Dosimetric characteristics with spatial fractionation using electron grid therapy

Meigooni, Ali S.; Parker, Stephanie; Zheng, Jicui; Kalbaugh, Kevin J.; Regine, William F.; Mohiuddin, Majid

doi:10.1016/s0958-3947(02)00086-9

Cited by 25 publications

(34 citation statements)

References 6 publications

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“…Whereas the low-dose bystander effect in a biological system is of relevance to carcinogenesis and could have serious implications for radiation risk assessment, the bystander signaling induced by a high dose has therapeutic implications. High-dose RIBEs could be the underlying mechanism involved in a novel treatment modality, such as high-dose spatially fractionated radiation GRID therapy for management of advanced cancers (33)(34)(35)(36)(37). Significant induction of LDL-enriched ceramide, secretory SMase, and TNF-a in serum from patients treated with spatially fractionated Figure 5.…”

Section: Discussionmentioning

confidence: 99%

Role of Tumor Necrosis Factor-α and TRAIL in High-Dose Radiation–Induced Bystander Signaling in Lung Adenocarcinoma

et al. 2007

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Section: Discussionmentioning

confidence: 99%

Role of Tumor Necrosis Factor-α and TRAIL in High-Dose Radiation–Induced Bystander Signaling in Lung Adenocarcinoma

et al. 2007

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“…( 1 – 3 ) The technique has shown high efficacy for bulky tumors receiving doses of 10 to 20 Gy in a single fraction. ( 2 ) The biological mechanisms of this technique are not fully understood, although several theories have been proposed. ( 2 ) For patients who undergo GRID therapy followed by conventional fractionated radiation therapy, it has been speculated that the high cell kill of the GRID fraction induces re‐oxygenation, which improves the outcome of the subsequent conventional radiation therapy.…”

Section: Introductionmentioning

confidence: 99%

“…( 2 ) The biological mechanisms of this technique are not fully understood, although several theories have been proposed. ( 2 ) For patients who undergo GRID therapy followed by conventional fractionated radiation therapy, it has been speculated that the high cell kill of the GRID fraction induces re‐oxygenation, which improves the outcome of the subsequent conventional radiation therapy. ( 4 ) Furthermore, despite the large single fraction, minimal skin radiation side effects are observed with spatially fractionated radiotherapy since only a small portion of the skin is exposed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a commercially‐available block for spatially fractionated radiation therapy

Buckey

Stathakis

Cashon³

et al. 2010

J Applied Clin Med Phys

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In this paper, we present the dosimetric characteristics of a commercially‐produced universal GRID block for spatially fractioned radiation therapy. The dosimetric properties of the GRID block were evaluated. Ionization chamber and film measurements using both Kodak EDR2 and Gafchromic EBT film were performed in a solid water phantom to determine the relative output of the GRID block as well as its spatial dosimetric characteristics. The surface dose under the block and at the openings was measured using ultra thin TLDs. After introducing the GRID block into the treatment planning system, a treatment plan was created using the GRID block and also by creating a GRID pattern using the multi‐leaf collimator. The percent depth doses measured with film showed that there is a shift of the normaldmax towards shallower depths for both energies (6 MV and 18 MV) under investigation. It was observed that the skin dose at the GRID openings was higher than the corresponding open field by a factor as high as 50% for both photon energies. The profiles showed the transmission under the block was in the order of 15–20% for 6 MV and 30% for 18 MV. The MUs calculated for a real patient using the block were about 80% less than the corresponding MUs for the same plan using the multileaf collimator to define the GRID. Based on this investigation, this brass GRID compensator is a viable alternative to other solid compensators or MLC‐based fields currently in use. Its ease of creation and use give it decided advantages. Its ability to be created once and used for multiple patients (by varying the collimation of the linear accelerator jaws) makes it attractive from a cost perspective. We believe this compensator can be put to clinical use, and will allow more centers to offer GRID therapy to their patients.PACS number: 87.53.Mr

