PURPOSE:This study aimed to investigate the risk factors and predictive value of vertebral Hounsfield units (HUs) for vertebral compression fracture (VCF) development in gastric cancer (GC) patients who received adjuvant radiotherapy (RT). MATERIALS AND METHODS:We retrospectively analyzed the data of 271 patients with non-metastatic GC who received adjuvant RT between 2010 and 2020. The vertebral bodies from 9th thoracic (T9) to 2nd lumbar (L2) were contoured in computed tomographies used for RT planning, and V30, V35, V40, mean doses, and HUs of vertebrae were documented. We conducted univariate and multivariate analyses to identify the risk factors for VCF development. RESULTS:The median follow-up time was 35.7 months. VCF developed in 23 patients (8.5%) in a median of 30.6 months (range, 3.4 to 117.3) after the end of RT. In total, 37 vertebrae were fractured, with 14 located in T12, nine in L1, seven in T11, four in L2, and three in T10. Older age, female sex, non-smoking status, and lower median vertebrae HUs were significantly associated with VCF in the univariate analysis. In the multivariate analysis, lower median HUs of T12 vertebrae (odds ratio, 0.965; 95% confidence interval, 0.942 to 0.989; p = 0.004) remained significant. The optimal cut-off value for T12 HU was 205.1, with an area under the receiver operating characteristic curve of 0.765, sensitivity of 85.7%, and specificity of 65%. CONCLUSION:The lower median HU value of T12 vertebrae is a significant and independent risk factor for VCF development in GC patients who received adjuvant RT. HUs values serve as a simple and reliable predictor of VCF development in this population.

AIM:To evaluate the oncological outcomes and the prognostic factors for children with ependymoma who receive radiotherapy (RT) ± chemotherapy after surgery. MATERIAL AND METHODS:The medical records of 71 children with ependymoma who received RT between 2001 and 2022 were retrospectively evaluated. Survival outcomes and prognostic factors were analyzed using log-rank and cox-regression tests. SPSS v24.0 was utilized for statistical analyses. RESULTS:Gross total resection (GTR) was achieved in 37 (52%) patients. Craniospinal fluid (CSF) seeding was observed in 8 (11%) patients at the time of diagnosis. The median RT dose was 54 Gy (42-60 Gy). The median time from surgery to the first RT was 2.4 months (1-109 months). The median follow-up time was 65.9 months (2.5-242.8 months), and 5-y overall survival, progression-free survival (PFS), and local recurrence-free survival (LRFS) were 74%, 39%, and 46%, respectively. Recurrence was observed in 41 (58%) patients. Among patients who initiated treatment with chemotherapy, 5-y PFS and LRFS were higher in patients who received RT at the time of diagnosis than those who received RT at the progression (23% vs. 0%, p < 0.001 and 39% vs 0%, p < 0.001). In multivariate analysis, increased time from surgery to radiotherapy was found to be a poor prognostic factor for PFS. CONCLUSION:Young age, less than GTR, large residual tumor volume, initiation of treatment with chemotherapy after surgery, and increased time from surgery to radiotherapy may deteriorate survival. RT should not be delayed until progression, even in young patients receiving chemotherapy.

Radiotherapy for non-small-cell lung cancer (NSCLC) requires precise tumour targeting and monitoring of anatomical changes to optimize outcomes. Daily kilovoltage cone-beam computed tomography (kV-CBCT) enables real-time tracking of tumour volume and electron density changes, which may affect dose distribution and radiobiological outcomes, such as Tumour Control Probability (TCP) and Normal Tissue Complication Probability (NTCP). This study evaluated inter-fractional changes in gross tumour volume (GTV) and electron density using kV-CBCT and their impact on dosimetric and radiobiological endpoints to assess the role of CBCT in adaptive radiotherapy. Twenty inoperable NSCLC patients receiving intensity-modulated radiotherapy (IMRT) with a prescribed dose of 60 Gy in 30 fractions were included in this retrospective study. Daily kV-CBCT images were acquired on the 1st, 15th, and 30th fraction to re-contour GTV and measure electron density changes in the GTV and ipsilateral lung (V30 volume, defined as lung volume receiving ≥ 30 Gy excluding GTV). CBCT images were fused with planning CT for dose recalculation using a Hounsfield unit-to-density calibration. Changes in GTV volume, electron density, maximum dose, and volume receiving ≥ 2.1 Gy/fraction were analyzed. TCP and NTCP were calculated using the Equivalent Uniform Dose (EUD) and Lyman-Kutcher-Burman (LKB) models, respectively. Statistical significance was assessed using ANOVA (p < 0.05). GTV volume decreased significantly by 3.4–59.7

