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Received April 30, 2024, accepted July 24 2024, date of publication October 28 2024.

Original Research Article 

Dose Verification for LINAC-Based Stereotactic Radiosurgery 
Planned at Different Prescription Isodose Levels Using Delta4 
Phantom+

Emmanuel Fiagbedzi*, Francis Hasford and Samuel Nii Tagoe

Department of Medical Physics, University of Ghana, Ghana.

* Corresponding Author Email: emmanuel2g4@gmail.com 

ABSTRACT

Background: Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) plans and their treatment are complex 
techniques that require a comprehensive quality assurance program before they are clinically implemented. To cope with this 
intricacy, clinics must comprehensively validate treatment plans to deliver precise doses and assure patients. The study aimed 
to verify the treatment planning dose to the dose delivered at the LINAC during the SRS treatment planned at different prescrip-
tion isodoses with the new wireless Delta4 Phantom+.

Materials and Methods: Clinically accepted volumetric modulated arc therapy (VMAT) SRS plans made with the Stereotactic 
End-to-End Verification (STEEV) anthropomorphic phantom were created with six different prescription isodose level using 
6 MV flattening filter free (FFF) beam. All these VMAT SRS plans were replicated on the Delta4 Phantom+ and delivered with 
Varian Truebeam LINAC. The planned and delivered dose showed excellent correlation, and this was evaluated using distance 
to agreement (2 mm), dose deviation (2%), and gamma-index passing rate.

Results: The results showed that the calculated treatment planning system (TPS) dose and the measurement with the Delta4 
Phantom+were in excellent accord. The minimum gamma pass rate was 99.6% and the maximum 100%. The gamma passing 
rate above 95% for all plans and dose goals were achieved. 

Conclusion: The verification with the Delta4 Phantom+ measurement depicted an excellent correlation with the dose of the 
SRS treatment plans for the different prescription isodose levels. The wireless Delta4 Phantom+ device is precise and consis-
tent. It is a quickly set-up device, suitable for SRS treatment verification and allows for real-time measurement. However, we do 
recommend a stricter passing rate for VMAT SRS Plans. 

Keywords—Stereotactic radiosurgery, prescription isodose, treatment plans, Delta4 Phantom+, Gamma-index.

Copyright © 2024. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY): Creative Commons - 
Attribution 4.0 International - CC BY 4.0. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright 
owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduc-
tion is permitted which does not comply with these terms.

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7 J Global Clinical Engineering Vol.6 Issue 4: 2024

INTRODUCTION

Stereotactic radiosurgery is minimally invasive or 
non-invasive type of external beam radiation therapy that 
operates behind the principle of using focal technique to 
deliver high radiation doses in one or few fractions by 
the help of multiple convergent beams of high energy 
photons to distinct small target volumes while sparing 
healthy surrounding tissues.1,2  These treatments can be 
delivered using the Cyberknife, Gamma Knife, Novalis, 
Proton and LINAC-based systems.3 LINAC-based systems 
for SRS are increasing and gaining ground in many centers. 
Nonetheless, the prescription isodose levels differ among 
different institutions.4

Utilizing flattening filter-free (FFF) beams and volu-
metric modulated arc therapy (VMAT), linear accelerator 
(LINAC)-based SRS enables the delivery of intricate dose 
distributions within a shorter timeframe. With only a 
few fractions, any slight deviation from the target could 
majorly affect tumour control. Thus, the accurate local-
ization of targets and adherence to strict mechanical and 
dosimetric tolerances are crucial for precisely delivering 
LINAC-based SRS plans.5,6

The quality assurance (QA) of this LINAC-based SRS 
system is important for fully implementing this advanced 
technique. Mistakes committed in any of the stages in 
the radiotherapy chain may pose detrimental effects 
to patients. While some mistakes can be found through 
pre-treatment dose verification, called patient-specific 
quality assurance (PSQA), others during the acceptance 
and commission stage.7,8

