Is IMAT the ultimate evolution of conformal radiotherapy? Dosimetric comparison of helical tomotherapy and volumetric modulated arc therapy for oropharyngeal cancer in a planning study

Vernat, S. Servagi; Ali, David; Puyraveau, Marc; Viard, R.; Lisbona, A.; Fénoglietto, P.; Bedos, L.; Makovicka, Libor; Giraud, P.

doi:10.1016/j.ejmp.2013.07.128

Cited by 20 publications

(9 citation statements)

References 16 publications

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“…In this respect, normal-tissue integral dose is a burning issue with HT and represents a classical disadvantage of this technique. Indeed, as we reported here, several data suggest that HT increases NTID and healthy tissue volumes irradiated with low dose radiation compared to VMAT [ 31 , 35 ], with an undetermined risk of second cancer. Nevertheless, a few data suggest that new dynamic jaws HTs could now decrease the integral dose compared to regular HTs [ 36 ].…”

Section: Discussionsupporting

confidence: 67%

“…They also found that for high risk PTV (but not for low risk PTV), HT provided poorer conformity index than VMAT RapidArc® (defined as our healthy tissue conformity index), that quite agrees with our results [ 33 ]. In another study, VMAT RapidArc® was surprisingly globally better in terms of homogeneity index for low risk and intermediate risk PTV and DSC for intermediate and high risk PTV [ 31 ].…”

Section: Discussionmentioning

confidence: 99%

“… Dose homogeneity: The ideal value of HI is 0. For healthy tissue, we defined integral dose (ID) to the non tumor-tissue volume (NTID) as follows [ 30 , 31 ]: where: …”

Section: Methodsmentioning

confidence: 99%

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Dosimetric comparison between helical tomotherapy and volumetric modulated arc-therapy for non-anaplastic thyroid cancer treatment

et al. 2014

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BackgroundTo evaluate and compare dosimetric parameters of volumetric modulated arctherapy (VMAT) and helical tomotherapy (HT) for non-anaplastic thyroid cancer adjuvant radiotherapy.MethodsTwelve patients with non-anaplastic thyroid cancer at high risk of local relapse received adjuvant external beam radiotherapy with curative intent in our institution, using a two-dose level prescription with a simultaneous integrated boost approach. Each patient was re-planned by the same physicist twice using both VMAT and HT. Several dosimetric quality indexes were used: target coverage index (proportion of the target volume covered by the reference isodose), healthy tissue conformity index (proportion of the reference isodose volume including the target volume), conformation number (combining both previous indexes), Dice Similarity Coefficient (DSC), and homogeneity index ((D2%-D98%)/prescribed dose). Dose-volume histogram statistics were also compared.ResultsHT provided statistically better target coverage index and homogeneity index for low risk PTV in comparison with VMAT (respectively 0.99 vs. 0.97 (p = 0.008) and 0.22 vs. 0.25 (p = 0.016)). However, HT provided poorer results for healthy tissue conformity index, conformation number and DSC with low risk and high risk PTV. As regards organs at risk sparing, by comparison with VMAT, HT statistically decreased the D2% to medullary canal (25.3 Gy vs. 32.6 Gy (p = 0.003)). Besides, HT allowed a slight sparing dose for the controlateral parotid (Dmean: 4.3 Gy vs. 6.6 Gy (p = 0.032)) and for the controlateral sub-maxillary gland (Dmean: 29.1 Gy vs. 33.1 Gy (p = 0.041)).ConclusionsBoth VMAT and HT techniques for adjuvant treatment of non-anaplastic thyroid cancer provide globally attractive treatment plans with slight dosimetric differences. However, helical tomotherapy clearly provides a benefit in term of medullary canal sparing.

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

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Dosimetric comparison between helical tomotherapy and volumetric modulated arc-therapy for non-anaplastic thyroid cancer treatment

et al. 2014

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“…Further, HT also demonstrated a 2.0Gy and 2.3Gy decrease in Dmax of the ipsilateral and contralateral temporal lobes, respectively, despite their similar performance in V60Gy. The advantage of HT in central nervous system protection is supported by several previous studies on other HNCs [ 23 , 24 ]. In consideration of the incapacitating and devastating results of radiation-induced brainstem injury and temporal lobe necrosis, every possible measure should be taken to lower the dose to the central nervous system [ 18 , 35 , 36 ].…”

Section: Discussionmentioning

confidence: 57%

“…Many studies have demonstrated that both VMAT and HT can outperform conventional IMRT; comparisons between VMAT and HT are needed to inform the choice of treatment methods. There have been several studies comparing VMAT and HT in other HNCs, indicating that VMAT is better in shortening delivering time and protecting thyroid glands and optic nerves while HT is superior in dose conformity and sparing of lens and brain stem [ 4 , 22 – 24 ]. However, very few publications have focused on such comparisons in NPC.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric Comparisons of Volumetric Modulated Arc Therapy and Tomotherapy for Early T-Stage Nasopharyngeal Carcinoma

