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A study on rectal dose measurement in phantom and in vivo using Gafchromic EBT3 film in IMRT and CyberKnife treatments of carcinoma of prostate.

Ganapathy K, Kurup PG, Murali V, Muthukumaran M, Subramanian SB, Velmurugan J - J Med Phys (2013)

Bottom Line: The measured doses using EBT3 films were compared with the TPS-calculated dose along the anterior rectal wall at multiple points.Gafchromic EBT3 film is a suitable detector for in vivo rectal dose measurements as it offers the possibility of analyzing the dose at multiple points.In addition, the method of extending this in vivo rectal dose measurement technique as a tool for patient-specific quality assurance check is also analyzed.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Apollo Specialty Hospital, Chennai, Tamil Nadu, India.

ABSTRACT
The objective of this study is to check the feasibility of in vivo rectal dose measurement in intensity-modulated radiotherapy (IMRT) and CyberKnife treatments for carcinoma prostate. An in-house pelvis phantom made with bee's wax was used in this study. Two cylindrical bone equivalent materials were used to simulate the femur. Target and other critical structures associated with carcinoma prostate were delineated on the treatment planning images by the radiation oncologist. IMRT treatment plan was generated in Oncentra Master Plan treatment planning system and CyberKnife treatment plan was generated in Multiplan treatment planning system. Dose measurements were carried out in phantom and in patient using Gafchromic EBT3 films. RIT software was used to analyze the dose measured by EBT3 films. The measured doses using EBT3 films were compared with the TPS-calculated dose along the anterior rectal wall at multiple points. From the in-phantom measurements, it is observed that the difference between calculated and measured dose was mostly within 5%, except for a few measurement points. The difference between calculated and measured dose in the in-patient measurements was higher than 5% in regions which were away from the target. Gafchromic EBT3 film is a suitable detector for in vivo rectal dose measurements as it offers the possibility of analyzing the dose at multiple points. In addition, the method of extending this in vivo rectal dose measurement technique as a tool for patient-specific quality assurance check is also analyzed.

No MeSH data available.


Related in: MedlinePlus

Registration of CBCT and planning CT images of the phantom prior to treatment execution
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Figure 3: Registration of CBCT and planning CT images of the phantom prior to treatment execution

Mentions: A seven-field IMRT treatment plan using 6 MV X-rays was generated for the phantom images with hypothetical structures [Figure 2]. The dose prescribed to the target was 2 Gy per fraction. Collapsed cone convolution algorithm was used for dose calculation. The treatment plan was then evaluated using the radiation therapy oncology group (RTOG) constraints and transferred for treatment delivery. IMRT treatment was delivered from the SIEMENS ARTISTE (Ms. Siemens, Erlangen, Germany) linear accelerator. CBCT images were obtained and registered with the planning CT images to verify the accurate positioning of the isocenter in the phantom. Plastic rod and the bone inserts were clearly visible in both the planning CT images and the CBCT images. Treatment position of the phantom was verified three dimensionally by alignment of planning CT and CBCT images using the plastic rod and bone inserts as markers [Figure 3].


A study on rectal dose measurement in phantom and in vivo using Gafchromic EBT3 film in IMRT and CyberKnife treatments of carcinoma of prostate.

Ganapathy K, Kurup PG, Murali V, Muthukumaran M, Subramanian SB, Velmurugan J - J Med Phys (2013)

Registration of CBCT and planning CT images of the phantom prior to treatment execution
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3775037&req=5

Figure 3: Registration of CBCT and planning CT images of the phantom prior to treatment execution
Mentions: A seven-field IMRT treatment plan using 6 MV X-rays was generated for the phantom images with hypothetical structures [Figure 2]. The dose prescribed to the target was 2 Gy per fraction. Collapsed cone convolution algorithm was used for dose calculation. The treatment plan was then evaluated using the radiation therapy oncology group (RTOG) constraints and transferred for treatment delivery. IMRT treatment was delivered from the SIEMENS ARTISTE (Ms. Siemens, Erlangen, Germany) linear accelerator. CBCT images were obtained and registered with the planning CT images to verify the accurate positioning of the isocenter in the phantom. Plastic rod and the bone inserts were clearly visible in both the planning CT images and the CBCT images. Treatment position of the phantom was verified three dimensionally by alignment of planning CT and CBCT images using the plastic rod and bone inserts as markers [Figure 3].

Bottom Line: The measured doses using EBT3 films were compared with the TPS-calculated dose along the anterior rectal wall at multiple points.Gafchromic EBT3 film is a suitable detector for in vivo rectal dose measurements as it offers the possibility of analyzing the dose at multiple points.In addition, the method of extending this in vivo rectal dose measurement technique as a tool for patient-specific quality assurance check is also analyzed.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Apollo Specialty Hospital, Chennai, Tamil Nadu, India.

ABSTRACT
The objective of this study is to check the feasibility of in vivo rectal dose measurement in intensity-modulated radiotherapy (IMRT) and CyberKnife treatments for carcinoma prostate. An in-house pelvis phantom made with bee's wax was used in this study. Two cylindrical bone equivalent materials were used to simulate the femur. Target and other critical structures associated with carcinoma prostate were delineated on the treatment planning images by the radiation oncologist. IMRT treatment plan was generated in Oncentra Master Plan treatment planning system and CyberKnife treatment plan was generated in Multiplan treatment planning system. Dose measurements were carried out in phantom and in patient using Gafchromic EBT3 films. RIT software was used to analyze the dose measured by EBT3 films. The measured doses using EBT3 films were compared with the TPS-calculated dose along the anterior rectal wall at multiple points. From the in-phantom measurements, it is observed that the difference between calculated and measured dose was mostly within 5%, except for a few measurement points. The difference between calculated and measured dose in the in-patient measurements was higher than 5% in regions which were away from the target. Gafchromic EBT3 film is a suitable detector for in vivo rectal dose measurements as it offers the possibility of analyzing the dose at multiple points. In addition, the method of extending this in vivo rectal dose measurement technique as a tool for patient-specific quality assurance check is also analyzed.

No MeSH data available.


Related in: MedlinePlus