EPID in Vivo Dosimetry in RapidArc Technique

Overview

Journal Rep Pract Oncol Radiother

Specialty Oncology

Date 2013 Dec 31

PMID 24376916

Citations 12

Authors

Krzysztof Slosarek

Marta Szlag

Barbara Bekman

Aleksandra Grzadziel

Affiliations

Soon will be listed here.

Abstract

Aim: The aim of the study was to estimate the dose at the reference point applying an aSi-EPID device in the course of patient treatment.

Materials And Methods: The method assumes direct proportionality between EPID signal and dose delivered to the patient reference point during the treatment session. The procedure consists of treatment plan calculation for the actual patient in the arc technique. The plan was realized with an elliptic water-equivalent phantom. An ionization chamber inside the phantom measured the dose delivered to the reference point. Simultaneously, the EPID matrix measured the CU distribution. EPID signal was also registered during patient irradiation with the same treatment plan. The formula for in vivo dose calculation was based on the CU(g) function, EPID signal registered during therapy and the relation between the dose and EPID signal level measured for the phantom. In vivo dose was compared with dose planned with the treatment planning system. Irradiation was performed with a Clinac accelerator by Varian Medical Systems in the RapidArc technique. The Clinac was equipped with an EPID matrix (electronic portal image device) of aSi-1000. Treatment plans were calculated with the Eclipse/Helios system. The phantom was a Scanditronix/Wellhöfer Slab phantom, and the ionization chamber was a 0.6 ccm PTW chamber.

Results: In vivo dose calculations were performed for five patients. Planned dose at the reference point was 2 Gy for each treatment plan. Mean in vivo dose was in the range of 1.96-2.09.

Conclusions: Our method was shown to be appropriate for in vivo dose evaluation in the RapidArc technique.

Citing Articles

Portal dosimetry in radiotherapy repeatability evaluation.

Slosarek K, Plaza D, Nas A, Reudelsdorf M, Wendykier J, Bekman B J Appl Clin Med Phys. 2020; 22(1):156-164.

PMID: 33314643 PMC: 7856497. DOI: 10.1002/acm2.13123.

Two-dimensional solid-state array detectors: A technique for in vivo dose verification in a variable effective area.

Utitsarn K, Biasi G, Stansook N, Alrowaili Z, Petasecca M, Carolan M J Appl Clin Med Phys. 2019; 20(11):88-94.

PMID: 31609090 PMC: 6839376. DOI: 10.1002/acm2.12744.

EPID-based daily verification of reproducibility of patients' irradiation with IMRT plans.

Kruszyna-Mochalska M Rep Pract Oncol Radiother. 2018; 23(5):309-314.

PMID: 30108458 PMC: 6088814. DOI: 10.1016/j.rpor.2018.05.003.

Diode-based transmission detector for IMRT delivery monitoring: a validation study.

Li T, Wu Q, Matzen T, Yin F, ODaniel J J Appl Clin Med Phys. 2016; 17(5):235-244.

PMID: 27685115 PMC: 5874094. DOI: 10.1120/jacmp.v17i5.6204.

Clinical examples of 3D dose distribution reconstruction, based on the actual MLC leaves movement, for dynamic treatment techniques.

Osewski W, Dolla L, Radwan M, Szlag M, Rutkowski R, Smolinska B Rep Pract Oncol Radiother. 2014; 19(6):420-7.

PMID: 25337416 PMC: 4201771. DOI: 10.1016/j.rpor.2014.04.013.

References

Fogliata A, Clivio A, Nicolini G, Vanetti E, Cozzi L . Intensity modulation with photons for benign intracranial tumours: a planning comparison of volumetric single arc, helical arc and fixed gantry techniques. Radiother Oncol. 2008; 89(3):254-62. DOI: 10.1016/j.radonc.2008.07.021. View

Otto K . Volumetric modulated arc therapy: IMRT in a single gantry arc. Med Phys. 2008; 35(1):310-7. DOI: 10.1118/1.2818738. View

Lagerwaard F, Meijer O, van der Hoorn E, Verbakel W, Slotman B, Senan S . Volumetric modulated arc radiotherapy for vestibular schwannomas. Int J Radiat Oncol Biol Phys. 2009; 74(2):610-5. DOI: 10.1016/j.ijrobp.2008.12.076. View