Pre-treatment verification confirms that the treat-
ment dose, position, and volume are as planned. In a 
broader sense, verification assures the quality of treat-
ment implementation. Stereotactic radiosurgery (SRS) is 
a well-established technique that delivers larger doses of 
radiation to small intracranial targets, usually in a single 
session. This therapy has stood the test of time and has 
evolved with technological advances.9 Initially developed 
within a fixed frame system with point-based measurements 
of target coordinates, SRS has progressed to frameless 
systems with image-guided target localization. Dynamic 
modulated arc therapy with the LINAC has also increas-
ingly gained ground in delivering SRS. Considering this, 

it is undoubtedly true that technological advances have 
reduced set-up inaccuracies and uncontrolled errors in 
delivering SRS. However, these innovations have made 
treatment delivery an increasingly complex process, and 
there is an ultimate need for assurance that the exact dose 
is delivered to the right target and that maximal sparing 
of the adjacent normal critical organs is held.3,10

Nowadays, a couple of methods are used for PSQA. 
These include point or transmission dose verification, 3D 
dose reconstruction methods, and other dedicated phan-
toms.11 Dosimeters such as diodes, ionization chambers, 
and radiochromic films are widely used but their area of 
functioning differs. Some may not be ideal for smaller 
fields because of large sensitive volumes.12 

Film dosimetry is commonly used for pre-treatment 
verifications. However, mistakes can occur during the 
calibration and reading process.13 While a diode detector 
is appropriate for small field measurements as mostly 
used in SRS, in big fields, it over-response due to high Z 
material.14,15 A recent study found that synthetic diamond 
detectors performed well when measuring point doses 
in stereotactic radiation beams. However, single-element 
detectors also offer limited information regarding the 
dose distribution.13

In this study, the authors aimed to establish congru-
ence between LINAC-based SRS VMAT Plans at different 
prescription isodose levels to measurement done with 
the Delta4 Phantom+ and to validate the use and appro-
priateness of this phantom for pre-treatment verification.

MATERIALS AND METHODS

All Treatment Planning and Phantom measurements 
were performed at the Centro riferimento di Oncologico 
(CRO), Aviano-Italy. The measurements were done on 
Varian TrueBeam LINAC and with the new wireless Delta4 
Phantom+ (Figure 1). 

The treatment plans were generated using the Varian 
Eclipse 15.0 treatment planning system (TPS). Clinically 
accepted VMAT SRS plans made with Computed Tomography 
(CT) images of the Stereotactic End-to-End Verification 
(STEEV) anthropomorphic phantom with six different 
prescription isodose levels (50, 55, 60, 65, 70, and 80), 

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a prescribed dose of 18 Gy in a single fraction and using 
6 MV FFF beam were created. The treatment plans were 
done with five arcs and three different planning target 
volume margins (0 mm, 1 mm, 2 mm).

The Delta4 Phantom+ is a new wireless system that 
allows highly accurate patient-specific QA of advanced 
radiotherapy techniques like IMRT, VMAT, SRS, Halcyon, 
and TomoTherapy. It uses a three-dimensional (3D) de-
tector array with 1069 detectors to assess the full dose 
distribution in the isocentric region, rather than just a 
single planar measurement.16 This comprehensive 3D 
verification ensures the treatment is given as exactly 
planned. The Delta4 Phantom+ comprises two planar 
circuit boards built in an orthogonal crossed array pat-
tern. These boards feature radiation-detecting elements 
of p-type and Si diodes, with a 0.5 cm spacing in the cen-
tral high-resolution region and a 1 cm spacing elsewhere 
(Figure 2).

The high-resolution region of the boards is located in the 
central 6 cm × 6 cm area, while the overall detector plane 
region measures 20 cm × 20 cm. The cylindrical phantom 
is 22 cm in diameter and 4 cm in length. The material is 
composed of PMMA and has a 1.19 g/cm3 of mass density. 
The Delta4 Phantom+ has a dose resolution of 0.1 mGy, 
allowing for precise measurements. It can detect doses 
as low as 1 mGy, without any upper limit. The phantom 
is entirely wireless, without any cable connections. It 
effortlessly transfers data using Wi-Fi and operates on 
battery power, ensuring a seamless and convenient set-
up and usage experience.17

The Varian TrueBeam LINAC is a modern medical linear 
accelerator that revolutionizes radiotherapy treatment. 
It has photon energies of 6, 10, and 15 MV, 6 and 10 FFF, 
and electron energies of 6, 9, 12, 15, and 18 MeV. It has a 
round edge, millennium multi-leaf collimator (MLC) with 
middle 20 pairs of width 0.5 cm, peripheral 20 pairs of 
width 1 cm, and an enhanced dynamic wedge. MV imaging 
has 2.5 MV photon energy; in addition, it has kV CBCT and 
a-Si 1200 portal imaging. This allows for image-guided 
radiotherapy and various high-end treatments like SRS 
and Stereotactic Body Radiotherapy (SBRT).18

The treatment plans were modelled onto the Delta4 
Phantom+ CT scan within the TPS for dose calculation. 
The dose distribution was recalculated, and the planning 
data, including the original plan’s beam parameters, were 
the same. These plans were then transferred to the True 
beam LINAC and delivered (Figure 3). 

