Plan comparison of prostate stereotactic radiotherapy in spacer implant patients.
J Appl Clin Med Phys
; 22(9): 280-288, 2021 Sep.
Article
en En
| MEDLINE
| ID: mdl-34359100
ABSTRACT
In prostate stereotactic body radiation therapy (SBRT), hydrogel spacers are increasingly used. This study aimed to perform a dosimetry comparison of treatment plans using CyberKnife (CK), commonly used for prostate SBRT, Helical TomoTherapy (HT), and TrueBeam (TB) in patients with hydrogel spacer implantations. The data of 20 patients who received hydrogel spacer implantation for prostate SBRT were retrospectively analyzed. The prescription dose was 36.25 Gy in five fractions to 95% of the planning target volume (PTV; D95). The conformity index (CI), gradient index (GI), homogeneity index (HI), and dose-volume histogram (DVH) were analyzed for the three modalities, using the same PTV margins. The monitor unit (MU) and the beam-on-time (BOT) values were subsequently compared. The CI of TB (0.93 ± 0.02) was significantly superior to those of CK (0.82 ± 0.03, p < 0.01) and HT (0.86 ± 0.03, p < 0.01). Similarly, the GI value of TB (3.59 ± 0.12) was significantly better than those of CK (4.31 ± 0.43, p < 0.01) and HT (4.52 ± 0.24, p < 0.01). The median doses to the bladder did not differ between the CK and TB (V18.1 Gy 16.5% ± 4.5% vs. 15.8% ± 4.4%, p = 1.00), but were significantly higher for HT (V18.1 Gy 33.2% ± 7.3%, p < 0.01 vs. CK, p < 0.01 vs. TB). The median rectal dose was significantly lower for TB (V18.1 Gy 5.6% ± 4.5%) than for CK (V18.1 Gy 11.2% ± 6.7%, p < 0.01) and HT (20.2% ± 8.3%, p < 0.01). TB had the shortest BOT (2.6 min; CK 17.4 min, HT 6.9 min). TB could create treatment plans dosimetrically comparable to those of CK when using the same margins, in patients with hydrogel spacers.
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Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Radiocirugia
/
Radioterapia de Intensidad Modulada
Tipo de estudio:
Observational_studies
Límite:
Humans
/
Male
Idioma:
En
Revista:
J Appl Clin Med Phys
Asunto de la revista:
BIOFISICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Japón