Acute radiation reactions in oral and pharyngeal mucosa: tolerable levels in altered fractionation schedules

Objective: To assess the image quality and dosimetric effects of the Philips orthopaedic metal artefact reduction (OMAR) (Philips Healthcare System, Cleveland, OH) function for reducing metal artefacts on CT images of head and neck (H&N) patients. Methods: 11 patients and a custom-built phantom with metal bead inserts (alumina, titanium, zirconia and chrome) were scanned. The image was reconstructed in two ways: with and without OMAR (OMAR and non-OMAR image). The mean and standard deviation values of CT Hounsfield unit (HU) for selected regions of interest of each case were investigated for both images. Volumetric modulated arc therapy plans were generated for all cases. Gamma analysis of each dose distribution pair in the patient (1%/1 mm criteria) and phantom (2%/2 mm and 3%/3 mm criteria) images was performed. The film measurements in phantom for two metal beads were conducted for evaluating the calculated dose on both OMAR and non-OMAR images.Results: In the OMAR images, noise values were generally reduced, and the mean HU became closer to the reference value (measured from patients without metal implants) in both patient and phantom cases. Although dosimetric difference was insignificant for the eight closed-mouth patients (g 5 99.4 60.5%), there was a large discrepancy in dosimetric calculation between OMAR and non-OMAR images for the three opened-mouth patients (g 5 91.1%, 94.8% and 96.6%). Moreover, the calculated dose on the OMAR image is closer to the real delivered dose on a radiochromic film than was the dose from the non-OMAR image. Conclusion: The OMAR algorithm increases the accuracy of CT HU and reduces the noise such that the entire radiation treatment planning process can be improved, especially for contouring and segmentation. Advances in knowledge: OMAR reconstruction is appropriate for the radiotherapy planning process of H&N patients, particularly of patients who use a bite block.Over the duration of several surgeries and treatments, metallic objects such as orthopaedic implants, surgical staples and clips, radioisotope seeds or dental implants may be inserted into the patient's body. Owing to the high Z of these materials, metal streak artefacts in the CT image can be induced through the combination of beam hardening, scatter, photon starvation, partial volume effects and aliasing.

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“…The difference between planned dose and delivered dose on the mucosa may cause issues with underdosing. 38 …”

Section: Discussionmentioning

confidence: 99%

Evaluation of a commercial orthopaedic metal artefact reduction tool in radiation therapy of patients with head and neck cancer

Kwon

Kim

Chun³

et al. 2015

BJR

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“…Acute toxicity, such as mucositis and pain, has been associated with deteriorating functional outcomes known to impact on swallowing and mastication (9), resulting in a large proportion of patients requiring modified diets and nutritional supplementation (10,11).…”

Section: Introductionmentioning

confidence: 99%

Long-term Functional Outcomes and Patient Perspective Following Altered Fractionation Radiotherapy with Concomitant Boost for Oropharyngeal Cancer

et al. 2012

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“…NTCP was calculated using Lyman's model [8] and tolerance parameters according to Emami et al [9] were applied ( Table 2). The risk of acute mucositis was assessed according to Fowler's model based on analysis of clinical data about acute mucosal reactions from clinical trials with altered fracionation [10]. For TCP calculation we used a model based on Poisson statistics incorporating the parameters of a linear quadratic model [11].…”

Section: Methodsmentioning

confidence: 99%

High dose rate versus low dose rate brachytherapy in the treatment of tongue carcinoma – a radiobiological study

Petera

Matula²,

Paluska³

et al. 2009

neo

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low dose rate (ldr) brachytherapy is a well established treatment for the early stages of tongue cancer. High dose rate (Hdr) afterloading devices have replaced ldr brachytherapy in many radiotherapy departments, but the effect and safety of Hdr brachytherapy in comparison with ldr brachytherapy for interstitial applications is an unresolved question. the aim of our radiobiological study was to utilize dose volume histiograms from patients treated in our institution to simulate the risk of complication of ldr and Hdr brachytherapy. normal tissue complication probabilities (ntcP) of acute mucositis, late mucosal necrosis and osteoradionecrosis of two Hdr brachytherapy schedules (18 x 3 gy bid and 10 x 6 gy bid) and of ldr brachytherapy with identical tumor control probability were compared using data from 8 brachytherapy applications. a linear quadratic (lQ) model was used to calculate the biologically equivalent doses, the effective volume method of kutcher and Burman and lyman's model was used to calculate ntcP. the student's two-tailed test was used for statistical analysis. For 18 x 3 gy bid the risk of acute mucositis and of late mucosal necrosis was 1.48 and 1.66 times higher with Hdr in comparison with ldr brachytherapy. For 10 x 6 gy bid the risk of acute mucositis, mucosal necrosis and osteoradionecrosis was 1.3, 3.44 and 13.18 times higher with Hdr brachytherapy. all differences were statistically highly significant. our radiobiological study supported the hypothesis that Hdr has a higher risk of complication in comparison with ldr brachytherapy for the same tumor control probability.

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Acute radiation reactions in oral and pharyngeal mucosa: tolerable levels in altered fractionation schedules

Cited by 123 publications

References 32 publications

Evaluation of a commercial orthopaedic metal artefact reduction tool in radiation therapy of patients with head and neck cancer

Evaluation of a commercial orthopaedic metal artefact reduction tool in radiation therapy of patients with head and neck cancer

Long-term Functional Outcomes and Patient Perspective Following Altered Fractionation Radiotherapy with Concomitant Boost for Oropharyngeal Cancer

High dose rate versus low dose rate brachytherapy in the treatment of tongue carcinoma – a radiobiological study

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