The Delta4 Phantom+ software is an integral component 
of the Delta4 Phantom+ system. The software provides 
an intuitive and easy-to-navigate interface, allowing users 
to quickly set up and perform measurements. It supports 
DICOM structure import functions, allowing for seamless 
integration with existing treatment planning systems (TPS). 
The Delta4 software enables real-time acquisition of dose 
distribution data during treatment delivery, providing 
instant feedback on treatment accuracy. It offers a range 
of tools to analyze the disparities between measurement 
and calculated TPS dose effectively. 17 An analysis utilized 
the key parameters distance to agreement (DTA), dose 
agreement (DA), and the gamma pass rate. The concept 
of gamma analysis was initially proposed by Low et al.19 

FIGURE 1. The set-up position of the Delta4 Phantom+ on the 
couch of the Truebeam LINAC.

FIGURE 2. The operation of the Delta4 Phantom+ showing the 
interior of the radiation-detecting elements.16

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as a means to compare dose distributions that have been 
calculated and measured quantitatively. This utilizes the 
physical distance and dose difference, then normalizes 
them based on the acceptability criteria.20

The DTA, dose deviation (DD), and gamma-index pass-
ing rates were all calculated by the software.19 The criteria 
for acceptance used in this center was DTA of 3 mm, dose 
difference of 3%, and the gamma-index passing rate of 
95% and 90% for IMRT and VMAT SRS, respectively based 
on the AAPM TG-218 action limit8 but in this study a 2% 
dose difference, 2 mm DTA and the gamma-index passing 
rate of 95% were used. Isocenteric set-up position was 
used for the Delta4 Phantom+ in measurement. A four-
field box technique measuring 10 × 10 cm2 was measured 
for the correction factor.16

RESULTS

The analysis of all plans included using the three most 
suitable parameters: the DA (with a limit of 2%), DTA 
(with a limit of 2 mm), and gamma passing rate.

Table 1 summarizes the results of the gamma passing 
rate, distance to an agreement, and DD of all plans with 
the different prescription isodose levels. Overall, in all 
cases, excellent agreement was seen between the mea-
surement and calculation of TPS doses. The minimum 

gamma passing rate was 99.6% and the maximum was 
100%. The gamma passing rate for all plans was higher 
than 95% using 2%/2 mm DD/DTA. Our criteria of 95% 
for the gamma-index was met for all plans with all the 
different prescription isodose levels used. The correction 
factor was found to be 1.01.

FIGURE 3. Truebeam LINAC monitor interface during measurement.

TABLE 1. Kappa values for qualitative variables showing good 
agreement between two devices.

Assessment 
Parameters

Margin 
Used   Prescription Isodose Level

 50  55  60  65   70  80

Gamma-
Index 

passing rate
2%/2 mm

0 mm 99.7% 99.8% 99.9% 99.9%  100% 100%

1 mm 99.6% 99.7% 99.9% 99.7% 99.8% 100%

2 mm 99.9% 100% 100% 100%  99.8% 99.8%

Dose 
deviation 

(DD)

0 mm 76.0% 76.0% 79.1% 80.3%  81.1% 83.4%

1 mm 76.1% 76.1% 79.5% 80.7%  81.5% 83.7%

2 mm 76.2% 76.2% 79.9% 80.9%  81.7% 83.9%

Dose to time 
agreement 

0 mm 100% 100% 100% 100%  100% 100%

1 mm  100% 100% 100% 100%  100% 100%

2 mm  100% 100% 100% 100%  100% 100%

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DISCUSSION

In this study, the use and suitability of the wireless 
Delta4 Phantom+ were assessed for treatment verification 
of LINAC-based SRS plans made with different prescrip-
tion isodose levels. We compared measurements made 
with phantom and treatment planning dose. We found 
the wireless Delta4 Phantom+ as an easily set-up device 
with minimal positional errors that provides consistent 
and comprehensive QA suitable for SRS plans. Its func-
tionality is identical to the plug-in Delta4 Phantom+ with 
a few exceptions.21 The wireless system, real-time results, 
waterproof construction, and ease of use make it well-
suited to measuring small fields and composite SRS plans.

