The Medical Radiation Engineering - Proton Treatments PART II
The Medical Radiation Engineering
Nuclear for peace...
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مدیر وبلاگ : مهدی
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چهارشنبه 10 تیر 1394 :: نویسنده : Amir

About prostate cancer

Prostate cancer is a condition which abnormal cells grow and form a malignancy on the prostate. Untreated prostate cancer can metastasize to other parts of the body, including the bones, lymph nodes and, in some cases, the rectum, bladder, and lower ureters.

The prostate gland, found only in men, is located near a man's urethra (just below the bladder and in front of the rectum) and serves many functions including producing seminal fluid (used to nourish and transport sperm), regulating and controlling urine flow by contracting and releasing muscle fibers and depends on adequate levels of testosterone to function properly.

While the prostate starts developing prior to birth, it begins to grow more rapidly during puberty in the presence of male hormones (most notably testosterone). Although the size of the prostate can vary by age, in young men it is usually about the size of a walnut. As men grow older, the size of their prostate can increase as well.

Numerous studies, including ones by the International Journal of Radiation Oncology and the International Society of Urology, biochemical failure rates (the return of a previously treated cancer) are the same for proton therapy as they are for conventional prostate cancer treatments such as brachytherapy and radical prostatectomy. This means that patients get the benefits of proton therapy without compromising their chance for a cure.

Advantages of proton therapy for prostate cancer

Proton therapy is a relatively newer cancer treatment, but it has already shown remarkable promise and advantages over conventional therapy – especially in the treatment of prostate cancer. Proton radiation therapy’s accuracy and the control it gives physicians in terms of adapting treatment make it a non-invasive and low-risk option for prostate cancer treatment.

What is proton therapy for prostate cancer?

Proton therapy for prostate cancer is a treatment option that involves using a focused ray of proton particles to destroy cancerous tissues. The treatment is capable of delivering precise, high doses of radiation to accurately target cancer cells without causing damage to healthy tissue surrounding the prostate.

Benefits of proton prostate cancer treatment

Proton therapy improves the quality of life for prostate cancer patients and survivors by offering a number of compelling benefits:

  • It is non-invasive and therefore painless
  • It is more accurate than other kinds of radiation
  • Full or higher doses of radiation can be used for treatment without damaging healthy tissues and organs
  • Treatment is provided in an outpatient setting
  • Proton radiation therapy does not require recovery time
  • The treatment has little to no impact on a patient’s energy level
  • Proton therapy poses minimal risk of impotency
  • The treatment has lower risk of side effects compared with conventional treatment.

What is breast cancer?

Breast cancer is a malignant tumor that originates from tissues of the breast. It is the second leading cause of cancer death, surpassed only by lung cancer.

The breast cancer tumor usually occurs in the lobules and ducts of the breast used in the production and delivery of breast milk. Breast cancer is the most common cancer among women aside from skin cancer. Although the disease is rare among males, men are also susceptible to breast cancer.

As with other cancers, the best possible outcomes for breast cancer come with early treatment.

Advantages of proton therapy for breast cancer

Although proton radiation treatment is relatively new, clinical trials for breast cancer have already shown excellent signs of disease control and minimal side effects compared with traditional forms of treatment. 

Proton therapy also offers a number of other compelling benefits:

  • Treatment is noninvasive and painless
  • Proton therapy is effective for treating early stage breast cancer
  • Treatment offers quicker recovery times with minimal side effects
  • Causes less cosmetic damage compared with the burn marks caused by regular radiation
  • It is more accurate and precise than other kinds of radiation
  • Treatment is provided in an outpatient setting
  • Proton radiation has little to no impact on patient energy level

Proton therapy treatment is an effective and desirable option to treat lung cancer.

  • Proton therapy concentrates a high dose in the tumor
  • Proton therapy is more accurate and precise than other kinds of radiation
  • Proton therapy spares healthy normal tissue and nearby organs
  • Proton therapy treatment is noninvasive and painless
  • Recovery times are quick and side effects are minimal
  • Treatment is provided in an outpatient setting

Proton treatment for pediatric conditions

Brain tumors in children

Tumors can develop in the brain in many different forms and severities. Proton treatment for brain tumors is highly individual. For selected adolescent patients, proton radiation therapy can minimize the potentially damaging effects of radiation on the normal developing brain and neighboring structures. For example, using protons to treat children with medulloblastoma minimizes the radiation dose to the middle and inner ear. It also reduces the risk of radiation damage to the pituitary gland and the optic nerves depending on the tumor type and location. Proton therapy offers the best available results achievable equal to using conventional radiation treatment for tumor control.

Orbital and ocular tumors in children

The orbit is the area surrounding the eye containing many important organs and structures. Each of these plays an independent role in eye function. The lacrimal gland is involved in lubricating the eye, as are the small glands located primarily in the upper eyelid. If these glands do not function properly, it can lead to dry-eye syndrome and ultimately cause a complete loss of the eye. To manage cataracts and prevent glaucoma in small children it is highly important to avoid unnecessary irradiation to the lens and the anterior chamber surrounding the eye.

