Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system

Court, Laurence Edward; Tishler, Roy B.; Allen, Aaron M.; Xiang, H; Makrigiorgos, Mike; Chin, Lee M.

doi:10.1120/jacmp.v9i1.2792

Cited by 62 publications

(49 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Skin dose measurements during radiotherapy would be a useful tool for treatment monitoring, skin reaction estimation, 1 and treatment plan design and modification. [2][3][4][5][6][7] However, superficial dose is generally deposited in the build-up region, being sensitive to many factors including beam energy, beam type, beam filter, 8,9 incident angle, [10][11][12] distance, 9, 13 complex patient surface profiles, 7,14 internal heterogeneities, 15 patient movement, and deformation. These factors, especially irregular surface profiles, internal heterogeneities, movement and deformation of the treatment region, decrease the accuracy of superficial dose prediction and may result in underdosing or overdosing in specified treatment plans.…”

Section: Introductionmentioning

confidence: 99%

Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x‐ray beam

et al. 2013

View full text Add to dashboard Cite

Purpose:Čerenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for theČerenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of opticalČerenkov emission as a surrogate for the absorbed superficial dose for MV x-ray beams. Methods: In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x-ray beams.Čerenkov emission intensity and radiation dose were directly simulated in voxelized flat and cylindrical phantoms. The sampling region of superficial dosimetry based oň Cerenkov radiation was simulated in layered skin models. Angular distributions of optical emission from the surfaces were investigated. Tissue mimicking phantoms with flat and curved surfaces were imaged with a time domain gating system. The beam field sizes (50 × 50-200 × 200 mm 2 ), incident angles (0• -70 • ) and imaging regions were all varied. Results: The entrance or exit region of the tissue has nearly homogeneous energy spectra across the beam, such that theirČerenkov emission is proportional to dose. Directly simulated local intensity ofČerenkov and radiation dose in voxelized flat and cylindrical phantoms further validate that this signal is proportional to radiation dose with absolute average discrepancy within 2%, and the largest within 5% typically at the beam edges. The effective sampling depth could be tuned from near 0 up to 6 mm by spectral filtering. The angular profiles near the theoretical Lambertian emission distribution for a perfect diffusive medium, suggesting that angular correction of Cerenkov images may not be required even for curved surface. The acquisition speed and signal to noise ratio of the time domain gating system were investigated for different acquisition procedures, and the results show there is good potential for real-time superficial dose monitoring. Dose imaging under normal ambient room lighting was validated, using gated detection and a breast phantom. Conclusions

show abstract

Section: Introductionmentioning

confidence: 99%

Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x‐ray beam

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Based on the experience with pacemaker function and ionizing radiation, it is reasonable to limit dose to the IT device to a total absorbed dose of 2 Gy. Some caution should be used when estimating the absorbed dose to the IT device using treatment planning systems when the device is in the buildup region, as dose errors can be as large as 25% [6,7]. Dose to the device should be verified with thermoluminescent dosimetry.…”

Section: Discussionmentioning

confidence: 99%

Intact Functioning Of Intrathecal Pain Pump Receiving Radiation Therapy

Lauro¹,

Miften²,

Albano³

et al. 2012

J Clin Case Rep

View full text Add to dashboard Cite

Programmable Intrathecal (IT) drug delivery systems are being increasingly used with radiation therapy for cancer treatment and palliation. Ionizing radiation is assumed to cause dysfunction of the programmable IT device. However, the dose limit and safety of the IT drug delivery device used concurrently with radiotherapy have not been extensively documented. Here we report a patient who underwent the implantation of an IT pump during radiotherapy. This device was subsequently directly exposed to radiation. Estimated cumulative doses to the pump were in the range of 1.28 to 9.98 Gy. The IT pump exposed to this high-dose radiation did not pose any risk to the patient or the environment. The device was queried during and after the completion of treatment and found to be functioning without fault. This is the first case description about the successful function of an IT drug delivery device directly exposed to ionizing radiation.

show abstract

“…This is owing to the considerable uncertainty in dosimetry on the surface due to the high dose gradient as well as the low accuracy in the surface region of the calculations by commercial TPS. 14,15 Therefore, even with the lens applicator, the deviation between the measured and the calculated doses was not eliminated completely since the MOSFET dosemeters were located inside the lens applicator at depths of 1.9 mm for the micro MOSFET dosemeter and 1.4 mm for the standard MOSFET dosemeter. While not eliminating deviation entirely, the lens applicator was able to reduce the deviation for in vivo dosimetry of the eye lens.…”

Section: Discussionmentioning

confidence: 99%

“…13 In this region, dose calculation with commercial TPSs have been shown to be less accurate than in deeper parts of the body. 14,15 Even for advanced algorithms such as the anisotropic analytic algorithm (AAA v. 10; Varian® Medical Systems, Palo Alto, CA), dose calculation up to a depth of 6 mm has been shown to be inaccurate.…”

mentioning

confidence: 99%

Development of an applicator for eye lens dosimetry during radiotherapy

Park¹,

Lee²,

Kim³

et al. 2014

BJR

View full text Add to dashboard Cite

Objective: To develop an applicator for in vivo measurements of lens dose during radiotherapy. Methods: A contact lens-shaped applicator made of acrylic was developed for in vivo measurements of lens dose. This lens applicator allows the insertion of commercially available metal oxide semiconductor field effect transistors (MOSFETs) dosemeters. CT images of an anthropomorphic phantom with and without the applicator were acquired. Ten volumetric modulated arc therapy plans each for the brain and the head and neck cancer were generated and delivered to an anthropomorphic phantom. The differences between the measured and the calculated doses at the lens applicator, as well as the differences between the measured and the calculated doses at the surface of the eyelid were acquired.

show abstract

Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system

Cited by 62 publications

References 13 publications

Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x‐ray beam

Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x‐ray beam

Intact Functioning Of Intrathecal Pain Pump Receiving Radiation Therapy

Development of an applicator for eye lens dosimetry during radiotherapy

Contact Info

Product

Resources

About