The effect of photon energy on dose distribution in volumetric-modulated arc therapy planning for head and neck cancer

2020 ◽  
pp. 1-5
Author(s):  
Trang Hong Thi Nguyen ◽  
Akihiro Takemura ◽  
Shinichi Ueda ◽  
Kimiya Noto ◽  
Hironori Kojima ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Dose Distribution ◽  
Maximum Dose ◽  
Volumetric Modulated Arc Therapy ◽  
Dual Energy ◽  
Planning System ◽  
Treatment Planning System ◽  
Arc Therapy

Abstract Aim: To investigate the effect of different energies on dose distribution in volumetric-modulated arc therapy (VMAT) plans for head and neck cancer. Materials and methods: Data from nine patients undergoing VMAT plans using 6 MV, 10 MV and dual-energy X-ray beams with the Pinnacle 3 V 9.10 treatment planning system (Philips Medical System, Fitchburg, WI, USA) were analysed for quality using the conformity index (CI) and homogeneity index (HI) for planning target volume (PTV), and for mean and maximum dose to the organs at risk (OARs): parotid glands, brainstem, spinal cord and optic nerves. Results: There were no clear differences in the HIs of the PTV dose among the different plans. The CIs for 10 MV and dual-energy VMAT plans were superior to that of the 6 MV VMAT plan (0·8 ± 0·3, 0·8 ± 0·3, and 0·7 ± 0·2, respectively; p = 0·001). There were no significant differences in mean/maximum dose to the OARs among the three VMAT plans. Findings: Compared with the 6 MV VMAT plan, the dual-energy VMAT plan slightly increased the coverage of the PTV with the prescribed dose but did not decrease dose to the OARs.

A hybrid approach for head and neck cancer using online image guidance and offline adaptive radiotherapy planning

2019 ◽  
Vol 18 (03) ◽  
pp. 271-275 ◽  
Author(s):  
Roopam Srivastava ◽  
P.K. Sharma ◽  
K.J. Maria Das ◽  
Jayanand Manjhi
Keyword(s):  
Computed Tomography ◽  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Dose Distribution ◽  
Treatment Plan ◽  
Planning System ◽  
Radiotherapy Planning ◽  
Treatment Planning System ◽  
Medical Systems

AbstractBackgroundThis is a prospective study to evaluate the dosimetric benefits of treatment plan adaptation for patients who had undergone repeat computed tomography (ReCT)and re-planning due to treatment-induced anatomical changes during radiotherapy.Materials and MethodsThis study involved five head and neck cancer patients who had their treatment plan modified, based on weekly thrice imaging protocol. Impact of mid-course imaging was assessed in patients using ReCT and cone beam computed tomography (CBCT)-based dose verification. Patients were imaged, apart from their initial CT, during the course of their radiation therapy with a ReCT and on board imager CBCT (Varian Medical Systems Inc., Palo Alto, CA, USA). Each CBCT/CT series was rigidly registered to the initial CT in the treatment planning system Eclipse (Varian Medical Systems Inc.) using bony landmarks. The structures were copied to the current CBCT/CT series and, where needed, manually edited slicewise. The dose distribution from the treatment plan was viewed as of the current anatomy by applying the treatment plan the CBCT/CT series, and studying the corresponding dose–volume histograms for organs at risk doses.ResultsThe reduction of parotid volumes due to weight loss was observed in all patients, which means an increase in predicted mean doses of parotid when initial CT plan was re-calculated on ReCT and CBCT (Table 1). This explains the necessity of adaptive planning. The predicted mean dose of parotid glands was increased and constraints to spinal cord and skin were exceeded, so re-planning was performed.ConclusionsThe CBCT is a useful tool to view anatomic changes in patients and get an estimate of their impact on dose distribution. Re-planning based on imaging in head and neck patients during the course of radiotherapy is mandatory to reduce side effects.

Quality assurance of volumetric-modulated arc therapy head and neck cancer treatment using PRESAGE® dosimeter

2018 ◽  
Vol 17 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Jalil ur Rehman ◽  
Muhammad Isa ◽  
Nisar Ahmad ◽  
H. M. Noor ul Huda Khan Asghar ◽  
Zaheer A. Gilani ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Cancer Treatment ◽  
Head And Neck ◽  
Treatment Planning ◽  
Volumetric Modulated Arc Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Ct Scans ◽  
Arc Therapy ◽  
Calculated Dose