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“…In the high-dose regions, discrepancies between the measured and calculated dose values were within 2%, in accordance to the increased precision of the radiochromic film dosimetry system at higher doses. 15 Results presented in Table 1 and Figures 3 and 5 indicate that the commissioning process for the grid block incorporation into the Eclipse TPS described in this work results in acceptable dosimetric accuracy. In addition, the incorporation of the grid block into the R&V system provides a safe way of treatment and prevents an adverse dose delivery that could be implicated by an attempt to deliver a plan with a field size larger than 25 3 25 cm at the isocentre plane.…”

Section: Resultsmentioning

confidence: 75%

“…Grid holes have a diameter of 1.4 and 2.1 cm centre-to-centre spacing when projected at an orthogonal to the beam plane 100 cm from the source. The actual grid block design was based on the previous work of Meigooni et al 15 and Stathakis et al 16 To measure the size of the holes and their spacing, we irradiated a piece of EBT3 model GAFCHROMIC TM film (Ashland, Wayne, NJ) positioned at the isocentre (Figure 2d). The beam centre was first marked on the film piece prior to insertion of the grid block using the beam cross hair.…”

Section: Grid Treatment Planning System Commissioningmentioning

confidence: 99%

Effective spatially fractionated GRID radiation treatment planning for a passive grid block

Nobah¹,

Mohiuddin²,

Dević³

et al. 2015

BJR

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Objective: To commission a grid block for spatially fractionated grid radiation therapy (SFGRT) treatments and describe its clinical implementation and verification through the record and verify (R&V) system. Methods: SFGRT was developed as a treatment modality for bulky tumours that cannot be easily controlled with conventionally fractionated radiation. Treatment is delivered in the form of open-closed areas. Currently, SFGRT is performed by either using a commercially available grid block or a multileaf collimator (MLC) of a linear accelerator. In this work, 6-MV photon beam was used to study dosimetric characteristics of the grid block. We inserted the grid block into a commercially available treatment planning system (TPS), and the feasibility of delivering such treatment plans on a linear accelerator using a R&V system was verified. Dose measurements were performed using a miniature PinPoint TM ion chamber (PTW, Freiburg, Germany) in a water phantom and radiochromic film within solid water slabs. PinPoint ion chamber was used to measure the output factors, percentage depth dose (PDD) curves and beam profiles at two depths, depth of maximum dose (z max ) and 10 cm.Film sheets were used to measure dose profiles at z max and 10-cm depth.Results: The largest observed percentage difference between output factors for the grid block technique calculated by the TPS and measured with the PinPoint ion chamber was 3.6% for the 5 3 5-cm 2 field size. Relatively significant discrepancies between measured and calculated PDD values appear only in the build-up region, which was found to amount to ,4%, while a good agreement (differences ,2%) at depths beyond z max was observed. Dose verification comparisons performed between calculated and measured dose distributions were in clinically acceptable agreements. When comparing the MLC-based with the grid block technique, the advantage of treating large tumours with a single field reduces treatment time by at least 3-5 times, having significant impact on patient throughput. Conclusion:The proposed method supports and helps to standardize the clinical implementation of the grid block in a safer and more accurate way. Advances in knowledge: This work describes the method to implement treatment planning for the grid block technique in radiotherapy departments.

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Dosimetric characteristics with spatial fractionation using electron grid therapy

Cited by 25 publications

References 6 publications

Role of Tumor Necrosis Factor-α and TRAIL in High-Dose Radiation–Induced Bystander Signaling in Lung Adenocarcinoma

Role of Tumor Necrosis Factor-α and TRAIL in High-Dose Radiation–Induced Bystander Signaling in Lung Adenocarcinoma

Evaluation of a commercially‐available block for spatially fractionated radiation therapy

Effective spatially fractionated GRID radiation treatment planning for a passive grid block

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