Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
Dosime ic Ou comes o IMRT and VMAT in Head and Neck
Radio he apy: Re ospec i e Ins i u ional Expe ience.
Sunil Kuma *1, Rashmi Yada 2
*Co espondence o: Sunil Kuma , India.
Copy igh .
© 2025 Sunil Kuma This is an open access a icle dis ibu ed unde he C ea i e Commons A ibu ion
License, which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal
wo k is p ope ly ci ed.
Recei ed: 03 Sep 2025
Published: 11 Sep 2025
MAR Oncology and Hema ology (2025) 5:08
Resea ch A icle
Sunil Kuma , MAR Oncology and Hema ology (2025) 5:08.
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
In oduc ion
Head and neck cance s (HNC), encompassing malignancies o he o al ca i y, o opha ynx, hypopha ynx, and
la ynx, ep esen app oxima ely 4% o global cance diagnoses and a e a leading cause o cance - ela ed
mo bidi y and mo ali y [1]. Radio he apy is a co ne s one o HNC managemen , o en deli e ed as de ini i e
ea men o adju an he apy alongside su ge y and chemo he apy [2, 3].
Abs ac
Backg ound: Head and neck cance s (HNC) pose signi ican challenges o adio he apy due
o hei p oximi y o c i ical o gans-a - isk (OARs). While in ensi y-modula ed adia ion
he apy (IMRT) emains he gold s anda d o dose con o mi y, olume ic modula ed a c
he apy (VMAT) has eme ged as a p omising ad ancemen , o e ing dynamic a c-based
deli e y wi h po en ial gains in e iciency and dosime ic p ecision.
Objec i e: To compa e he dosime ic pe o mance o IMRT and VMAT in HNC adio he apy,
ocusing on a ge co e age, OAR spa ing, ea men e iciency, and plan quali y.
Me hods: In his e ospec i e s udy, 40 pa ien s wi h his ologically con i med head and neck
squamous cell ca cinoma (HNSCC) unde wen dual planning (IMRT and VMAT) using
iden ical a ge olumes and dose cons ain s. Dosime ic pa ame e s including PTV co e age
(D95%), mean/maximum OAR doses, homogenei y index (HI), con o mi y index (CI), and
moni o uni s we e analyzed. S a is ical compa isons used pai ed - es s (SPSS 26).
Resul s: Bo h modali ies achie ed clinically accep able PTV co e age. VMAT demons a ed
supe io dose con o mi y (CI: 1.16 s. 1.18, p < 0.05) and homogenei y (HI: 0.050 s. 0.056, p
< 0.05) compa ed o IMRT. VART signi ican ly educed maximum doses o he spinal co d
(27.61 s. 28.71 Gy, p < 0.05) and PRV co d (31.39 s. 32.58 Gy, p < 0.05), while lowe ing
mean dose o mandible (62.13 s. 65.13 Gy, p < 0.05) and mean o skin Dmax (65.01 s. 65.81
Gy, p < 0.05).
Conclusion: VMAT ou pe o med IMRT in HNC adio he apy, deli e ing supe io dose
homogenei y, con o mi y, and OAR spa ing while signi ican ly sho ening ea men ime.
These ad an ages posi ion VMAT as he p e e ed modali y o balancing e icacy wi h educed
oxici y isks in clinical p ac ice.
Sunil Kuma , MAR Oncology and Hema ology (2025) 5:08.
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
Deli e ing cu a i e adia ion doses in HNC is complica ed by he in ica e ana omy o he egion, whe e
umo s equen ly abu c i ical s uc u es such as he spinal co d, pa o id glands, mandible, pha yngeal
cons ic o s, and skin [4]. Excessi e i adia ion o hese o gans-a - isk (OARs) can lead o debili a ing
oxici ies, including xe os omia, dysphagia, os eo adionec osis, and neu ocogni i e de ici s, p o oundly
a ec ing long- e m pa ien quali y o li e [5–7].
In ensi y-modula ed adia ion he apy (IMRT) eme ged as a ans o ma i e ad ancemen o e con en ional
echniques like 3 D con o mal adio he apy, enabling shaped dose dis ibu ions ha con o m o i egula umo
geome ies while spa ing adjacen OARs [8,9]. Clinical s udies ha e alida ed IMRT’s abili y o educe
oxici ies, pa icula ly xe os omia, h ough p ecise spa ing o sali a y glands [10–12]. Volume ic modula ed
a c he apy (VMAT), a mo e ecen inno a ion, builds upon IMRT p inciples by deli e ing adia ion
con inuously du ing gan y o a ion, dynamically modula ing mul ilea collima o (MLC) posi ions, dose a e,
and gan y speed [13]. This app oach p omises inc ease ea men e iciency ia sho e deli e y imes while
main aining o imp o ing dosime ic quali y [14–16].
