الفهرس 
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Abstract
Radiation therapy is an important modality for treating most types of
cancer and often is used synergetic with other treatment modalities, such as
surgery , and chemotherapy. Following surgery, radiation is often used to
destroy cancer cells remaining in the site of the disease.
Breast cancer is not one disease but a group of diseases that may affect
breast tissue. Both men and women can get breast cancer, but it is more
common in women worldwide. Some women are at higher risk than others
for this disease due to numerous factors, such as, family medical history, or
due to certain personnel factors changes in their genes.
Breast cancer survival depends on a person‘s diagnosis and treatment.
A main factor in survival is breast cancer stage. People with non-invasive
(stage 0) and early stage invasive (stages I and II) breast cancers have a
better chance of survival than those with later stage cancers (stages III and
IV).
With respect to men, In general, about one man in nine will be
diagnosed with prostate cancer during his life time. In fact, prostate cancer
can be a serious disease, but most men diagnosed with prostate cancer do
not die from it. Prostate cancer begins when cells in the prostate gland start
to grow uncontrollably.
Prostate cancer is potentially curable if detected and treated in the
early stages. There are several treatment options available for prostate
cancer. These treatment options vary according to the stage of the disease
and other medical conditions. Radiotherapy represents one of the most
effective methods for treatment of this disease in men. Radiotherapy is
currently in rapid change, due to rapid achievements in computer
technology which led to the development of new treatment planning and
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120
delivery systems.
Accordingly, this work was conducted aiming to compare between two
techniques already used in radiation therapy, namely; 3DCRT, and IMRT.
Each of these two techniques is characterized by its own advantages. At the
same time, the comparison was based on using numerous parameters
concerning the planning target volume coverage and sparing the organs at
risk of two malignant tumors most common in females and men, i.e., breast
cancer, and prostate cancer.
For this purpose, ten female breast cancer patients, with age range (40
- 55) and ten prostate cancer patients, with age range (66 - 77) from a
hospital in Gharbia Cancer Society (Elsalama Hospital) were recruited in
this study from 1st January 2016 to 30th March2017.
The patients were subjected to a CT scan; the CT data was imported to
the contouring workstation via local area network system. The images from
the CT scanner were transferred to the treatment planning system.
Acquisitioning the contour of the planning target volume (PTV) and
the critical volumes of organs at risk (OARs) according to the Radiation
Therapy Oncology group (RTOG), were estimated. The organs at risk
considered in this work were the lung and heart, for the breast cases, and
rectum, bladder, both femoral heads, and the penile pulp, for the prostate
cancer patients.
The prescribed dose of PTV in case of breast cancer was 42.5 Gray,
with 16 fractions, and with dose rate 2.66 Gray per fraction. For the
prostate, the prescribed dose was 76 Gray, with 38 fractions, and with dose
rate 2 Gray per fraction.
The evaluation parameters used in case of breast cancer were: D2,
D50, D98,V95 and V107, in addition to HI, and CI. For organs at risk in
breast cancer patients: V16, V20 (Lung), Dmean, V25, V30 (Heart), In case
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121
of prostate cancer, the evaluation parameters used with either 7 or 5 fields
were: V95, V107, D2, D50, and D100. For the organs at risk in prostate
cancer patients, the evaluation parameters used were: V50, V60 (Rectum),
V65, V70, and D100 (Bladder), D100 (both Femoral heads), and Dmean
(Penile Pulp). The results of the study, can be summarized as follows:
* Breast cancer treatment data:
A. The planning target volume (PTV): In case of V95, 3DCRT was
better than IMRT, as judged by 95.9%, with 3DCRT, compared to 90.9% ,
in case of IMRT, respectively, with highly significant difference between
them at the level P ≤ 0.001, with each volume coverage. Also, according to
the over dose registration, 3DCRT is better where no records of over dose,
i.e., hot spots with respect to 4.1 recorded by the IMRT plan.