Zhou

Shen

et al. 2018

BioMed Research International

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Purpose To compare the dosimetric differences between volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) in treating early T-stage nasopharyngeal carcinoma (NPC). Method Ten patients with early T-stage NPC who received tomotherapy using simultaneously integrated boost (SIB) strategies were replanned with VMAT (RapidArc of Varian, dual-arc). Dosimetric comparisons between the RapidArc plan and the HT plan included the following: (1) D98, homogeneity, and conformity of PTVs; (2) sparing of organs at risk (OARs); (3) delivery time and monitor units (MUs). Results (1) Compared with RapidArc, HT achieved better dose conformity (CI of PGTVnx + nd: 0.861 versus 0.818, P = 0.004). (2) In terms of OAR protection, RapidArc exhibited significant superiority in sparing ipsilateral optic nerve (Dmax: 27.5Gy versus 49.1Gy, P < 0.001; D2: 23.5Gy versus 48.2Gy, P < 0.001), contralateral optic nerve (Dmax: 30.4Gy versus 49.2Gy, P < 0.001; D2: 26.2Gy versus 48.1Gy, P < 0.001), and optic chiasm (Dmax: 32.8Gy versus 48.3Gy, P < 0.001; D2: 30Gy versus 47.6Gy, P < 0.001). HT demonstrated a superior ability to protect the brain stem (D1cc: 43.0Gy versus 45.2Gy, P = 0.012), ipsilateral temporal lobe (Dmax 64.5Gy versus 66.4 Gy, P = 0.015), contralateral temporal lobe (Dmax: 62.8Gy versus 65.1Gy, P = 0.001), ipsilateral lens (Dmax: 4.27Gy versus 5.24Gy, P = 0.009; D2: 4.00Gy versus 5.05Gy, P = 0.002; Dmean: 2.99Gy versus 4.31Gy, P < 0.001), contralateral lens (Dmax: 4.25Gy versus 5.09Gy, P = 0.047; D2: 3.91Gy versus 4.92Gy, P = 0.005; Dmean: 2.91Gy versus 4.18Gy, P < 0.001), ipsilateral parotid (Dmean: 36.4Gy versus 41.1Gy, P = 0.002; V30Gy: 54.8% versus 70.4%, P = 0.009), and contralateral parotid (Dmean: 33.4Gy versus 39.1Gy, P < 0.001; V30Gy: 48.2% versus 67.3%, P = 0.005). There were no statistically significant differences in spinal cord or pituitary protection between the RapidArc plan and the HT plan. (3) RapidArc achieved a much shorter delivery time (3.8 min versus 7.5 min, P < 0.001) and a lower MU (618MUs versus 5646MUs, P < 0.001). Conclusion Our results show that RapidArc and HT are comparable in D98, dose homogeneity, and protection of the spinal cord and pituitary gland. RapidArc performs better in shortening delivery time, lowering MUs, and sparing the optic nerve and optic chiasm. HT is superior in dose conformity and protection of the brain stem, temporal lobe, lens, and parotid.

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Dosimetric comparison of tomotherapy and volumetric‐modulated arc therapy for children with neuroblastoma

Liu

Pang

et al. 2020

Pediatric Investigation

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Importance Irradiation treatment for pediatric patients with neuroblastoma represents a major challenge due to the pediatric dose limits for critical structures and the necessity of sufficient dose coverage of the clinical target volume for local control. Objective To investigate dosimetric differences between tomotherapy (TOMO) and volumetric‐modulated arc therapy (VMAT) as retroperitoneal radiotherapy for children with neuroblastoma. Methods Eight patients who received retroperitoneal radiotherapy for neuroblastoma were selected for comparison of TOMO and VMAT treatment plans. The D min , D max , D mean , D 95 , D 2 , and D 98 of planning target volume (PTV), conformity index (CI), heterogeneity index (HI), and organs at risk (OARs) parameters were compared. Delivery machine unit (MU) and image‐guide radiotherapy solution results were also compared. Results All patients received a cumulative dose of 19.5 Gy to the PTV. VMAT showed higher CI (0.93 ± 0.02), compared with TOMO (0.87 ± 0.03, P < 0.001). Notably, the average PTV HI was significantly better using TOMO (1.05 ± 0.01) than VMAT (1.08 ± 0.02, P = 0.003). Compared with VMAT, the D min , D 95 , and D 98 all exhibited increases in TOMO; D max variation was less than 1% in TOMO. The D 0.1cc for the spinal cord and D 2cc for the small intestine were better in TOMO in terms of OARs. However, TOMO had more MUs and required a longer delivery time. Interpretation Both planning techniques are capable of producing high‐ quality treatment plans. TOMO is superior for PTV coverage, but inferior for CI. TOMO requires extra treatment time; its cost is greater than the cost of VMAT.

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Is IMAT the ultimate evolution of conformal radiotherapy? Dosimetric comparison of helical tomotherapy and volumetric modulated arc therapy for oropharyngeal cancer in a planning study

Cited by 20 publications

References 16 publications

Dosimetric comparison between helical tomotherapy and volumetric modulated arc-therapy for non-anaplastic thyroid cancer treatment

Dosimetric comparison between helical tomotherapy and volumetric modulated arc-therapy for non-anaplastic thyroid cancer treatment

Dosimetric Comparisons of Volumetric Modulated Arc Therapy and Tomotherapy for Early T-Stage Nasopharyngeal Carcinoma

Dosimetric comparison of tomotherapy and volumetric‐modulated arc therapy for children with neuroblastoma

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