The delivery of IMRT was carried out using the sliding technique. The dose coverage for PTV was designated to ≥98% of the PTV covered by 95% of the prescribed dose. Dose conformity was evaluated by comparing the volume of nontarget %ssue receiving maximum, and average of the prescribed dose and the dose of 33%, 50%, and 66% of the volumes on both planning sets. For target, this evalua%on was made with comparing the Conformity Index (CI) and Inhomogeneity Index (HI). In addi%on, we compared the monitor units used for dose delivery in both planning techniques. Results: All the 5 and 7field IMRT plans differed slightly in the measured parameters, and none of them have sta%s%cally significant differences with each other except for the monitor units where significant differences were observed in favor of the 5field IMRT plans (p=0.000). In all of the 5-field IMRT plans the mean dose delivered to OARs were very similar or less than that of the 7-field plans. Conclusion: In comparison to the 7-field technique, the 5-field IMRT technique has resulted in improved IMRT dose conformity, homogeneity, and lesser MUs used for radia%on therapy. However, this difference was not significant.

High radiation doses to the body may lead to the stochastic/deterministic effects of ionizing radiation on the critical organs as well as causing the cataract in eye lens of the clinical staff in interventional radiology. In this study, the received doses of the eyes, skin and whole body of 38 clinical staff including physicians, residents, nurses and radiotechnologists in cardiac angiography departments in three selected hospitals were assessed using personal dosemeters during two bimonthly dosimetry periods. Moreover, the correlation coefficients among the measured dose components including eye lens dose, skin dose and whole body dose equivalent in both area of under and over their lead-apron were calculated for all these occupational groups. The results show that the occupational annual dose values of the clinical staff are below the annual dose limits recommended by International Commission on Radiation Protection. Furthermore, among the measured dose components, the highest correlation coefficient value was obtained between the eye lens dose and personal dose equivalent measured over the lead apron for all the occupational groups.