B. Organs at Risk:
Lungs and the hear are better coverage with the prescribed dose in case
of the breast cancer treatment planning with 3DCRT modality than the case
with the IMRT planning modality. This is clear with the lungs V16, V20
corresponds to 25.4, 19.3(3DCRT) vs 15.5, 13.5 (IMRT). Similarly, with
the heart, 3DCRT recorded less values than that of IMRT; 3.4 vs 4.69
(mean dose), 3.0 vs 8.0 ( V25), and 1.9 vs 5 ( V30), with significant
difference, at the level P≤ 0.05, except the case with V30, where the
difference was not significant at this level.
It can be concluded that, in case of breast cancer, the 3DCRT is preferred
than IMRT planning.
According to the homogeneity index obtained, the 3DCRT showed
slightly better value ,.i.e., 0.143 vs 0.253 in IMRT, with highly significant
difference between them, while in case of the conformity index, slightly
better value ,.i.e., 0.983 vs 0.944 in case of IMRT was obtained than that of
the 3DCRT, with significant difference between them.
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The homogeneity index was very close to each other in case of
3DCRT and IMRT with the 7 beam , i.e., with no significant difference
between them. Similarly, with the 5 beam technique, HI recorded 0.097 vs
0.094 in case of IMRT vs 3DCRT, with this value is better in case of 7
beam 3DCRT plan.
The conformity index, showed very close and acceptable values, .i.e.,
0.974 vs 0.959 in case of IMRT, and 3DCRT, with better value in case of 7
beam IMRT plan.
*Prostate cancer treatment data with 7 fields:
A. The planning target volume (PTV): The V95, V107 ,i.e., the
volume of PTV coverage by 95% and 107|% of the prescribed dose
calculated by the two techniques revealed that IMRT plan was better than
3DCRT planning treatment, as judged by 98.3%, 0.1 with IMRT, compared
94.9% , 0.0 in case of 3DCRT, respectively, with highly significant
difference between them at the level P ≤ 0.001.
Similarly, with D2, and D50, and D98, the partial volumes coverage
by 2%, 50% , and 98% of the prescribed dose recorded are higher in the
IMRT planning technique than that of the 3DCRT, i.e., 79.4 76.9, 72.4 vs
77.1 ,75.7, and 70.7, respectively, with highly significant difference
between them at the level P ≤ 0.001.
B. Organs at Risk:
The rectum received lower doses in the IMRT plan than that with
3DCRT, i.e.,27.5vs 46.8 (V50), and 18.1 vs 29.4 (V60), respectively, with
significant difference between them at the level P ≤ 0.05. Similarly with the
bladder which received lower doses with the IMRT than with 3DCRT, i.e.,
21.7 vs 24.5 (V65), 14.5 vs 16.0 (V70) with no significant difference
between them at the level P ≤0.05.
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Concerning with D100, relatively higher values were recorded with
IMRT than with 3DCRT, i.e., 10.7 vs 7.72 (Gy) in case of D100 bladder,
and 3.09 vs 1.38 (Gy) ( right femoral head), and 3.69 vs 1.79(Gy) ( left
femoral head),with no significant difference at the level P ≤ 0.05. However,
both values recorded by the two techniques, are acceptable by the RTOG.
The same situation is observed with Penile Pulp, which received relatively
higher mean dose with IMRT, than with 3DCRT, i.e., 29.5 vs 24.0 (Gy),
with no significant difference at the level P ≤ 0.05.
* Prostate cancer treatment data with 5fields:
A. The planning target volume (PTV): The V95, V107 calculated by
the two techniques revealed that IMRT plan was better than 3DCRT
planning treatment, as judged by 97.5%, 71.5% with IMRT, compared
95.2% , 70.6% in case of 3DCRT, respectively, with highly significant
difference between them at the level P ≤ 0.05, with each value is accepted
by the RTOG.
Similarly, with D2, and D50, and D98, the partial volumes coverage
by 2%, 50%, and 98% of the prescribed dose recorded are higher in the
IMRT planning technique than that of the 3DCRT,i.e., 79.1 and 76.6, and
71.5 vs 77.9 and 76.5, and 70.6, respectively, with no significant difference
between them at the level P ≤ 0.05, except with the D98, only.
