scholarly journals Deterioration of Intended Target Volume Radiation Dose Due to Anatomical Changes in Patients with Head-and-Neck Cancer

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4253
Author(s):  
Olga Hamming-Vrieze ◽  
Simon van Kranen ◽  
Iris Walraven ◽  
Arash Navran ◽  
Abrahim Al-Mamgani ◽  
...  

Delivered radiation dose can differ from intended dose. This study quantifies dose deterioration in targets, identifies predictive factors, and compares dosimetric to clinical patient selection for adaptive radiotherapy in head-and-neck cancer patients. One hundred and eighty-eight consecutive head-and-neck cancer patients treated up to 70 Gy were analyzed. Daily delivered dose was calculated, accumulated, and compared to the planned dose. Cutoff values (1 Gy/2 Gy) were used to assess plan deterioration in the highest/lowest dose percentile (D1/D99). Differences in clinical factors between patients with/without dosimetric deterioration were statistically tested. Dosimetric deterioration was evaluated in clinically selected patients for adaptive radiotherapy with CBCT. Respectively, 16% and 4% of patients had deterioration over 1 Gy in D99 and D1 in any of the targets, this was 5% (D99) and 2% (D1) over 2 Gy. Factors associated with deterioration of D99 were higher baseline weight/BMI, weight gain early in treatment, and smaller PTV margins. The sensitivity of visual patient selection with CBCT was 22% for detection of dosimetric changes over 1 Gy. Large dose deteriorations in targets occur in a minority of patients. Clinical prediction based on patient characteristics or CBCT is challenging and dosimetric selection tools seem warranted to identify patients in need for ART, especially in treatment with small PTV margins.

2014 ◽  
Vol 41 (6Part29) ◽  
pp. 505-506
Author(s):  
H Gay ◽  
J Oh ◽  
A Apte ◽  
P Dyk ◽  
D Mullen ◽  
...  

2021 ◽  
Vol 9 (3) ◽  
pp. 167-171
Author(s):  
Dr. Aparajeeta Aparajeeta ◽  
◽  
Dr. Ankita Mehta ◽  
Mr. N.S. Silambarasan ◽  
Dr. Piyush Kumar ◽  
...  

Background: The increasing patient load in radiotherapy centres demands selection of thetechnique that provides plans with optimal dosimetry in terms of target volume coverage, organs atrisk (OAR) sparing and a lesser treatment time. This study was designed to compare the two widelypractised conformal techniques, IMRT and VMAT in head and neck cancer patients in terms ofplanning target volume (PTV) coverage, OAR sparing and treatment delivery parameters. Materialsand methods: For ten postoperative head and neck cancer patients who had been treated by IMRTtechnique virtual VMAT plans were generated for study purposes. The dose prescribed to PTV was 60Gy in 30 fractions. The dose-volume parameters of PTV and OARs and the treatment deliveryparameters were compared amongst both the techniques. Statistical significance was calculatedusing paired ‘t’ test. Results: Both the plans were comparable in terms of dosimetry. The onlysignificant difference being better conformity in the IMRT plans. The dose to OARs was alsocomparable in both the techniques except for a significant reduction in the point dose to brainstemwith the IMRT technique. Given the treatment delivery parameters, there was a significant reductionin the treatment delivery time and monitor units with the VMAT technique compared to the IMRTtechnique. Conclusion: VMAT technique gave comparable plans to that of the IMRT technique interms of dosimetry but reduced the treatment time. It seems feasible in radiotherapy centres withincreased patient load.


2021 ◽  
Vol 161 ◽  
pp. S1680-S1681
Author(s):  
Y.A.C. FIAGAN ◽  
D. Nevens ◽  
E. Bossuyt ◽  
M. Machiels ◽  
I. Chiairi ◽  
...  

2011 ◽  
Vol 99 ◽  
pp. S447
Author(s):  
Senkesen ◽  
E. Tezcanli ◽  
E. Goksel ◽  
M. Garipagaoglu ◽  
M. Sengoz ◽  
...  

2018 ◽  
Vol 159 (29) ◽  
pp. 1193-1200
Author(s):  
Péter Kovács ◽  
Evelin Szita ◽  
Kitti Schvarcz ◽  
Szabolcs Kamu ◽  
Judit Kalincsák ◽  
...  

Abstract: Introduction: Image-guided intensity-modulated radiation therapy is essential for oncology treatment of head-and-neck cancer patients. Aim: MV-kV and CBCT modalities were compared in case of IGRT treatment for head-and-neck cancer patients. Setup error, setup margin (SM), imaging and evaluation times and imaging doses were analyzed. Method: Eight patients’ elective treatment was evaluated, 66 orthogonal MV-kV images and 66 CBCT series were acquired. Setup error measurement was based on bony manual image registration in three translational directions. Normality test and F-test were performed followed by the comparison with independent-samples T-test (p<0,05). The necessary target volume setup margin was calculated based on Van Herk’s equation. Imaging time and setup error determination time were measured. Imaging doses were estimated based on the literature. Results: No statistically significant difference was found between setup errors determined by MV-kV and CBCT (VRT: 0.5 mm, SD = 1.9 vs. 0.4 mm, SD = 2.1, p = 0.371; LNG: 0.2 mm, SD = 2.2 vs. –0.1 mm, SD = 2.2, p = 0.188; LAT: 0.2 mm, SD = 2.2 vs. 0.3 mm, SD = 2.1, p = 0.41). SM values were: VRT: 2.7 mm vs. 2.5 mm; LNG: 2.1 mm vs. 1.3 mm; LAT: 2.2 mm vs. 2.3 mm. Mean imaging time was 0.65 min (MV-kV) vs. 2.29 min (CBCT). Mean setup error determination time was 2.41 min for both modalities. Estimated imaging doses were 6.88 mGy (MV-kV) vs. 17.2 mGy (CBCT) per fraction. Conclusion: The bony anatomy derived image registration based translational setup error determination results in similar values either by MV-kV or by CBCT. Using 3 mm setup margin in all the directions might be adequate. Imaging time is less by MV-kV, significant difference in imaging doses did not appear. Using CBCT is generally suggested. MV-kV might be an alternative in case of need for shortened imaging time. Orv Hetil. 2018; 159(29): 1193–1200.


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