scholarly journals Time-Resolved Versus Integrated Transit Planar Dosimetry for Volumetric Modulated Arc Therapy

2016 ◽  
Vol 15 (6) ◽  
pp. NP79-NP87 ◽  
Author(s):  
L.C.G.G. Persoon ◽  
M. Podesta ◽  
S.M.J.J.G. Nijsten ◽  
E.G.C. Troost ◽  
F. Verhaegen
Keyword(s):  
Computed Tomography ◽  
Pleural Effusion ◽  
Tumor Regression ◽  
Control Point ◽  
Volumetric Modulated Arc Therapy ◽  
Time Resolved ◽  
Treatment Dose ◽  
Arc Therapy ◽  
Geometrical Change ◽  
Radiation Treatments

Purpose: It is desirable that dosimetric deviations during radiation treatments are detected. Integrated transit planar dosimetry is commonly used to evaluate external beam treatments such as volumetric-modulated arc therapy. This work focuses on patient geometry changes which result in differences between the planned and the delivered radiation dose. Integrated transit planar dosimetry will average out some deviations. Novel time-resolved transit planar dosimetry compares the delivered dose of volumetric-modulated arc therapy to the planned dose at various time points. Four patient cases are shown where time-resolved transit planar dosimetry detects patient geometry changes during treatment. Methods: A control point to control point comparison between the planned dose and the treatment dose of volumetric-modulated arc therapy beams is calculated using the planning computed tomography and the kV cone-beam computed tomography of the day and evaluated with a time-resolved γ function. Results were computed for 4 patients treated with volumetric-modulated arc therapy, each showing an anatomical change: pleural effusion, rectal gas pockets, and tumor regression. Results: In all cases, the geometrical change was detected by time-resolved transit planar dosimetry, whereas integrated transit planar dosimetry showed minor or no indication of the dose discrepancy. Both tumor regression cases were detected earlier in the treatment with time-resolved planar dosimetry in comparison to integrated transit planar dosimetry. The pleural effusion and the gas pocket were detected exclusively with time-resolved transit planar dosimetry. Conclusions: Clinical cases were presented in this proof-of-principle study in which integrated transit planar dosimetry did not detect dosimetrically relevant deviations to the same extent time-resolved transit planar dosimetry was able to. Time-resolved transit planar dosimetry also provides results that can be presented as a function of arc delivery angle allowing easier interpretation compared to integrated transit planar dosimetry.

scholarly journals Analysis of Dosimetric Impacts of Cone Beam Computed Tomography–Based Volumetric Modulated Arc Therapy Planning

2016 ◽  
Vol 47 (2) ◽  
pp. 160-170 ◽  
Author(s):  
Manthala Padannayil Noufal ◽  
Kallikuzhiyil Kochunny Abdullah ◽  
Puzhakal Niyas ◽  
Thekedath Sankran Sankaran ◽  
Plankudy Ragavan Sasindaran
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Volumetric Modulated Arc Therapy ◽  
Cone Beam ◽  
Therapy Planning ◽  
Arc Therapy

Time-resolved versus time-integrated portal dosimetry: the role of an object’s position with respect to the isocenter in volumetric modulated arc therapy

2016 ◽  
Vol 61 (10) ◽  
pp. 3969-3984 ◽  
Author(s):  
Lotte E J R Schyns ◽  
Lucas C G G Persoon ◽  
Mark Podesta ◽  
Wouter J C van Elmpt ◽  
Frank Verhaegen
Keyword(s):  
Volumetric Modulated Arc Therapy ◽  
Time Resolved ◽  
Portal Dosimetry ◽  
Arc Therapy

scholarly journals Access of Patients With Lung Cancer to High Technology Radiation Therapy in Brazil

2021 ◽  
pp. 726-733
Author(s):  
Lilian Dantonino Faroni ◽  
Arthur Accioly Rosa ◽  
Veronica Aran ◽  
Renan Serrano Ramos ◽  
Carlos Gil Ferreira
Keyword(s):  
Public Health ◽  
Computed Tomography ◽  
Lung Cancer ◽  
Radiation Therapy ◽  
Cone Beam Computed Tomography ◽  
Volumetric Modulated Arc Therapy ◽  
High Technology ◽  
Cone Beam ◽  
Intensity Modulated ◽  
Arc Therapy

PURPOSE Lung cancer is a global health problem, with more than 220,000 new cases and 150,000 deaths per year in the United States. Likewise, in Brazil, lung cancer is the most lethal cancer with 30,200 new cases expected in 2020. Regarding treatment types, radiation therapy (RT) represents an important approach, since 60%-70% of the patients will receive this modality of treatment during the course of their disease. However, access to RT remains challenging because of the socioeconomic inequalities in the Brazilian population, where approximately 100,000 patients/year die without access to RT. This work provides an overview on the availability of high technology RT in Brazil. METHODS A retrospective study was performed using the Brazilian Radiotherapy Census, local public and private databases, and the current literature published in 2019. RESULTS The Brazilian radiotherapy network relies on approximately 363 linear accelerators and 20 cobalt machines that remain operational. Most of these machines are installed at public health facilities. Regarding high technology, intensity-modulated RT is available in 53.7% (n = 130) and volumetric modulated arc therapy in 28.5% (n = 69) of the institutions, although only 19.8% (n = 48) of those facilities are capable of performing image-guided RT using cone beam computed tomography. Considering only the public health care system, the scenario is more restricted, with 40.1% (n = 65) of the institutions offering intensity-modulated RT, 21% (n = 34) volumetric modulated arc therapy, and 14.8% (n = 24) using cone beam computed tomography. Because of these scare resources, only 16% of Radiation Departments offer stereotactic body RT. CONCLUSION Brazil still needs to improve and provide high and safer RT technologies to patients with lung cancer across all Brazilian regions to attend the population needs and obtain better patient outcomes.

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