Conventional radiation treatment might threaten eyesight; however, proton radiation therapy has successfully treated orbital rhabdomyosarcomas and retinoblastomas. Sparing a few additional millimeters of normal eye through proton therapy can affect the differences in eye function later in life. Some pediatric tumors treated include:

  • Sarcomas of the paranasal sinuses
  • Parameningeal rhabdomyosarcomas
  • Meningiomas

Sarcomas of the base of skull and spine in children

Once the safety of the treatment was firmly established in adults, physicians began using protons with increasing frequency in pediatric patients. Proton radiation therapy is successful for chordomas and chondrosarcomas of the base of skull and along the spine in adult patients as well as children. Currently, the experience includes a variety of:

  • Osteogenic sarcomas
  • Chondrogenic sarcomas (i.e., chordomas, chondrosarcomas)
  • Other soft tissue sarcomas (malignant fibrous, histiocytomas, synovial cell sarcoma, and others)
  • Principally benign but locally aggressive tumors (i.e., giant cell tumors, chondroblastomas, and osteoblastomas)

Tumors can be treated by proton radiation alone or in conjunction with chemotherapy. As is true of all consultations in the department of radiation medicine, conducting a careful review determining if additional surgery and tumor resection prior to proton radiation treatment would improve the chance of success.

Other conditions treated with proton radiation therapy

Base of skull

Acoustic neuromas

Acoustic neuromas are benign tumors that involve the eighth cranial nerve and they affect our hearing. With traditional radiosurgery, more than 50 percent of patients may experience a significant loss of hearing over time. This is because the large, single doses of radiosurgery can cause tissue damage to surrounding tissue.

At LLUMC’s Proton Treatment Center this problem can be avoided by using fractionation of radiation treatment. This process involves the division of the total radiation dose into smaller doses, which are delivered over a longer period so as to reduce the damage to healthy cells. This not only minimizes side effects, but also makes the treatment more effective. Consequently the proton radiation therapy can achieve a high rate of tumor control while minimizing the hearing loss associated with other forms of therapy.

Chordomas and chondrosarcomas

Chordomas and chondrosarcomas are tumors of the brain stem, spinal cord and central nervous system tissue. Proton radiation therapy has long been used to treat these tumors because it can deliver a high dose without damaging healthy brain or spinal cord tissues.


Read a patient story

These slow-growing tumors develop from the protective linings of the brain and spinal cord, which are called meninges. Meningiomas are almost always noncancerous (benign), but they can be difficult to remove because of their location. Proton radiation therapy’s precision makes it ideal for treating these tumors.

Proton radiation therapy is used for meningiomas to deliver a high dose of radiation in a few treatments. Long-term results show that proton therapy for benign meningiomas yields excellent results with minimal side effects.

Brain and spinal cord

Arteriovenous malformations (AVMs)

Arteriovenous malformations are defects of the circulatory system that are thought to arise during embryonic or fetal development or else soon after birth. AVMs are comprised of snarled tangles of arteries and veins. Proton radiation has been used successfully for many years to treat AMVs and success rates in the three years following treatment approach 80 to 85 percent for small AVMs.

Isolated brain metastases

Proton radiation therapy is used to relieve symptoms from isolated brain metastases. A high dose of radiation can be delivered in a few treatments, reducing symptoms and improving quality of life.

Pituitary adenomas

These tumors occur in the pituitary gland, which is sometimes called the “master” gland of the endocrine system because it controls the functions of the other endocrine glands. Currently, microsurgery is the treatment of choice in managing this disease. Success rates with surgery in microadenomas (tumors less than 1 cm in diameter) range from 70 to 90 percent, but are much lower for larger tumors.

Pituitary adenomas typically need additional treatment after surgery to cure or prevent recurrence. Radiation with photons and charged particles, such as protons or helium ions, has been used successfully in the past. More recently, pituitary adenomas have been treated with stereotactic radiotherapeutic approaches such as single-dose radiosurgery with the "gamma knife" or linear accelerator.

At LLUMC proton beams have been used for focal irradiation of pituitary adenomas since 1990. LLUMC has pursued high-precision fractionated radiation therapy – the division of radiation doses over a period of time -- as opposed to single-dose radiosurgery. This may be a more reasonable approach in cases where the target volume is larger than 1 cm and the tumor is adjacent to vital structures.


Uveal melanomas

Uveal melanomas, which are also called choroidal melanomas, are malignant tumors of the eye. Historically, these tumors have been treated by the complete removal of the eye. However, precise forms of radiation treatment such as proton beam therapy have been used to minimize the need for removal.

Protons have been used to treat uveal melanomas since the mid-1970s. Reports reveal control rates greater than 95 percent, with long-term survival consistent with survival rates for patients who have had their diseased eyes removed. Most proton patients have retained useful vision in their treated eyes. Results indicate that proton radiation is useful for medium and large tumors as well as smaller lesions.

Head and neck


Carcinoma of the nasopharynx is typically treated with radiation therapy alone. Local control rates for T3 lesions range from 60-85 percent. The corresponding rate is 45-70 percent for T4 tumors. Treatment-related complications can be severe because of the high doses received by critical structures surrounding the nasopharynx. These include:

  • Endocrine complications secondary to hypothalmic or pituitary dysfunction
  • Cranial nerve injuries
  • Trismus

One can increase the total dose to the primary tumor while shortening the overall treatment time by using the improved properties of proton radiation treatment. Proton treatment:

  • Increases local control of primary tumors
  • Reduces treatment-related side effects seen with conventional radiation
  • Is suitable for re-treatment of recurrent tumors


Patients treated for locally advanced oropharynx cancer usually receive combined surgery and postoperative photon radiation, or in some selected cases, radiation alone. Unfortunately, with either treatment approach a significantly high incidence of post-treatment morbidity has been reported. Severe treatment-related complications have been reported in up to 50 percent of long-term survivors. While greater doses of radiation are associated with improved levels of control, it also results in an increased complication rate. This is partly related to the large volume that is taken to a high dose using conventional radiation.

Proton treatment increases the total dose to the tumor while decreasing the dose to surrounding normal tissues.


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چهارشنبه 22 شهریور 1396 11:20
I always used to study paragraph in news papers but now as I am
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چهارشنبه 10 تیر 1394 08:28
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