OPINION STATEMENT:Uveal melanoma is the most common primary ocular tumor in adults. With the evidence demonstrating that episcleral plaque brachytherapy (EPB) has similar survival rates as enucleation in the Collaborative Ocular Melanoma Study (COMS), eye-sparing treatments have come to the fore today. External radiotherapy techniques (proton beam radiotherapy and stereotactic radiosurgery/fractionated stereotactic radiosurgery) are an important treatment option for globe-sparing treatments. There are no prospective randomized trials comparing these techniques; however, retrospective series, meta-analyses, and reviews indicate that these EPB and external radiotherapy techniques are equal. With this review, we aimed to examine the external radiotherapy techniques used in the treatment of uveal melanoma in detail with reference to the current literature.

Purpose We aimed to evaluate the prognostic factors and the role of stereotactic radiotherapy (SRT) as a re-irradiation technique in the management of progressive glioblastoma. Methods The records of 77 previously irradiated glioblastoma patients who progressed and received second course hypofractionated SRT (1–5 fractions) between 2009 and 2022 in our department were evaluated retrospectively. Statistical Package for the Social Sciences (SPSS) version 23.0 (IBM, Armonk, NY, USA) was utilized for all statistical analyses. Results The median time to progression from the end of initial radiotherapy was 14 months (range, 6–68 months). The most common SRT schedule was 30 Gy (range, 18–50 Gy) in 5 fractions (range, 1–5 fractions). The median follow-up after SRT was 9 months (range, 3–80 months). One-year overall (OS) and progression-free survival (PFS) rates after SRT were 46% and 35%, respectively. Re-irradiation dose and the presence of pseudoprogression were both significant independent positive prognostic factors for both OS ( p = 0.009 and p = 0.04, respectively) and PFS ( p = 0.008 and p = 0.04, respectively). For PFS, progression-free interval > 14 months was also a prognostic factor ( p = 0.04). The treatment was well tolerated without significant acute toxicity. During follow-up, radiation necrosis was observed in 17 patients (22%), and 14 (82%) of them were asymptomatic. Conclusion Hypofractionated SRT is an effective treatment approach for patients with progressive glioblastoma. Younger patients who progressed later than 14 months, received higher SRT doses, and experienced pseudoprogression following SRT had improved survival rates.

OBJECTIVE Radiation dermatitis is one of the most common radiotherapy-related side effects. There is no gold standard treatment for this side effect, which drastically affects patients' quality of life. Nevertheless, patients often use over-the-counter products. Hypericum perforatum (St. John's wort) is one of the most commonly used homemade remedies. In this work, we investigated whether Hypericum perforatum oil augments radiation sensitivity in a rat radiodermatitis model. METHODS Radiation dermatitis was induced in 16 male Sprague-Dawley rats by administration of single fraction 30 Gy external radiotherapy. Rats were randomly assigned to control and Hypericum perforatum oil-treated arms. Starting on the third day before and up to 14 days after radiotherapy, the Hypericum perforatum oil arm was treated with 100 mu l of Hypericum perforatum oil 3 times a day. Rats were observed for two weeks to assess acute skin changes, and irradiated rat skin samples were examined histomorphologically by scoring the presence of scarring, the severity of inflammation, and the extent of inflammation. RESULTS More skin reactions were observed in the Hypericum perforatum-treated-treated arm. In the histomorphological examination, the Hypericum perforatum oil-treated arm had higher scores than the control arm in terms of the presence of scarring, the severity of inflammation, and the extent of inflammation. CONCLUSION Our results showed that Hypericum perforatum oil exacerbated radiation dermatitis, and caution should be exercised while recommending it.

