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ABSTRACT: Purpose: To compare the traditional Snake model and Balloon-Snake model on automatic organ contouring. Methods: For tumors in brain, chest and abdomen, two patients were enrolled for each part. Grey matter, lung and liver for each patient were contoured automatically by Snake model and Balloon-Snake model, and were also contoured manually by radiologist respectively. Characteristics and dynamic capabilities were compared between the two models. Results: The traditional Snake model will bring good contouring Result only if the primary contour is close enough to the target edge. But, if the force field area is relatively small, the automatic contouring will not bring good Result on boundary deep concave. The Balloon-Snake model can overcome those shortcomings and improve the traditional Snake model. However, the primary model of Balloon-Snake can not cross border, doesn't work well on boundary cracks reconstruction, has small force field. Conclusions: The Balloon-Snake model improved the traditional Snake model and has better dynamic capabilities. It has also more practical value on automatic organ contouring.
Medical Physics 06/2012; 39(6):3629. · 2.83 Impact Factor
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ABSTRACT: The aim of this paper is to compare the dosimetric difference between intensity-modulated arc therapy (IMAT) and conventional intensity-modulated radiation therapy (IMRT) for radiotherapy of nasopharyngeal carcinoma (NPC) using simultaneously integrated boost (SIB) protocol. Ten patients with nasopharyngeal carcinoma underwent SIB protocol were retrospectively studied. The plan target volume (PTV) of NPC contained nasopharynx gross target volume and the positive neck lymph nodes, PTV1 contained the high-risk sites of microscopic extension and the whole nasopharynx and PTV2 contained the low-risk sites. The prescription dose of PTV was 66 Gy/30 fractions, and for PTV1 60 Gy/30 fractions and for PTV2 54 Gy/30 fractions. IMAT (two 358° arcs) and IMRT (7 fields) plans were designed for each patients using SIB strategies. The monitor unit (MU), treatment time (T) and dosimetric difference between IMRT and IMAT were compared. IMAT can achieve better conformal index (CI) than IMRT (P < 0.05) for all PTVs, while no significant difference were found in homogeneity index (HI) (P > 0.05). There's no significant difference found in radiation dose of brain stem, lenses and parotids, while the maximum dose of spinal cord of IMAT was higher than IMRT (P < 0.05). The monitor unit of IMRT (1308 ± 213) was more than IMAT (606 ± 96) (P < 0.05), while the treatment time of IMRT (540 ± 160S) was more than IMAT (160 ± 10S). This study shows that IMAT using SIB strategies for NPC radiotherapy can achieve similar target coverage with better conformity with less MU and delivery time comparing to IMRT.
Technology in cancer research & treatment 05/2012; 11(5):415-20. · 2.02 Impact Factor
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G Z Gong,
Y Yin,
L G Xing,
Y J Guo,
T Liu,
J Chen,
J Lu,
C Ma,
T Sun, T Bai,
G Zhang,
R Wang
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ABSTRACT: The goal of this research was to investigate the feasibility of volumetric modulated arc therapy, RapidArc (RA), in association with the active breathing coordinator (ABC) for the treatment of hepatocellular carcinoma (HCC) with radiotherapy.
A total of 12 patients with HCC, after receiving transcatheter arterial chemoembolization (TACE) treatment, underwent three-dimensional computer tomography (3D-CT) scanning associated with ABC using end inspiration hold (EIH), end expiration hold (EEH), and free breathing (FB) techniques. The three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and RA plans (three 135° arcs) were designed on different CT images, respectively. The liver volume, gross tumor volume (GTV), and planning target volume (PTV) of the three breath status and the dosimetric differences of the different plans were compared.
There were no significant differences in the volumes of live and GTV between the three breathing techniques (p > 0.05); the PTV in FB was greater than in the EEH and EIH (p < 0.05). The overall conformality index (CI) and homogeneity index (HI) for RA (CI 0.92, HI 0.90) were better than IMRT (CI 0.90, HI 0.89) and 3D-CRT (CI 0.70, HI 0.84) for the three breathing techniques (p< 0.05). The RA and IMRT significantly reduced the mean dose, V(20), V(30), and V(40) of normal liver compared to 3D-CRT, while the V(5) and V(10) in RA were higher than in IMRT. The mean values in mean dose, V(10), V(20), V(30), and V(40) of the normal liver were reduced from 13.12 Gy, 46%, 24%, 13%, and 8% in RA(FB) to 10.23 Gy, 35%, 16%, 8%, and 5% in RA(EEH) and 9.23 Gy, 32%, 16%, 8%, and 5% in RA(EIH ), respectively. In addition, the treatment time of RA was equal to 3D-CRT, which was significantly shorter than IMRT.
RA in conjunction with ABC for the treatment of HCC with radiotherapy can achieve better dose delivery and ensure the accuracy of the target volume, which spares more organs at risk, uses fewer monitor units, and shortens treatment time.
Strahlentherapie und Onkologie 02/2012; 188(3):262-8. · 3.56 Impact Factor
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G Gong,
Y Yin,
L Xing,
Y Guo,
J Chen,
T Liu,
J Lu,
C Ma,
T Sun, T Bai,
G Zhang,
W Deng
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ABSTRACT: The aim of this paper is to study the feasibility for determining the individual internal target volume (ITV) for hepatocellular carcinoma (HCC) using 3DCT associated with active breathing coordinator (ABC), comparing the ITVs defined by 3DCT associated with ABC and 4DCT. Thirteen patients with HCC after transarterial chemoembolization (TACE) treatment underwent 4DCT simulation and 3DCT simulation associated with ABC in free breathing (FB), end inspiration hold (EIH) and end expiration hold (EEH). The 4DCT images were sorted into 10 phases according to the respiratory cycle and labeled as CT(0), CT(10)...CT(90); and CT(MIP) (the maximum intensity projection image) was reconstructed. GTV(0), GTV(10)...GTV(90), GTV(MIP) on 4DCT, and the GTV(FB), GTV(EIH), GTV(EEH) on 3DCT were contoured. GTV(0,10...90), GTV(0) and GTV(50), GTV(EIH) and GTV(EEH) were merged into ITV(1), ITV(2) and ITV(3). The individual margins from GTV(FB) to ITV(1-3) were obtained and applied to ITV(FB) (labeled as ITV(FB-1), ITV(FB-2), ITV(FB-3)), respectively. All the target volumes were normalized by ITV(1). The volume of GTVs, ITVs and the margins were compared. There was no significant difference of diaphragm mobility between 4DCT and 3DCT (P > 0.05), nor significant difference among the volume of the GTVs. The three ITVs were larger than the GTV(MIP) (P < 0.05), but there was no significant difference among three ITVs. It's similar to the differences both in the margins of three dimensions from GTV(FB) to ITV(1-3) and in the volumes among ITV(FB-1), ITV(FB-2) and ITV(FB-3) (P > 0.05). This study shows that it's safe and feasible to determine the individual ITV for HCC using 3DCT associated with ABC in comparison with 4DCT.
Technology in cancer research & treatment 12/2011; 10(6):601-6. · 2.02 Impact Factor