Despi e hese ad ances, he compa a i e me i s o IMRT and VMAT in HNC emain deba ed. While some
s udies epo ha VMAT achie es compa able o supe io OAR spa ing and a ge co e age wi h educed
ea men imes [17–19], o he s highligh conce ns abou inc eased low-dose adia ion exposu e o heal hy
issues (“low-dose ba h”), po en ially ele a ing isks o seconda y malignancies o la e oxici ies [20,21].
These disc epancies unde sco e he need o obus , clinically g ounded compa isons o guide modali y
selec ion.
This s udy le e ages ins i u ional planning da a o pe o m a comp ehensi e dosime ic e alua ion o IMRT
and VMAT in HNC, assessing a ge co e age, OAR spa ing, dose homogenei y/con o mi y, and deli e y
e iciency. By add essing con lic ing e idence in he li e a u e, we aim o in o m e idence-based clinical
decision-making in an e ol ing he apeu ic landscape.
Ma e ials and Me hods
S udy Design and Pa ien Selec ion
This e ospec i e dosime ic analysis included 40 consecu i e pa ien s wi h his ologically con i med
squamous cell ca cinoma o he head and neck (HNSCC) mos ly locally ad ance s age, ea ed a he Hind
Ins i u e o Medical Sciences, Ba abanki, be ween Janua y 2023 and Ma ch 2024.
Inclusion C i e ia:
His ologically p o en Head and neck squamous cell ca cinoma (o al ca i y, o opha ynx, hypopha ynx, o
la ynx).
Ka no sky Pe o mance S a us (KPS) ≥70.
Sunil Kuma , MAR Oncology and Hema ology (2025) 5:08.
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
No mal hema ologic, hepa ic, and enal unc ion.
Exclusion C i e ia:
P io o synch onous malignancy.
His o y o head and neck su ge y.
P e ious adio he apy o he head and neck egion.
Dis an me as ases (con i med by PET-CT/con as -enhanced CT)
E hical App o al
The s udy p o ocol was app o ed by he Ins i u ional E hics Commi ee o Hind In i u e o Medical Sciences
Ba abanki (App o al No. [Inse Numbe ]), adhe ing o he Decla a ion o Helsinki.
Imaging and Ta ge Delinea ion
Simula ion:
Pa ien s unde wen con as -enhanced CT simula ion (Siemens SOMATOM Go Now, 3 mm slice
hickness) in a supine posi ion wi h a he moplas ic immobiliza ion mask.
Head and neck posi ioning was s anda dized using a cus omized head es o main ain neu al neck alignmen .
Ta ge Volumes (ICRU 83 [22]):
GTV: G oss umo delinea ed using clinical examina ion and imaging (CT/MRI/PET-CT usion).
CTV: GTV + 5mm mm ma gin (ana omical bounda ies espec ed) o encompass mic oscopic disease.
PTV: CTV + 5 mm iso opic ma gin o se up unce ain ies.
O gans-a -Risk (OARs):
Con ou ed pe ICRU 62 guidelines: spinal co d, spinal co d planning isk olume (PRV; 2 mm ma gin),
bila e al pa o id/submandibula glands, mandible, lips, hy oid, esophagus, skin (3 mm dep h), and pha yngeal
cons ic o s.
T ea men Planning
IMRT Planning:
Beam A angemen : 9 coplana ixed-gan y beams (angles: 200°, 240°, 280°, 320°, 0°, 40°, 80°, 120°,
160°). (Fig.1)
Op imiza ion: Va ian Eclipse™ ( 16.1) wi h Pho on Op imize (PO) and Analy ical Aniso opic Algo i hm
(AAA, g id size 2.5 mm).
VMAT Planning:
A c Design: 2 ull a cs (179°–181°, clockwise/coun e clockwise) wi h dynamic MLC (Millennium 120-lea ),
Sunil Kuma , MAR Oncology and Hema ology (2025) 5:08.
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
a iable dose a e (25–600 MU/min), and gan y speed (0.5–4.8°/s). (Fig.1)
Sha ed Op imiza ion Objec i es:
PTV Co e age: D95% ≥ 95% o p esc ip ion dose (66 Gy).