Delta4’s first calibration and commissioning procedure 
must be completed with rigorous and precise measurements 

to assure patient-specific QA testing accuracy. It enables 
complete analysis of data and a quicker approach to con-
duct measurements without the need for additional QA 
systems. Measurements are taken on the phantom’s two 
planes, and the software generates a 3D dose distribution 
using an interpolation approach16 (Figure 4).

There is documented evidence of the use of other de-
tectors in SRS, such as ionization chambers, alanine pel-
lets, plastic scintillators, Sun Nuclear Corporation (SNC) 
ArcCHECK, SNC SRS MapCHECK, IBA Matrixx Resolution, 
electronic portal imaging device (EPID) and IBA myQA 
SRS but their scope of operation varies.6,22

The gamma-index is a valuable tool in dosimetric veri-
fication analysis, allowing for a comparison between the 
TPS plan and the measurement (Figure 5).

FIGURE 4. The Delta4 Phantom+ software displaying the result. The absolute dosage is shown in two diode arrays in three di-
mensions on the top panel, with color coding used to indicate the dose (yellow arrow).

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It provides a metric to assess the level of agreement 
in dose. It is commonly utilized for PSQA. The minimum 
gamma pass rate was 99.6%, and the maximum was 100%. 
The gamma passing rate was above 95% for all plans as 
seen in Table 1. Dose goals were also achieved. Develop-
ing a center-specific protocol is crucial, as the treatment 
planning and set-up influence the gamma-index. Various 
factors can impact the final result, such as the detector’s 
type and sensitivity, TPS algorithm, LINAC output, and 
clinical judgment of dose tolerance level.23

It is important to mention that the DTA and DD criteria 
utilized for gamma analysis are not entirely independent. 
They have a connection to the dose gradient factor. It 
is widely accepted that a passing rate of 90% with a 3 
mm/3% clinical significance is commonly used for most 

highly advanced treatment techniques.24 This study used 
a different gamma passing rate of 95% with a 2 mm/2% 
due to the sharp dose gradient in SRS. However, should 
our gamma-index passing rate be less than 95%, further 
verification would be necessary with any of the other de-
tectors such as gafchromic film. According to Nelms et al., 
gamma passing rates using the criterion of 3mm/3% are 
insensitive to clinically meaningful patient dose mistakes 
on a field-by-field basis.25

Sadagopan et al. validated the accuracy and reproduc-
ibility of the Delta4 device by comparing its results to 
measurement with film and an ion chamber.26 Similarly, 
Bedford et al. found that Delta4 demonstrated a slightly 
stronger correlation between calculated and measured 
doses than the film.27 This may be due to the absolute 

FIGURE 5. The Delta4 Phantom+ software displaying three histograms: distance to agreement, dose deviation, and gamma-index.

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nature of Delta4 measurements in contrast to the relative 
nature of film dosimetry.

Our measured pass rates were comparable with those 
of other detectors using the same pass criteria when 
used for treatment verification for VMAT Plans. The 
minimum gamma passing rate in our study was higher 
when compared to EBT-XD Film 96.70%, EPID 95.93%, 
SRSMapCHECK 96.76%, and myQA SRS 97.91% using the 
same passing criteria 2%/2mm.6 Furthermore, in a study 
by Desai et al.,the Delta4 Phantom+’s performance was 
evaluated by measuring 36 clinical cases using a ViewRay 
MRIdian linac.28 The findings were identical to those ob-
tained utilizing a Sun Nuclear ArcCHECK. Both devices met 
the institution’s 95% pass rate for a 3%/3 mm gamma 
requirement. Still, the use of 2%/2 mm gamma passing 
rates revealed subtle variances among the devices, with 
the Delta4+ being a little superior in terms of the results.28

Applying 2%/2 mm as a gamma parameter provided 
excellent sensitivity and minimum fluctuation. The de-
tector’s resolution allows for good visualization of the 
gamma distribution graphically on the software. This is 
a precious visual tool for identifying regions of overdose 
and underdose.29