Background Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) recommendations are commonly used guidelines for adjuvant radiotherapy in glioblastoma. In our institutional protocol, we delineate T2-FLAIR alterations as gross target volume (GTV) with reduced clinical target volume (CTV) margins. We aimed to present our oncologic outcomes and compare the recurrence patterns and planning parameters with EORTC and RTOG delineation strategies. Methods Eighty-one patients who received CRT between 2014 and 2021 were evaluated retrospectively. EORTC and RTOG delineations performed on the simulation computed tomography and recurrence patterns and planning parameters were compared between delineation strategies. Statistical Package for the Social Sciences (SPSS) version 23.0 (IBM, Armonk, NY, USA) was utilized for statistical analyses. Results Median overall survival and progression-free survival were 21 months and 11 months, respectively. At a median 18 month follow-up, of the 48 patients for whom recurrence pattern analysis was performed, recurrence was encompassed by only our institutional protocol’s CTV in 13 (27%) of them. For the remaining 35 (73%) patients, recurrence was encompassed by all separate CTVs. In addition to the 100% rate of in-field recurrence, the smallest CTV and lower OAR doses were obtained by our protocol. Conclusions The current study provides promising results for including the T2-FLAIR alterations to the GTV with smaller CTV margins with impressive survival outcomes without any marginal recurrence. The fact that our protocol did not result in larger irradiated brain volume is further encouraging in terms of toxicity.

Background. Optic nerve sheath meningiomas (ONSM) are rare tumors potentially causing visual deficits. This study aims to report the anatomic and visual outcomes of patients with primary ONSM treated with hypofractionated stereotactic radiotherapy (HF-SRT).Methods. Data of 36 patients treated with HF-SRT between 2008 and 2019 were retrospectively collected. The clinical target volume (CTV) was equal to the gross tumor volume and a 2 mm was added for the planning target volume. All responses other than progression were accepted as local control (LC). The VA grading was performed under 3 groups to provide an even distribution; 20/400 or worse, 20/40-20/400, and 20/40 or better.Results. Median HF-SRT dose was 25 Gy and the median CTV was 1.94 cc. After a median of 106 months of follow-up, the tumor regressed in 23 (64%), was stable in 9 (25%), and progressed in 4 (11%) eyes. The overall rate of LC was 89% with 2-, 5-, 10-, and 15-year rate of 100%, 94%, 84%, and 84%, respectively. Treatment-related late toxicity rate was 11%. The VA was stable in 27 (75%) eyes, improved in 5 (14%) eyes, and worsened in 4 (11%) eyes, respectively, after HF-SRT. Female gender was the only independent predictor of an improved VA.Conclusions. Hypofractionated stereotactic radiotherapy is a safe and satisfactory treatment option for primary ONSM without severe toxicity. It may be advisable to commence treatment before an established visual deficit of 20/400 or worse occurs, to make the most of the functional benefit.

Background Stereotactic body radiotherapy (SBRT) allows the delivery of an ablative radiation dose to the tumor with minimal toxicity. Although magnetic resonance imaging (MRI)-guided SBRT appears to be a promising approach in the modern era, X-ray image-guided SBRT is still used worldwide for pancreatic cancer. This study aims to evaluate the results of X-ray image-guided SBRT in patients with locally advanced pancreatic cancer (LAPC).Methodology Medical records of 24 patients with unresectable LAPC who underwent X-ray image-guided SBRT between 2009 and 2022 were retrospectively evaluated. SPSS version 23.0 (IBM Corp., Armonk, NY, USA) was utilized for all analyses.Results The median age was 64 years (range = 42-81 years), and the median tumor size was 3.5 cm (range = 2.7-4 cm). The median total dose of SBRT was 35 Gy (range = 33-50 Gy) in five fractions. After SBRT, 30% of patients showed complete and 41% showed partial response, whereas 20% had stable disease and 9% had progression. Median follow-up was 15 months (range = 6-58 months). During follow-up, four (16%) patients had local recurrence, one (4%) had a regional recurrence, and 17 (70%) had distant metastasis (DM). The two-year local control (LC), local recurrence-free survival (LRFS), overall survival (OS), and DM-free survival (DMFS) rate was 87%, 36%, 37%, and 29%, respectively. In univariate analysis, a larger tumor size (>3.5 cm) and higher cancer antigen 19-9 level (>106.5 kU/L) significantly decreased the OS, LRFS, and DMFS rates. No severe acute toxicity was observed. However, two patients had severe late toxicity as intestinal bleeding.Conclusions X-ray image-guided SBRT provides a good LC rate with minimal toxicity for unresectable LAPC. However, despite modern systemic treatments, the rate of DM remains high which plays a major role in survival.