OAR Cons ain s:
Spinal co d/PRV: Dmax ≤45 Gy.
Pa o id glands: Dmean ≤26 Gy.
Mandible: Dmax ≤70 Gy.
Fig 1: A-9 Field IMRT Plan, B-3 ull a ch(VMAT Plan)
Fig 2: Colo wash compa ison IMRT Vs VMAT
Sunil Kuma , MAR Oncology and Hema ology (2025) 5:08.
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
Fig 3: DVH compa ison IMRT Vs VMAT plan
Plan E alua ion
Dosime ic Pa ame e s:
PTV Co e age: D2%, D50%, D95%, D98%.
Plan Quali y:
Homogenei y Index (HI): HI= (D2%−D98%)/D50% .
Con o mi y Index (CI): (Volume co e ed by p esc ip ion dose) / (PTV olume)
OAR Doses: Dmean (pa o ids, submandibula glands), Dmax (spinal co d, mandible).
1. T ea men E iciency:
Moni o Uni s (MUs) pe ac ion.
S a is ical Analysis
Con inuous a iables (HI, CI, OAR doses, MUs) we e compa ed using pai ed S uden ’s - es s (SPSS 30.0,
IBM Co p.).
No mali y was con i med ia Shapi o-Wilk es .
S a is ical signi icance: p<0.05.
Resul s
Ta ge Volume Co e age
Bo h IMRT and VMAT p o ided adequa e PTV co e age, wi h compa able mean D95% alue (p = 0.12).
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
Howe e , VMAT demons a ed s a is ically signi ican imp o emen s in dose homogenei y (HI: 0.0504
s. 0.0557, p = 0.0002) and con o mi y (CI: 1.1659 s. 1.1849, p = 0.0423). (Table 1)
O gan-a -Risk (OAR) Spa ing
VMAT plans demons a ed supe io spa ing o c i ical s uc u es, especially he PRV (31.39 s. 32.58 Gy, p <
0.05), Spinal co d (27.61 s. 28.71 Gy, p < 0.05). (Table 2)
T ea men E iciency
VMAT signi ican ly educed Moni o Uni s compa ed o IMRT. (Table 3)
Table 1. Ta ge Volume Dosime ic Pa ame e s (mean ± SD)
Pa ame e s
IMRT
VMAT
p- alue
PTV D95%
157.7±99.20
155±99.20
0.12
PTV Dmean
65.2±1.91
66.08±0.38
0.08
D2%
67.32±0.47
67.19±0.41
0.07
D98%
63.64±0.33
63.8±0.60
0.02*
Homogenei y Index (HI)
0.05±0.006
0.05±0.009
0.002*
Con o mi y Index (CI)
1.18±0.09
1.16±0.07
0.04*
*Signi ican a p<0.05
Table 2. OAR Dose Compa ison (mean ± SD)
OAR
IMRT
VMAT
p- alue
PRV co d
32.58±2.59
31.39±4.37
0.03*
Spinal Co d
28.71±2.22
27.61±3.0
0.02*
Ipsila e al Pa o id
28.40±4.39
28±4.08
0.08
Con ala e al Pa o id
25.81±4.30
25.36±3.92
0.13
Pa o id mean
26.97±4.10
26.65±3.72
0.19
Pa o id Dmax
63.50±5.08
63.45±4.97
0.45
Ipsila e al SMG
57.83±6.71
57.15±8.71
0.21
Con ala e al SMG
49.49±8.8
51.59±8.51
0.002*
Mandible Dmax
65.13±5.54
62.98±9.66
0.04*
Skin Dmax
62.81±3.57
65.01±4.43
0.04*
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
*Signi ican a p<0.05
Table 3. T ea men Deli e y E iciency
Pa ame e
IMRT
VMAT
p- alue
Moni o Uni s (MU mean ± SD )
1495.1±210.97
654.5±50.7
1.5
*Signi ican a p<0.05
Discussion
This s udy demons a es ha VMAT achie es supe io dosime ic pe o mance compa ed o IMRT in head
and neck adio he apy, o e ing enhanced OAR spa ing, imp o ed dose con o mi y/homogenei y, and
g ea e ea men e iciency—wi hou comp omising a ge co e age. These ad an ages a e pa icula ly
ele an o complex cases equi ing bila e al neck i adia ion o la ge ea men olumes, whe e p ecision and
no mal issue p o ec ion a e c i ical.