Our final measured gamma pass rates may be influ-
enced by some factors such as the TrueBeam LINAC out-
put variability, user configuration, and detector settings. 
However, it is challenging to separate these factors from 
the final findings. Moreover, selecting an SRS QA detector 
is contingent upon several elements that vary between 
institutions. These considerations include prior expertise, 
financial resources, user-friendliness, and the sensitivity 
and specificity requirements that align with the institu-
tion’s unique SRS QA criteria.2,6 Hence, it is important to 
interpret the gamma pass rates presented in this study as 
a validation of the Delta4 Phantom+ as suitable for SRS 
treatment verifications rather than as a direct method 
for comparing it with the other detectors. Furthermore, 
although we recommend using 2%/2 mm because of the 
great degree of agreement our investigation was able to 
attain, other tight gamma parameters such as 2%/1 mm 
or 1%/1 mm could be explored due to the high dosimetric 
accuracy of stereotactic treatments.8

CONCLUSION

The Delta4 Phantom+ and software system provide 
efficient set-up, precise real-time measurement, and 
comprehensive three-dimensional analysis, making it 
well-suited for the intricate nature of modulated irradia-
tion such as VMAT SRS on the LINAC. The findings suggest 
that good agreement between measurement and TPS was 
achieved irrespective of the prescription isodose and 
planning target volume margins used. The use of Delta4 
Phantom+ demonstrates efficacy and efficiency in PSQA. 
Accuracy is crucial in every aspect of treatment delivery 
for SRS plans; however, despite meeting the gamma-index 
rate used, we recommend a stricter passing rate for VMAT 
SRS Plans. The comparison of Delta4 Phantom+ with 
other QA verification systems was not conducted due to 
time constraints and the unavailability of different QA 
systems in the department. There is potential for further 
expansion of the work.

CONFLICTS OF INTEREST STATEMENT

The authors declare that they have no conflicts of 
interest.

ACKNOWLEDGMENT

We want to express our sincere gratitude to all staff 
at the Medical Physics department of Centro riferimento 
di Oncology (CRO) in Aviano-Italy who supported data 
collection and made my research visit fruitful.

REFERENCES

1. Fiagbedzi, E., Hasford, F., Tagoe, S.N., et al. Radio-
therapy infrastructure for brain metastasis treatment 
in Africa: practical guidelines for implementation of 
a stereotactic radiosurgery (SRS) program. Health 
Technol. 2023;13:893–904.  https://doi.org/10.1007/
s12553-023-00799-3.

2. Korreman, S., Medin, J., Kjær-Kristoffersen, F. Do-
simetric verification of RapidArc treatment deliv-
ery. Acta Oncol. 2009;48(2):185–191. https://doi.
org/10.1080/02841860802287116.

http://www.globalce.org
http://globalce.org
http://globalce.org
https://doi.org/10.1007/s12553-023-00799-3
https://doi.org/10.1007/s12553-023-00799-3
https://doi.org/10.1080/02841860802287116
https://doi.org/10.1080/02841860802287116


13 J Global Clinical Engineering Vol.6 Issue 4: 2024

3. Padilla, L. and Palta, J.R. Overview of Technologies for 
SRS and SBRT Delivery. In Stereotactic Radiosurgery 
and Stereotactic Body Radiation Therapy (SBRT); Heron, 
D.E. and Huq, M.S. eds. Springer: Berlin, Germany; 
2018, pp. 73–101.

4. Hellerbach, A., Eichner, M., Rueß, D., et al. Impact of pre-
scription isodose level and collimator selection on dose 
homogeneity and plan quality in robotic radiosurgery. 
Strahlentherapie und Onkol. 2022;198(5):484–496. 
https://doi.org/10.1007/s00066-021-01872-4.

5. Kim, J., Park, S.Y., Kim, H.J., et al. The sensitivity of 
gamma-index method to the positioning errors of 
high-definition MLC in patient-specific VMAT QA 
for SBRT. Radiat Oncol. 2014;9(1):1–12. https://doi.
org/10.1186/1748-717X-9-167.

6. James, S., Al-Basheer, A., Elder, E., et al. Evaluation 
of commercial devices for patient specific QA of ste-
reotactic radiotherapy plans. J Appl Clin Med Phys. 
2023;24(8):1–11. https://doi.org/10.1002/acm2.14009.