This study aims to dosimetrically compare multi-leaf collimator (MLC)-based and cone-based 3D LATTICE radiotherapy (LRT) plans. Valley-peak ratios were evaluated using seven different 3D LATTICE designs. Target volumes of 8 cm and 12 cm were defined on the RANDO phantom. Valley-peak dose patterns were obtained by creating high-dose vertices in the target volumes. By changing the vertex diameter, vertices separation, and volume ratio, seven different LATTICE designs were generated. Treatment plans were implemented using CyberKnife and Varian RapidArc. Thermoluminescent dosimeter (TLD), EBT3 films, and electronic portal-imaging device (EPID) were employed for dosimetric treatment verification, and measured doses were compared to calculated doses. By changing the vertex diameter and vertices separation, the valley-peak ratio was exhibited little difference between the two systems. By changing the vertex diameter and volume ratio, the valley-peak ratio was observed nearly the same for the two systems. The film, TLD, and EPID dosimetry showed good agreement between the calculated and measured doses. Based on the results, we concluded that although smaller valley-peak ratios were obtained with cone-based plans, the dose-volume histograms were comparable in both systems. Also, when we evaluated the treatment duration, the MLC-based plans were more appropriate to apply the treatment in a single fraction.

OBJECTIVEBrain metastases (BM) are a serious cause of morbidity and mortality in patients with solid tumors. Due to improvements in local and systemic therapies, there is a need for novel prognostic factors. Herein, we aimed to evaluate the oncological results and current prognostic factors for BM in patients with breast and lung cancer, receiving cranial radiotherapy (RT).METHODSMedical records of 147 patients who were diagnosed with lung or breast cancer and underwent cranial RT at our clinic between 2011 and 2021 were evaluated retrospectively.RESULTSThe median follow-up was 15 months (3-90 months). Local control rates for irradiated BM were 80% and 76% in patients receiving stereotactic RT and whole brain RT, respectively. Leptomeningeal metastasis (LM) developed in 24 patients (16%) during follow-up and, 87.5% of them had an infratentorial lesion. The 1-and 2-year overall survival (OS) and, intracranial progression-free survival rates were 57% and 36%, 30%, and 17%, respectively. Low-and intermediate-risk BM-velocity (BMV) is associated with better OS. None of the patients experienced severe (& GE;grade 3) acute toxicity.CONCLUSIONPrimary tumor histology, number, and localization of BM, treatment modality, extracranial disease status, development of radionecrosis, LM during follow-up, and BMV are important prognostic factors on survival in BM of patients diagnosed with lung and breast cancer. In the age of precision medicine, it is more crucial than ever to define and validate novel prognostic factors. Our findings contribute to justifying the addition of radionecrosis and BMV to predictive models.

Background and purpose: To report the long-term results of stereotactic radiosurgery and fractionated stereotactic radiation therapy (SRS/FSRT) in patients with uveal melanoma (UM). Materials and methods: We retrospectively evaluated the results of patients treated between 2007 and 2019. The primary endpoints were local control (LC), local recurrence-free survival (LRFS), enucleation-free survival (EFS) and treatment toxicity. Results: 443 patients with 445 UMs were treated via CyberKnife (R). According to the COMS classification, 70% of the tumors were small/medium and 30% were large. Median total RT dose was 54 Gy, median BED10 was 151 Gy. After a median 74-months follow-up, SRS/FSRT yielded an 83% overall LC rate. The 5-and 10-year LRFS rate was 74% and 56%, respectively. Patient age and the COMS size were prognostic for all survival endpoints. An increased SRS/FSRT dose was associated with higher LRFS and EFS rates. SRS/FSRT-related toxicity was observed in 49% of the eyes. Median visual acuity (VA) significantly deteriorated after SRS/FSRT in 76% of the treated eyes. The overall eye preservation rate was 62%, and the 5 -and 10-year EFS rate was 64% and 36%, respectively. The delivery of FSRT every other day resulted in a significantly lower rate of toxicity and enucleation compared to FSRT on consecutive days. Conclusion: A total dose of >= 45 Gy and BED10Gy >= 112.5 SRS/FSRT is associated with a higher LC rate in patients with UM. Despite the favorable outcomes, treatment toxicity is the major limitation of this treatment. Toxicity and enucleation can be minimized by treating the eye every other day. (C) 2022 Elsevier B.V. All rights reserved.