Key Dosime ic Ad an ages o VMAT
Imp o ed Con o mi y & Homogenei y
The signi ican ly lowe Con o mi y Index (CI) (1.1659 s. 1.1849, p = 0.04) e lec s VMAT’s abili y o
igh ly sculp dose a ound i egula PTV geome ies, minimizing exposu e o adjacen heal hy issues. This
p ecision is especially aluable in head and neck cance s, whe e umo s o en encase c i ical s uc u es [6, 7].
The be e Homogenei y Index (HI) (0.0504 s. 0.0557, p = 0.0002) indica es a mo e uni o m PTV dose
dis ibu ion, educing ho spo s linked o acu e oxici ies and impai ed issue epai [13, 14].
C i ical OAR Spa ing
Spinal Co d & PRV Co d: VMAT signi ican ly educed doses (spinal co d: 27.61 s. 28.71 Gy, p = 0.02;
PRV co d: 31.39 s. 32.58 Gy, p = 0.03), po en ially lowe ing he isk o adia ion-induced myelopa hy—a
c ucial conside a ion o pa ien s ecei ing high cumula i e doses [15, 16].
Mandible & Skin: Reduc ions in mandibula dose (62.13 s. 65.13 Gy, p = 0.04) may mi iga e
os eo adionec osis isk, while lowe skin doses (65.01 s. 65.81 Gy, p = 0.04) could educe de ma i is and la e
Esophagus mean
21.13±9.06
20.26±8.16
0.14
Lip mean
23.49±10.65
23.72±9.71
0.32
Thy oid mean
59.25±5.56
48.04±5.56
0.16
Pha angeal Cons ic o s
46.93±6.68
47.1±7.06
0.37
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Sunil Kuma . (2025). Dosime ic Ou comes o IMRT and VMAT in Head and Neck Radio he apy:
Re ospec i e Ins i u ional Expe ience. MAR Oncology and Hema ology. (2025) 5:08
ib osis [29, 30].
T ea men E iciency
VMAT hal ed moni o uni s (654.5 s. 1495.1 MU, p < 0.001), sho ening deli e y ime. This enhances
pa ien com o , educes in a ac ion mo ion e o s, and imp o es clinic h oughpu [19, 20].
Clinical Implica ions
While la ge coho s udies (e.g., Algouneh e al. [24]) epo compa able su i al ou comes be ween VMAT
and IMRT, he dosime ic bene i s o VMAT—coupled wi h wo k low e iciencies—sugges i may o e a
supe io he apeu ic a io (maximizing umo con ol while minimizing oxici y). Howe e , planne
expe ise and ins i u ional p o ocols emain pi o al o achie ing op imal esul s.
Limi a ions & Fu u e Di ec ions
This s udy is a dosime ic analysis; clinical ou comes (e.g., oxici y a es, umo con ol) we e no
assessed.
P ospec i e ials compa ing oxici y p o iles, quali y o li e, and long- e m e icacy a e needed o
alida e hese indings.
Conclusion
VMAT eme ges as a echnically and clinically ad an ageous e olu ion o IMRT o head and neck
adio he apy, deli e ing supe io OAR spa ing, dose con o mi y, and e iciency while main aining a ge
co e age. I s in eg a ion in o mode n p ac ice aligns wi h he b oade shi owa d p ecision-based, pa ien -
ailo ed adio he apy. Fu u e s udies co ela ing hese dosime ic gains wi h pa ien - epo ed ou comes and
su i al da a will u he solidi y i s ole in op imizing cance ca e.
Re e ences
1. P is e DG, e al. Head and neck cance s, e sion 2.2020, NCCN Clinical P ac ice Guidelines in Oncology.
J Na l Comp Canc Ne w. 2020; 18(7):873-898.
2. Ang KK, e al. Human papilloma i us and su i al o pa ien s wi h o opha yngeal cance . N Engl J Med.
2010; 363(1):24-35.
3. Coope JS, e al. Pos ope a i e concu en adio he apy and chemo he apy o high- isk squamous-cell
ca cinoma o he head and neck. N Engl J Med. 2004; 350(19):1937-1944.
4. Lee N, e al. In ensi y-modula ed adia ion he apy in head and neck cance s: an upda e. Head Neck. 2007;
29(4):387-400.
5. Nu ing CM, e al. Pa o id-spa ing in ensi y modula ed e sus con en ional adio he apy in head and neck
