Spatially Fractionated GRID Radiation Treatment of Advanced Neck Disease Associated with Head and Neck Cancer

Huhn, J.L.; Regine, William F.; Valentino, Joseph; Meigooni, Ali S.; Kudrimoti, Mahesh; Mohiuddin, Mohammed

doi:10.1177/153303460600500608

Cited by 75 publications

(88 citation statements)

References 21 publications

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“…Although some of the previous clinical and theoretical investigations have demonstrated that it is expected to see a better therapeutic response for radioresistant tumors in grid therapy, 5 , 7 there was no systematic proof of that. The results of the present study emphasize that even for radioresistant tumors, clinical responses of grid therapy may vary with the SF2 value.…”

Section: Discussionmentioning

confidence: 99%

“…The clinical responses of the patients from different publications, which were treated with grid therapy, have been used to validate the results of the model introduced in this investigation 7 , 9 , 10 , 18 , 19 , 20 . Since the correlation of the responses of the grid therapy with the radiation sensitivity of tumors that were needed from each publication, we focused on the total responses of the treatments, based on the tumor histology and treatment site.…”

Section: Methodsmentioning

confidence: 99%

“…All the clinical reports of grid therapy referred to curative or palliative advanced tumors (mostly stage III/IV) with sizes larger than 6 cm. The patients in the publications had chemotherapy, except in the clinical report by Huhn et al (7) in which 7 of 27 patients were treated with chemoradiation in grid technique for advanced SCC of head and neck (H&N) tumors. Moreover, these patients normally received full standard radiotherapy after a few days from completion of the grid therapy.…”

Section: Methodsmentioning

confidence: 99%

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Is grid therapy useful for all tumors and every grid block design?

Gholami

Nedaie

Longo

et al. 2016

J Applied Clin Med Phys

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Grid therapy is a treatment technique that has been introduced for patients with advanced bulky tumors. The purpose of this study is to investigate the effect of the radiation sensitivity of the tumors and the design of the grid blocks on the clinical response of grid therapy. The Monte Carlo simulation technique is used to determine the dose distribution through a grid block that was used for a Varian 2100C linear accelerator. From the simulated dose profiles, the therapeutic ratio (TR) and the equivalent uniform dose (EUD) for different types of tumors with respect to their radiation sensitivities were calculated. These calculations were performed using the linear quadratic (LQ) and the Hug‐Kellerer (H‐K) models. The results of these calculations have been validated by comparison with the clinical responses of 232 patients from different publications, who were treated with grid therapy. These published results for different tumor types were used to examine the correlation between tumor radiosensitivity and the clinical response of grid therapy. Moreover, the influence of grid design on their clinical responses was investigated by using Monte Carlo simulations of grid blocks with different hole diameters and different center‐to‐center spacing. The results of the theoretical models and clinical data indicated higher clinical responses for the grid therapy on the patients with more radioresistant tumors. The differences between TR values for radioresistant cells and radiosensitive cells at 20 Gy and 10 Gy doses were up to 50% and 30%, respectively. Interestingly, the differences between the TR values with LQ model and H‐K model were less than 4%. Moreover, the results from the Monte Carlo studies showed that grid blocks with a hole diameters of 1.0 cm and 1.25 cm may lead to about 19% higher TR relative to the grids with hole diameters smaller than 1.0 cm or larger than 1.25 cm (with 95% confidence interval). In summary, the results of this study indicate that grid therapy is more effective for tumors with radioresistant characteristics than radiosensitive tumors.PACS number(s): 87.55.‐x

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Is grid therapy useful for all tumors and every grid block design?

Gholami

Nedaie

Longo

et al. 2016

J Applied Clin Med Phys

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“…While the existing clinical studies 1,5 suggest improved tumour control especially for resistant tumours to conventional radiation, such as melanomas and soft tissue sarcomas, the radiobiological mechanisms of grid therapy are not fully explored. Many studies have been undertaken in order to understand the radiobiological effects of the grid treatment on tumour cells.…”

Section: 2mentioning

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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“…6 GRID has been successfully used as part of palliative and curative treatments of large head and neck tumours, showing excellent initial response rates with low toxicity. 2,7 The complex, non-uniform dose distributions delivered during GRID therapy may be of significant importance to the underlying radiobiological mechanism of response. Using more simplistic approaches to generate non-uniform dose distributions in vitro, focused on the impact of steep dose gradients, our group has shown important contributions of non-targeted radiobiological effects driven by intercellular signalling, commonly known as bystander effects.…”

Section: Introductionmentioning

confidence: 99%