Patients receiving stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) may have an anxiety due to unknown aspects of the treatment. We aimed to reduce patient anxiety by using video-based education. Forty patients were divided into 2 groups, with one-to-one information session (n = 20) and one-to-one information session plus video-based education (n = 20). The patients completed the State-Trait Anxiety Inventory (STAI) and visual facial anxiety scale before and after information sessions and after treatment. The setup time and disruptions during treatment sessions were recorded for patients receiving treatment with Novalis® and Cyberknife®, respectively. The patient characteristics and STAI scores before education were similar between groups. The anxiety level was significantly lower in group 1 after treatment (median 38, interquartile range (IQR) 27–45) compared to before (median 43, IQR 36–47) (p = 0.003) and after information sessions (median 42, IQR 36–47) (p = 0.004); however, any difference was not observed in anxiety levels between before and after information sessions (p = 0.317). The anxiety level was significantly lower in group 2 after video-based education (median 25, IQR 22–33) and after treatment (median 25, IQR 20–30) compared to before video-based education (median 35, IQR 31–42) (p < 0.001 for both), while there was no significant difference in anxiety levels between after video-based education and after the treatment (p = 0.407). The interruptions during treatment were observed in 9 (60

Background Radiotherapy (RT) with immune checkpoint inhibitors (ICI) has yielded good responses in many cancers. We aimed to report the results of combined fractionated stereotactic radiotherapy (FSRT) and ICI in patients with recurrent high-grade glioma. Methodology Patients were treated with FSRT and nivolumab which were continued until progression or toxicity. The Response Assessment in Neuro-oncology and Immunotherapy Response Assessment in Neuro-oncology criteria were used to assess treatment response on magnetic resonance imaging. Treatment-related toxicity was noted in all patients. Results A total of eight patients were included. Recurrence was detected after a median of 5.8 months following the first RT, all in the treatment field. FSRT (3 × 8 Gy) was applied with neoadjuvant, concurrent, and adjuvant nivolumab. After a median follow-up of 21.3 months from diagnosis and 12.6 months from recurrence, one patient was alive and seven succumbed to the disease. The median overall survival was 20.9 months after diagnosis and 12.9 months after recurrence. The median progression-free interval was 2.3 months after FSRT. The local control (LC) rate was 62.5% with a median local recurrence-free survival of nine months. Progression in other regions of the brain was observed in four patients with a median progression-free survival of 2.1 months. Acute toxicity was not observed. ICI-related grade 3 late pneumonitis was observed in two patients, and grade 1 late thyroid toxicity in two patients. One patient with pneumonitis also developed osteoporosis and radiation necrosis. Conclusions A high LC rate was achieved with concurrent FSRT and ICI with a severe late toxicity rate of 25%. This combination can be an option in recurrent high-grade gliomas.

Neoadjuvant chemoradiotherapy (CRT) followed by surgical resection is the standard treatment for locally advanced rectal adenocarcinoma. In this study we evaluate our treatment results in patients treated with neoadjuvant radiotherapy (RT). Medical records of 144 patients treated between January 2009 and February 2019 were retrospectively evaluated. Most of the patients had (76%) MRI as a part of initial staging. Patients received either short course (25 Gy/5 fractions) (8%) or long course RT (92%) (median 50.4 Gy/28 fractions) +/- chemotherapy (ChT). Median age was 56 years (range, 24-90 years) and 131 patients received CRT. Most common concomitant ChT regime was oral capecitabine (48%). 26 patients refused the surgery. For rest of the patients, median time to surgery was 8 weeks. Sphincter was preserved in 19 patients (38%) who underwent surgery for distal tumors. With a median follow-up of 28 months, 19 patients had local recurrence and 30 patients had distant metastases. Two and five year estimated overall survival (OS), locoregional control (LRC) and distant metastases free survival (DMFS) rates were 88-67%, 78-62% and 74-57%, respectively. Presence of surgery significantly affect OS (HR= 0.147, 95% CI: 0.67-0.32, p< 0.001) , LRC (HR= 0.10, 95% CI: 0.05-0.2, p< 0.001) and DMFS (HR= 0.25, 95% CI: 0.13-0.49). Patients tolerated the treatment well with no grade 3 acute or late gastrointestinal and genitourinary system toxicities. Regardless of the schema neoadjuvant RT seems to be an efficient and safe treatment for patients with rectal adenocarcinoma. We found that surgery is the sole prognostic factor for better OS, LC and DMFS.