7. Solberg, T.D., Balter, J.M., Benedict, S.H., et al. Quality 
and safety considerations in stereotactic radiosurgery 
and stereotactic body radiation therapy: Executive 
summary. Pract Radiat Oncol. 2012;2(1):2–9. https://
doi.org/10.1016/j. prro.2011.06.014.

8. Xia, Y.Q., Adamson, J., Zlateva, Y., et al. Physics investi-
gation Application of TG-218 action limits to SRS and 
SBRT pre-treatment patient specific QA. J Radiosurgery 
SBRT. 2020;7(2):135–147.

9. Loo, M., Clavier, J.B., Khalifa, J.A., et al. Dose-response 
effect and dose-toxicity on stereotactic radiotherapy for 
brain metastases: A review. Cancers. 2021;13(23):1–22. 
https://doi.org/10.3390/cancers13236086.

10. Milano, M.T., Grimm, J., Niemierko, A., et al. Single- 
and Multifraction Stereotactic Radiosurgery Dose/
Volume Tolerances of the Brain. Int J Radiat Oncol Biol 
Phys. 2021;110(1):68–86. https://doi.org/10.1016/j.
ijrobp.2020.08.013.

11. Huang, Z., Qiao, J., Yang, C., et al. Quality Assurance 
for Small-Field VMAT SRS and Conventional-Field 
IMRT Using the Exradin W1 Scintillator. Technol 
Cancer Res Treat. 2021;20(270):1–7. https://doi.
org/10.1177/15330338211036542.

12. Ahmed, S., Zhang, G., Moros, E.G., et al. Comprehensive 
evaluation of the high-resolution diode array for SRS 
dosimetry. J Appl Clin Med Phys. 2019;20(10):13–23. 
https://doi.org/10.1002/acm2.12696.

13. Stepanek, C.J., Haynes, J.A., Fletcher, S. Evaluation of a 
complementary metal oxide semiconductor detector as 
a tool for stereotactic body radiotherapy plan quality 
assurance. Phys Imaging Radiat Oncol J. 2023;25(100418). 
https://doi.org/10.1016/j.phro.2023.100418.

14. Koper, T., Kowalik, A., Adamczyk, S. The semiconduc-
tor diode detector response as a function of field size 
and beam angle of high-energy photons. Rep Pract 
Oncol Radiother. 2017;22(3):193–200. http://dx.doi.
org/10.1016/j.rpor.2016.12.004.

15. Atuwo-Ampoh, D.V., Manson, E.N., Schandorf, C., et al. In 
Vivo Dosimetry Using a Flat Surface Sun Nuclear Cor-
poration Diode in 60 co Beams for Some Radiotherapy 
Treatments in Ghana. Iran J Med Phys. 2019;16:329–335. 
https://doi.org/10.22038/ijmp.2018.29705.1324.

16. Delta4 Phantom+: The Fastest and most accurate 4D 
verification system. Available online: https://delta4fam-
ily.com/products/measurement-phantoms/phantom/.

17. Delta4 Phantom+ wireless Phantom. Available online: 
https://pdf.medicalexpo.com/pdf/scandidos/delta-
4-phantom-wireless-phantom/101140-157661.html.

18. Dutta, B., Goswami, S., Moran, S., et al. Commissioning 
and performance evaluation of varian truebeam linear 
accelerator. J Radiat Med Trop. 2023;4(1):25. https://
doi.org/10.4103/jrmt.jrmt_11_22.

19. Low, D.A. Gamma dose distribution evaluation tool. 
J Phys Conf Ser. 2010;250:349–359. https://doi.
org/10.1088/1742-6596/250/1/012071.

20. Song, J.H., Kim, M.J., Park, S.H., et al. Gamma analysis 
dependence on specified low-dose thresholds for 
VMAT QA. J Appl Clin Med Phys. 2015;16(6):263–272.  
https://doi.org/10.1120/jacmp.v16i6.5696.

