Study of a treatment planning system efficiency to estimate the absorbed dose by pacemakers in external radiotherapy

Abstract Background: To evaluate the reduction, the absorbed dose delivered to the neurovascular bundle (NB) in patients with localized prostate cancer treated with only HDR brachytherapy and neurovascular bundle protection with Hyaluronic acid (HA) on the side of the prostate to increase the distance from NB to the radioactive sources.Material and Methods: This is the first published report in the medical literature that study a new approach to decrease neurovascular bundle toxicity and improve quality of life for patients with prostate cancer treated with radical brachytherapy as monotherapy. Transperineal HA injection on the side of the prostate into the lateral aspect of the prostate fat was used to consistently displace several autonomic fibres and vessels the lateral wall of the prostate away from radiation sources.Results: When a protection in the form of a HA layer is placed, the reduction effect at the maximum dose is between 46% and 54% (calculated values), which means the method for protection is highly recommended. The values of the absorbed dose calculated in this project have been compared with the ones given by the treatment planning system. These calculated values are similar than the ones given by the treatment planning system (56±2).Conclusions: This newly created space decreases absorbed dose in the neurovascular bundle, calculated with the TPS and measuremed by microMOSFET due to the thickness of HA.

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Absorbed dose under the lung shields in total body irradiation calculated by the CT-based three-dimesnional treatment planning system

Clinical Physiology ◽

10.1046/j.1365-2281.1998.00065.x ◽

1998 ◽

Vol 18 (3) ◽

pp. 293-293

Author(s):

Pyykkönen ◽

Tenhunen

Keyword(s):

Treatment Planning ◽

Total Body Irradiation ◽

Absorbed Dose ◽

Planning System ◽

Treatment Planning System ◽

Total Body

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Comparison of Absorbed Dose to Medium and Absorbed Dose to Water for Spine IMRT Plans Using a Commercial Monte Carlo Treatment Planning System

International Journal of Medical Physics Clinical Engineering and Radiation Oncology ◽

10.4236/ijmpcero.2014.31010 ◽

2014 ◽

Vol 03 (01) ◽

pp. 60-66 ◽

Cited By ~ 2

Author(s):

Muhammad Nauman Usmani ◽

Norihisa Masai ◽

Ryoong-Jin Oh ◽

Hiroya Shiomi ◽

Daisaku Tatsumi ◽

...

Keyword(s):

Monte Carlo ◽

Treatment Planning ◽

Absorbed Dose ◽

Planning System ◽

Treatment Planning System ◽

Absorbed Dose To Water

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Measurement with electret ion chambers of absorbed dose outside the treated volume, during external-photon radiation therapy

Nuclear Technology and Radiation Protection ◽

10.2298/ntrp201113015c ◽

2021 ◽

pp. 15-15

Author(s):

Alexandros Clouvas ◽

Anna Makridou ◽

Michalis Chatzimarkou

Keyword(s):

Radiation Therapy ◽

Treatment Planning ◽

Absorbed Dose ◽

Planning System ◽

Photon Radiation ◽

Treatment Planning System ◽

Low Doses ◽

Prescription Dose ◽

Ion Chambers ◽

Leakage Radiation

The capabilities of electret ion chambers to measure non-target absorbed dose for distances greater than 20 cm from the irradiated volume during radiotherapy treatment was investigated for the first time. During radiotherapy, nontarget doses can be classified as one of three approximate dose levels: high doses, intermediate doses and low doses. Low doses (<5 % of the prescription dose) are not generally considered during treatment planning, due to the fact that is difficult to measure, characterize, or model them in the planning system. In this work were performed measurements with electret ion chambers of absorbed dose outside the treated volume (<5 % of the prescription dose), during external photon radiation therapy in an Elekta Infinity Linear Accelerator of ?Theagenio? Cancer Hospital of Thessaloniki, Greece. The absorbed dose values for distances greater than 20 cm from the irradiated volume varied from 0.3 to 17 mGy which corresponds to 0.01% up to 0.6% of the prescription dose (2660 mGy). Near the irradiation volume the absorbed dose values were greater than the upper detection limit of the electret ion chambers (threshold 40 mGy). The results are compared with the calculated ones by the Monaco Treatment Planning System (Elekta Monaco 5.11.03). In the non-target radiation region where Monaco Treatment Planning System calculates rather precisely (within uncertainties of less than 10%) the absorbed dose, measured and calculated doses are the same within experimental uncertainties. On the contrary, when leakage radiation becomes the dominant source of out-of-field dose the differences are up to 31%.

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Experimental validation of Monte Carlo based treatment planning system in bone density equivalent media

Radiology and Oncology ◽

10.2478/raon-2020-0051 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Djeni Smilovic Radojcic ◽

Bozidar Casar ◽

David Rajlic ◽

Manda Svabic Kolacio ◽

Ignasi Mendez ◽

...

Keyword(s):

Monte Carlo ◽

Bone Density ◽

Treatment Planning ◽

Absorbed Dose ◽

Dose Calculation ◽

Planning System ◽

Treatment Planning System ◽

Absorbed Doses ◽

Calculation Algorithms ◽

Dose Calculation Algorithms

AbstractIntroductionAdvanced, Monte Carlo (MC) based dose calculation algorithms, determine absorbed dose as dose to medium-in-medium (Dm,m) or dose to water-in-medium (Dw,m). Some earlier studies identified the differences in the absorbed doses related to the calculation mode, especially in the bone density equivalent (BDE) media. Since the calculation algorithms built in the treatment planning systems (TPS) should be dosimetrically verified before their use, we analyzed dose differences between two calculation modes for the Elekta Monaco TPS. We compared them with experimentally determined values, aiming to define a supplement to the existing TPS verification methodology.Materials and methodsIn our study, we used a 6 MV photon beam from a linear accelerator. To evaluate the accuracy of the TPS calculation approaches, measurements with a Farmer type chamber in a semi-anthropomorphic phantom were compared to those obtained by two calculation options. The comparison was made for three parts of the phantom having different densities, with a focus on the BDE part.ResultsMeasured and calculated doses were in agreement for water and lung equivalent density materials, regardless of the calculation mode. However, in the BDE part of the phantom, mean dose differences between the calculation options ranged from 5.7 to 8.3%, depending on the method used. In the BDE part of the phantom, neither of the two calculation options were consistent with experimentally determined absorbed doses.ConclusionsBased on our findings, we proposed a supplement to the current methodology for the verification of commercial MC based TPS by performing additional measurements in BDE material.

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