OBJECTIVE Epileptic seizures are prognostic for low-grade gliomas. However, the impact of anti-epileptic drug use (AED) on outcomes is unclear. We aimed to evaluate the impact of epileptic seizures and AED use on tumor control and survival rates after radiotherapy (RT) in patients with World Health Organization Grade II glioma. METHODS A total of 182 patients who underwent RT either early after surgery or in case of progression were retrospectively evaluated. The primary end point was the impact of seizures on overall survival (OS), local control (LC), and progression-free survival (PFS) rates. The secondary end point was the impact of AED use on these rates. RESULTS Median follow-up was 80 months. The number of patients with epileptic seizures at the time of diagnosis was 113 (62%). The 2-, 5-, and 10-year OS, LC, and PFS rates were significantly higher in patients with seizures (p=0.022 and p=0.001, respectively). When patients that did and did not use AED were compared, OS, LC, and PFS rates were similar. Besides, using AEDs in patients without seizures did not affect the OS, LC, and PFS rates. Carbamazepine use was associated with higher OS and PFS rates with a non-significant increase in LC. Phenytoin use yielded an increase in the PFS and LC rates in the first 2 years which turned to opposite after the 6th year. CONCLUSION Seizures at the time of diagnosis and using AEDs for the treatment of seizures both increase survival rates in patients with Grade II glioma. Patients using carbamazepine had increased survival rates.

To evaluate stereotactic radiosurgery/fractionated stereotactic radiosurgery (SRS/fSRS) treatment outcomes of recurrent glial tumor patients who were previously treated with surgery and radiotherapy and who were not candidate for re-surgery. Thirty-one recurrent glial tumor patients treated with Cyberknife (AccurayIncorporated, Sunnyvale, CA, USA) were prospectively evaluated. The endpoints of the study were overall survival after the first diagnosis, overall survival after re-irradiation, and the parameters that affect them. Acute and chronic side effects related to the treatment were recorded. The median time between first radiotherapy and reirradiation was 26 months (range, 4-232 months). After the first radiation treatment, 27 (%87) patients relapsed in the primary radiotherapy region. A median total dose of 30 Gy (range, 18-40 Gy) was delivered in median fractions of 5 (range, 1-5 fraction) with CyberKnife. The Median follow-up was 12 months (6-37 months). The median tumor volume was 13 cc (range, 6-100 cc). The median overall survival after reirradiation was 15 months (range, 6-33 months). All the patients who developed grade 4 radionecrosis had tumor volumes greater than 25 ml. In multivariate analysis, only tumor volume (>= 15 ml vs. < 15 ml) was found to be a statistically significant independent predictor for survival after reirradiation (p=0.015). Large irradiation volumes increase radionecrosis risk and decrease tumor control probability. SRS/fSRS is safe and may be an effective treatment option for selected recurrent high-grade glioma patients with small focal tumors.

Vitreous humor (VH) is not considered as a critical structure in the radiotherapy planning process. In the present study, an experimental animal model was performed to examine the effects of radiotherapy on VH. The right eyes of twelve New Zealand rabbits were irradiated to 60 Gy in 3 fractions in accordance with the scheme used in the treatment of uveal melanoma in our clinic, and contralateral (left) eyes were considered as control. Weekly ophthalmologic examination was performed after irradiation, for three months. At the end of the third month, enucleation and vitreous collection were conducted. The vitreous samples were subjected to metabolomic analyses, ELISA analyses, viscosity measurements, and electron microscopic examination. In control and experimental vitreous samples, 275 different metabolites were identified, and 34 were found to differ significantly between groups. In multivariate analyzes, a clear distinction was observed between control and irradiated vitreous samples. Pathway analysis revealed that nine pathways were affected, and these pathways were mainly related to amino acid metabolism. A significant decrease was observed in the expressions of type II, V, and XI collagens in protein level in the ELISA. There was a non-significant decrease in type IX collagen and viscosity. Electron microscopic examination revealed disrupted collagen fibrillar ultra-structure and dispersed collagen fragments in the experimental vitreous. An intact vitreous is essential for a healthy eye. In this study, we observed that radiation causes changes in the vitreous that may have long-term consequences.