Single isocenter stereotactic irradiation for multiple brain metastases: current situation and prospects

Uto, Megumi; Torizuka, Daichi; Mizowaki, Takashi

doi:10.1007/s11604-022-01333-7

Cited by 4 publications

(3 citation statements)

References 52 publications

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“…With the development of technology, advances in radiotherapy devices and application methods have brought radiotherapy to the forefront among cancer treatment modalities. 2 , 3 Despite such advances, factors such as radioresistant tumors (eg, hypoxia) or low-tolerance doses of organs at risk around the target area can limit the effectiveness of radiotherapy. 4 …”

Section: Introductionmentioning

confidence: 99%

The Effect of Dose Enhancement in Tumor With Silver Nanoparticles on Surrounding Healthy Tissues: A Monte Carlo Study

ÇAĞLAR,

EŞİTMEZ,

CEBE

2024

Technol Cancer Res Treat

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Objectives: Cancer-related death rates account for approximately one-third of all deaths, and this rate is increasing remarkably every year. In this study, we examined the dose enhancement factor (DEF) in the tumor and surrounding tissues by adding different concentrations of silver nanoparticles (AgNPs) to the brain tumor using the Monte Carlo (MC) technique. Methods: This study used MCNP6.2 simulation software. A Planning Target Volume (PTV) of 1 × 1 × 1 cm3 was placed in the center of a cubic cranial model with dimensions of 5 × 5 × 5 cm3. Five different simulations were initially generated using the simple method. These simulations included pure PTV and PTV consisting of 4 different silver concentrations (5, 10, 20, and 30 mg/g). Additionally, a model was created using the nanolattice method, considering the size, position, and distribution of the AgNPs. Irradiation was performed using a source with a 6 MV linac photon spectrum. Measurements were performed using the *f8 tally, and DEF values were calculated. Results: In the simulation study using the simple method, the DEF value of PTV increased linearly with concentration, whereas the DEF values were lower than the simulation results with the nanolattice model (1.9 vs 1.4 for 30 mg/g NP concentration). Performing the simple method, we observed no remarkable dose increase in lateral OARs surrounding PTV. While a remarkable dose decrease was observed in distal OARs, a dose increase in the proximal OAR was observed, which was consistent with that of PTV. However, according to the results obtained by performing the nanolattice method, the dose increase was observed in both the proximal OAR and the distal OAR and was similar to that of PTV. Conclusion: While enhancing the dose in the tumor by adding NPs into the tumor, it is essential to consider whether it also increases the OAR dose. In addition, simulation studies on NPs showed that the dose increase varied significantly with particle size, position, and distribution. Hence, these factors should be considered carefully.

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Section: Introductionmentioning

confidence: 99%

The Effect of Dose Enhancement in Tumor With Silver Nanoparticles on Surrounding Healthy Tissues: A Monte Carlo Study

ÇAĞLAR,

EŞİTMEZ,

CEBE

2024

Technol Cancer Res Treat

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“…However, rotational setup errors result in reduced target coverage with increasing isocenter‐to‐target distance 4,5 . In recent years, the simultaneous irradiation of multiple brain metastases using a single isocenter has become more common 6,7 . Failure to correct rotational setup errors can result in PTV underdosage 8 .…”

Section: Introductionmentioning

confidence: 99%

“… 4 , 5 In recent years, the simultaneous irradiation of multiple brain metastases using a single isocenter has become more common. 6 , 7 Failure to correct rotational setup errors can result in PTV underdosage. 8 This can be mitigated by adding an increased margin when creating the planning target volume (PTV), but is then associated with an increased dose to healthy brain tissue and could potentially pose a higher risk of adverse radiation effects.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a head rest prototype for rotational corrections in three degrees of freedom

Schindhelm,

Razinskas,

Ringholz

et al. 2023

J Applied Clin Med Phys

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Cranial stereotactic irradiations require accurate reproduction of the planning CT patient position at the time of treatment, including removal of rotational offsets. A device prototype was evaluated for potential clinical use to correct rotational positional offsets in image‐guided radiotherapy workflow. Analysis was carried out with a prototype device “RPS head” by gKteso GmbH, rotatable up to 4° in three dimensions by hand wheels. A software tool accounts for the nonrectangular rotation axes and also indicates translational motions to be performed with the standard couch to correct the initial offset and translational shifts introduced by the rotational motion. The accuracy of angular corrections and positioning of an Alderson RANDO head phantom using the prototype device was evaluated for nine treatment plans for cranial targets. Corrections were obtained from cone beam computed tomography (CBCT) imaging. The phantom position was adjusted and the final position was then verified by another CBCT. The long‐term stability of the prototype device was evaluated. Attenuation by the device along its three main axes was assessed. A planning study was performed to evaluate if regions of high‐density material can be avoided during plan generation. The device enabled the accurate correction of rotational offsets in a clinical setup with a mean residual angular difference of (0.0 ± 0.1)° and a maximum deviation of 0.2°. Translational offsets were less than 1 mm. The device was stable over a period of 20 min, not changing the head support plate position by more than (0.7 ± 0.6) mm. The device contains high‐density material in the adjustment mechanism and slightly higher density in the support structures. These can be avoided during planning generation maintaining comparable plan quality. The head positioning device can be used to correct rotational offsets in a clinical setting.

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The current state and future perspectives of radiotherapy for cervical cancer

Yamada,

Kawamura,

Oie

et al. 2024

J of Obstet and Gynaecol

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Radiotherapy is an effective treatment method for cervical cancer and is typically administered as external beam radiotherapy followed by intracavitary brachytherapy. In Japan, center shielding is used in external beam radiotherapy to shorten treatment time and reduce the doses delivered to the rectum or bladder. However, it has several challenges, such as uncertainties in calculating the cumulative dose. Recently, external beam radiotherapy has been increasingly performed with intensity‐modulated radiotherapy, which reduces doses to the rectum or bladder without center shielding. In highly conformal radiotherapy, uncertainties in treatment delivery, such as inter‐fractional anatomical structure movements, affect treatment outcomes; therefore, image‐guided radiotherapy is essential for appropriate and safe performance. Regarding intracavitary brachytherapy, the use of magnetic resonance imaging‐based image‐guided adaptive brachytherapy is becoming increasingly widespread because it allows dose escalation to the tumor and accurately evaluates the dose delivered to the surrounding normal organs. According to current evidence, a minimal dose of D90% of the high‐risk clinical target volume is significantly relevant to local control. Further improvements in target coverage have been achieved with combined interstitial and intracavity brachytherapy for massive tumors with extensive parametrical involvement. Introducing artificial intelligence will enable faster and more accurate generation of brachytherapy plans. Charged‐particle therapies have biological and dosimetric advantages, and current evidence has proven their effectiveness and safety in cervical cancer treatment. Recently, radiotherapy‐related technologies have advanced dramatically. This review provides an overview of technological innovations and future perspectives in radiotherapy for cervical cancer.

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Single isocenter stereotactic irradiation for multiple brain metastases: current situation and prospects

Cited by 4 publications

References 52 publications

The Effect of Dose Enhancement in Tumor With Silver Nanoparticles on Surrounding Healthy Tissues: A Monte Carlo Study

The Effect of Dose Enhancement in Tumor With Silver Nanoparticles on Surrounding Healthy Tissues: A Monte Carlo Study

Evaluation of a head rest prototype for rotational corrections in three degrees of freedom

The current state and future perspectives of radiotherapy for cervical cancer

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