B. Organs at Risk:
The rectum received lower doses in the IMRT plan than that with
3DCRT, i.e.,27.6 vs 27.8 (V50), and 15.9 vs 19.2 (V60), respectively, with
no significant difference between them at the level P ≤ 0.05. Similarly with
the bladder which received nearly the same doses with both techniques in
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case V65, and V70, respectively.
Concerning the D100, relatively higher values were recorded with
IMRT than with 3DCRT, i.e., 10.36 vs 7.23 in case of D100 bladder, and
1.81 vs 1.09 ( right femoral head), and 2.38 vs 1.62 (left femoral
head),with no significant difference at the level P ≤ 0.05. However, both
values recorded by the two techniques, are acceptable by the RTOG. The
same situation is observed with Penile Pulp, which received relatively
higher mean dose with IMRT, than with 3DCRT, i.e., 26.7 vs 23.7, with no
significant difference at the level P ≤0.05.
7 Beam Planning vs. 5 Beam Planning:
The Planning Target Volume
In comparing between IMRT and 3DCRT planning techniques with
respect to 5 beam and 7 beam procedures using the obtained data, we can
see that the two techniques record close levels of both V95, V107 i.e.,
(98.3, 0.1) vs (97.5, 0.0) for 7 beam and 5beam IMRT technique,
respectively, and (94.9, 0.0) vs (95.2, 0.0) for 7 beam and 5 beam 3DCRT
technique, respectively.
Organs at Risk:
In case of IMRT, the rectum receive very close doses in case of V50,
with slightly lower dose in case of 7 beam than 5 beam IMRT plan 27.5 vs
27.6), while in case of V60, lower dose value was received (18.1 vs 15.9 in
case of 5 beam vs 7 beam IMRT plan.
In case of 3DCRT, the rectum received lower V50, and V60 values,
i.e., 27.8, 19.2 vs 46.8, 29.4 in case of 5 beam and 7 beam 3DCRT.
The bladder, received lower doses with the 7 beam IMRT than 5 beam
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IMRT, i.e., (21.7, 14.5 vs 24.6, 16.0) for V65 , and V70 with nearly the
same values , in case of D100. These parameters, have very close values in
case of 3DCRT in the bladder.
In case of both femoral heads, and penile pulp, these organs receive
lower dose values with the 5 beam than 7 beam 3DCRT, i.e., 1.81, 2.38,
and 26.7 vs 3.09, 3.69, and 29.5 in case of right, left femoral head, and
penile pulp, respectively.
TCP and NTCP
The tumor control probability (TCP) and normal tissue complication
probability (NTCP) of radiotherapy plans were measured for 3D-CRT and
IMRT of prostate cancer. These two parameters are another tools of
comparisons between the two techniques.
The IMRT records slightly higher value of the TCP, i.e., 60.2% vs
58.4% for IMRT and 3DCRT, with acceptable values and with no
significant difference between them. This is in fair agreement with
Mesbahi A, et al., 2018, who reported that the TCP calculated using the
equivalent uniform dose (EUD) for prostate cancer revealed no
considerable improvement for IMRT plans relative to 3D-CRT plans.
According to the same authors, the TCPs calculated by Poisson model were
dependent on α/β, and higher TCP for IMRT relative to 3D-CRT was seen
for α/β higher than 5, which agrees with the present results, where the
average of α/β in this work was10.
The normal tissue complication probability (NTCP), in the present
work, revealed that the IMRT records better values in case of rectum and
bladder, which is also the case with the effective volume Veff which is
shifted to lower values as NTCP is lower. These data are also in fair
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agreement with that obtained by Mesbahi A, et al., 2018, who reported that
IMRT plans provided significantly lower NTCP for bladder ( 0.18 vs 1.21) ,
rectum(2.16 vs 2.52 and 24.44 vs 23.99) and femoral heads (32.92Gy vs
48.44) on average for both femoral heads ) using two mathematical models
;Lyman- Kutcher-Burman (LKB) and the equivalent uniform dose
(EUD) at the(p-value<0.05).
from the afore-said argument, it can be concluded that the IMRT and
3DCRT are accepted for the treatment of prostate cancer with 5 beam
technique. However, in comparing between the two techniques with 7
beams, the IMRT is preferable.