Verbakel W, Cuijpers J, Hoffmans D, Bieker M, Slotman B, Senan S . Volumetric intensity-modulated arc therapy vs. conventional IMRT in head-and-neck cancer: a comparative planning and dosimetric study. Int J Radiat Oncol Biol Phys. 2009; 74(1):252-9. DOI: 10.1016/j.ijrobp.2008.12.033. View

Nicolini G, Vanetti E, Clivio A, Fogliata A, Korreman S, Bocanek J . The GLAaS algorithm for portal dosimetry and quality assurance of RapidArc, an intensity modulated rotational therapy. Radiat Oncol. 2008; 3:24. PMC: 2553075. DOI: 10.1186/1748-717X-3-24. View

Van Esch A, Depuydt T, Huyskens D . The use of an aSi-based EPID for routine absolute dosimetric pre-treatment verification of dynamic IMRT fields. Radiother Oncol. 2004; 71(2):223-34. DOI: 10.1016/j.radonc.2004.02.018. View

McCurdy B, Luchka K, Pistorius S . Dosimetric investigation and portal dose image prediction using an amorphous silicon electronic portal imaging device. Med Phys. 2001; 28(6):911-24. DOI: 10.1118/1.1374244. View

Shaffer R, Morris W, Moiseenko V, Welsh M, Crumley C, Nakano S . Volumetric modulated Arc therapy and conventional intensity-modulated radiotherapy for simultaneous maximal intraprostatic boost: a planning comparison study. Clin Oncol (R Coll Radiol). 2009; 21(5):401-7. DOI: 10.1016/j.clon.2009.01.014. View

Steciw S, Warkentin B, Rathee S, Fallone B . Three-dimensional IMRT verification with a flat-panel EPID. Med Phys. 2005; 32(2):600-12. DOI: 10.1118/1.1843471. View

10.

Piermattei A, Fidanzio A, Azario L, Grimaldi L, DOnofrio G, Cilla S . Application of a practical method for the isocenter point in vivo dosimetry by a transit signal. Phys Med Biol. 2007; 52(16):5101-17. DOI: 10.1088/0031-9155/52/16/026. View

11.

Greer P . Correction of pixel sensitivity variation and off-axis response for amorphous silicon EPID dosimetry. Med Phys. 2006; 32(12):3558-68. DOI: 10.1118/1.2128498. View

12.

El-Mohri Y, Antonuk L, Yorkston J, Jee K, Maolinbay M, Lam K . Relative dosimetry using active matrix flat-panel imager (AMFPI) technology. Med Phys. 1999; 26(8):1530-41. DOI: 10.1118/1.598649. View

13.

Cozzi L, Fogliata A, Nicolini G . Pre-treatment verification of intensity modulated photon beams with films and electronic portal imaging--two years of clinical experience. Z Med Phys. 2005; 14(4):239-50. DOI: 10.1078/0939-3889-00226. View

14.

. Intensity-modulated radiotherapy: current status and issues of interest. Int J Radiat Oncol Biol Phys. 2001; 51(4):880-914. DOI: 10.1016/s0360-3016(01)01749-7. View

15.

Cozzi L, Dinshaw K, Shrivastava S, Mahantshetty U, Engineer R, Deshpande D . A treatment planning study comparing volumetric arc modulation with RapidArc and fixed field IMRT for cervix uteri radiotherapy. Radiother Oncol. 2008; 89(2):180-91. DOI: 10.1016/j.radonc.2008.06.013. View

16.

Winkler P, Hefner A, Georg D . Dose-response characteristics of an amorphous silicon EPID. Med Phys. 2005; 32(10):3095-105. DOI: 10.1118/1.2040711. View

17.

Greer P, Popescu C . Dosimetric properties of an amorphous silicon electronic portal imaging device for verification of dynamic intensity modulated radiation therapy. Med Phys. 2003; 30(7):1618-27. DOI: 10.1118/1.1582469. View

18.

Vieira S, Dirkx M, Heijmen B, de Boer H . SIFT: a method to verify the IMRT fluence delivered during patient treatment using an electronic portal imaging device. Int J Radiat Oncol Biol Phys. 2004; 60(3):981-93. DOI: 10.1016/j.ijrobp.2004.06.025. View