21. Srivastava, R.P. and De Wagter, C. Clinical experience 
using Delta 4 phantom for pre-treatment patient-
specific quality assurance in modern radiotherapy. 
J Radiother Pract. 2019;18(2):210–214. https://doi.
org/10.1017/S1460396918000572.

http://www.globalce.org
http://globalce.org
http://globalce.org
https://doi.org/10.1007/s00066-021-01872-4
https://doi.org/10.1186/1748-717X-9-167
https://doi.org/10.1186/1748-717X-9-167
https://doi.org/10.1002/acm2.14009
https://doi.org/10.1016/j. prro.2011.06.014
https://doi.org/10.1016/j. prro.2011.06.014
https://doi.org/10.3390/cancers13236086
 https://doi.org/10.1016/j.ijrobp.2020.08.013
 https://doi.org/10.1016/j.ijrobp.2020.08.013
https://doi.org/10.1177/15330338211036542
https://doi.org/10.1177/15330338211036542
https://doi.org/10.1002/acm2.12696
https://doi.org/10.1016/j.phro.2023.100418
http://dx.doi.org/10.1016/j.rpor.2016.12.004
http://dx.doi.org/10.1016/j.rpor.2016.12.004
https://doi.org/10.22038/ijmp.2018.29705.1324
https://delta4family.com/products/measurement-phantoms/phantom/
https://delta4family.com/products/measurement-phantoms/phantom/
https://pdf.medicalexpo.com/pdf/scandidos/delta-4-phantom-wireless-phantom/101140-157661.html
https://pdf.medicalexpo.com/pdf/scandidos/delta-4-phantom-wireless-phantom/101140-157661.html
https://doi.org/10.4103/jrmt.jrmt_11_22
https://doi.org/10.4103/jrmt.jrmt_11_22
https://doi.org/10.1088/1742-6596/250/1/012071
https://doi.org/10.1088/1742-6596/250/1/012071
https://doi.org/10.1120/jacmp.v16i6.5696
https://doi.org/10.1017/S1460396918000572
https://doi.org/10.1017/S1460396918000572


J Global Clinical Engineering Vol.6 Issue 4: 2024 14

22. Sasaki, M., Sugimoto, W., Ikushima, H. Simplification 
of head and neck volumetric modulated arc therapy 
patient-specific quality assurance, using a Delta4 
PT. Rep Pract Oncol Radiother. 2020;25(5):793–800. 
https://doi.org/10.1016/j.rpor.2020.07.004.

23. Das, S., Kharade, V., Pandey, V.P., et al. Gamma Index 
Analysis as a Patient-Specific Quality Assurance Tool for 
High-Precision Radiotherapy: A Clinical Perspective of 
Single Institute Experience. Cureus. 2022;14(10):e30885. 
https://doi.org/10.7759/cureus.30885.

24. Li, H., Dong, L., Zhang, L.F., et al. Toward a better 
understanding of the gamma index: Investigation of 
parameters with a surface-based distance methoda. 
Med Phys. 2011;38(12):6730–6741. https://doi.
org/10.1118/1.3659707.

25. 25.Nelms, B.E., Zhen, H., Toḿ, W.A. Per-beam, planar 
IMRT QA passing rates do not predict clinically relevant 
patient dose errors. Med Phys. 2011;38(2):1037–1044. 
https://doi.org/10.1118/1.3544657.

26. Sadagopan, R., Bencomo, J.A., Martin, R.L., et al. 
Characterization and clinical evaluation of a novel 
IMRT quality assurance system. J Appl Clin Med Phys. 
2009;10(2):104–119. https://doi.org/10.1120/jacmp. 
v10i2.2928.

27. Bedford, J.L., Lee, Y.K., Wai, P., et al. Warrington AP. 
Evaluation of the Delta 4 phantom for IMRT and VMAT 
verification. Phys Med Biol. 2009;54(9):167–176. 
https://doi.org/10.1088/0031-9155/54/9/N04.

28. Desai, V., Bayouth, J., Smilowitz, J., et al. A clinical 
validation of the MR-compatible Delta4 QA system 
in a 0.35 tesla MR linear accelerator. J Appl Clin Med 
Phys. 2021;22(4):82–91. https://doi.org/10.1002/
acm2.13216.

29. Woon, W., Ravindran, P.B., Ekanayake, P., et al. A study 
on the effect of detector resolution on gamma index 
passing rate for VMAT and IMRT QA. J Appl Clin Med 
Phys. 2018;19(2):230–248. https://doi.org/10.1002/
acm2.12285.

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https://doi.org/10.1002/acm2.13216.
https://doi.org/10.1002/acm2.12285
https://doi.org/10.1002/acm2.12285

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