AbstractBackgroundAccurate three-dimensional dosimetry is essential in modern radiotherapy techniques such as volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). In this research work, the PRESAGE® dosimeter was used as quality assurance (QA) tool for VMAT planning for head and neck (H&N) cancer.Material and methodComputer tomography (CT) scans of an Image Radiation Oncology Core (IROC) H&N anthropomorphic phantom with both IROC standard insert and PRESAGE® insert were acquired separately. Both CT scans were imported into the Pinnacle (9.4 version) TPS for treatment planning, where the structures [planning target volume (PTV), organs at risk) and thermoluminescent detectors (TLDs) were manually contoured and used to optimise a VMAT plan. Treatment planning was done using VMAT (dual arc: 182°–178°, 178°–182°). Beam profile comparisons and gamma analysis were used to quantify agreement with film, PRESAGE® measurement and treatment planning system (TPS) calculated dose distribution.ResultsThe average ratio of TLD measured to calculated doses at the four PTV locations in the H&N phantom were between 0·95 to 0·99 for all three VMAT deliveries. Dose profiles were taken along the left–right, the anterior–posterior and superior–inferior axes, and good agreement was found between the PRESAGE® and Pinnacle profile. The mean value of gamma results for three VMAT deliveries in axial and sagittal planes were found to be 94·24 and 93·16% when compared with film and Pinnacle, respectively. The average values comparing the PRESAGE® results and dose values calculated on Pinnacle were observed to be 95·29 and 94·38% in the said planes, respectively, using a 5%/3 mm gamma criteria.ConclusionThe PRESAGE® dose measurements and calculated dose of pinnacle show reasonable agreement in both axial and sagittal planes for complex dual arc VMAT treatment plans. In general, the PRESAGE® dosimeter is found to be a feasible QA tool of VMAT plan for H&N cancer treatment.

scholarly journals Is volumetric modulated arc therapy with constant dose rate a valid option in radiation therapy for head and neck cancer patients?

2018 ◽  
Vol 23 (3) ◽  
pp. 175-182 ◽  
Author(s):  
Annamaria Didona ◽  
Valentina Lancellotta ◽  
Claudio Zucchetti ◽  
Bianca Moira Panizza ◽  
Alessandro Frattegiani ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Head And Neck Cancer ◽  
Head And Neck ◽  
Dose Rate ◽  
Cancer Patients ◽  
Neck Cancer ◽  
Volumetric Modulated Arc Therapy ◽  
Arc Therapy ◽  
Constant Dose ◽  
Constant Dose Rate

Impact of setup error on integral dose in head and neck cancer treated with intensity modulated radiation therapy

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e17056-e17056
Author(s):  
R. V. Prabhakar ◽  
K. P. Haresh ◽  
M. A. Laviraj ◽  
G. K. Rath ◽  
P. K. Julka
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Tissue ◽  
Setup Error ◽  
Integral Dose ◽  
Posterior Direction

e17056 Background: Intensity modulated radiation therapy (IMRT) has been widely used in the treatment of head and neck cancer and has the potential of escalating the dose with less morbidity. Integral dose is a concern in radiotherapy especially with IMRT as it may lead to an increase in second malignancies. Setup error is another important issue in radiotherapy which affects the final treatment outcome. In this study, the effect of setup error on non-target integral dose (NTID) for head and neck cancer treated with IMRT has been studied. Methods: Twelve patients of carcinoma of nasopharynx treated by IMRT with simultaneous integrated boost technique were included. The dose to the gross tumor volume (PTV70), CTV1 (PTV59.4) and CTV2 (PTV54) were planned for 70 Gy, 59.4 Gy and 54 Gy respectively in 33 fractions. All the patients were planned with nine equally spaced beams. The IMRT plan was generated in Eclipse treatment planning system using sliding window technique. Keeping it as the base plan, the patient setup error was simulated in the treatment planning system for 3 mm, 5 mm and 10 mm by shifting the isocenter in all three dimensions viz. anterior, posterior, superior, inferior, right lateral and left lateral. NTID was calculated from the following relation NTID = (non-target tissue volume X mean non-target tissue dose)/1000. Paired sample t-test was performed to compare NTID for different shifts with no shift (statistical significance: p < 0.05). Results: The mean NTID for no shift was 120.75 ± 22.85 (median: 116.59). The mean NTID with isocenter shift along the anterior direction were 119.87 ± 22.80, 119.24 ± 22.80, 117.97 ± 22.52 for 3 mm, 5 mm and 10 mm respectively. Similarly, the NTID for the posterior shifts were 121.59 ± 22.96, 122.08 ± 23.07 and 123.26 ± 23.34 for 3 mm, 5 mm and 10 mm respectively. The anterior and posterior setup error showed statistically significant difference (p < 0.0001) for NTID compared to no shift whereas lateral, superior and inferior setup errors were found to be statistically insignificant. Conclusions: Setup error is an important issue in radiotherapy. Our study shows that setup error along the posterior direction significantly increases NTID. Hence, the setup error along the posterior direction may increase the risk of second malignances in IMRT. No significant financial relationships to disclose.

Sign in / Sign up

Export Citation Format

Share Document