Student cell lung cancer. They are small

                                                                   Student Name: Sonia khan                          Course: Access to sciencesUnit: Health physics (Assignment2)                          Health physicsAssignment2:2.

1 –Explainthe use of ionising radiation, ultrasound and lasers in medical treatment.5.1-Describeand evaluate the use of a given modern imaging techniques in a given treatment.IONISING RADIATION:Canceroccurs when cells in the body undergo a mutation that causes them to growrapidly and uncontrollably. Lung cancer forms when cancer cells invade anddestroy healthy cells in the lung tissues and air passages. It can take severalyears to develop. It may begin as pre-cancerous changes in the lungs thatneither cause symptoms nor show up on an X-ray.

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Eventuallycancer cells accumulate to form a tumour. As the tumour grows, it impedes theability of the lungs to function properly. Cancerous cells can break away fromthe original tumour, travel through the bloodstream, and form tumours in otherparts of the body. This process is called metastasis.         Althoughionising radiation can cause cancer, high doses can be directed at cancerouscells to kill them. This is called radiotherapy. About 40 per cent of peoplewith cancer undergo radiotherapy as part of their treatment.

It is administeredin two main ways:v From outside the body using x-rays orthe radiation from radioactive cobalt.v From inside the body by puttingradioactive materials into the tumour, or close to it.There aretwo main types of lung cancer. They are small cell and non-small cell. Thenames refer to how the cells appear to pathologists under a microscope. Eachtype and stage of lung cancer warrants unique treatment options.

Small Cell Lung Cancer (SCLC)Small celllung cancer accounts for 15 percent of all lung cancers. Small cell lung cancerstarts in neuroendocrine cells. These are the air tubes that lead to the lungs(the bronchi) and the cells in lung tissue. It grows very quickly. It produces largetumours that can travel through the blood and spread quickly throughout thebody. Small cell lung cancer mainly affects heavy or lifetime smokers.

There aretwo main types of small cell lung cancer. They are small cell carcinoma (oatcell cancer) and combined cell carcinoma. Oat cell cancer is the most common type ofsmall cell lung cancer. The cells resemble oats when examined under amicroscope.

Non-Small Cell LungCancer (NSCLC)Non-smallcell lung cancer makes up about 85 percent of all lung cancer cases in theUnited States. The cancer cells are larger, and the cancer is slower growingthan small cell lung cancer. NSCLC consists of three subtypes:•          Squamous cell carcinoma (or epidermoidcarcinoma) accounts for 25 to 30 percent of all lung cancer. It begins in thecells that line the air passages.

If not treated it may spread to the lymphnodes, bones, adrenal glands, liver, and brain. It’s the most common type oflung cancer in men and is heavily linked to smoking.•          Adenocarcinoma makes up about 40percent of all lung cancer. It forms in the mucus-producing (outer) part of thelungs. It develops slowly and is the most common type of lung cancer in womenand non-smokers.•          Large-cell (undifferentiated)carcinoma includes all non-small cell lung cancer that can’t be classified assquamous or adenocarcinoma (about 10 to 15 percent).

It sometimes forms nearthe surface, in the outer edges of the lungs, and grows rapidly. ( cancer symptoms do not usuallypresent themselves until the cancer is advanced.

This is why lung cancer oftengoes undetected in the early stages. Lung cancer symptoms include:•          Persistent cough•          coughing up blood•          Chest pain•          Recurring chest infections•          Voice hoarseness                                                 Figure 1: A Chest x-ray showing atumour in the lung Radiationtherapy is the delivery of focused high-energy x-rays (photons), gamma rays oratomic particles. It affects cells that are rapidly dividing, such as cancercells and much more than those that are not. Most cancers, including lungtumours, are made of cells that divide more rapidly than those in normal lungtissue, holding out the hope that the tumour can be eliminated without damagingsurrounding normal tissues. Radiotherapy acts by attacking the geneticmaterial—or DNA—within tumour cells, making it impossible for them to grow andcreate more cancer cells.

Normal body cells may also be damaged—though lessmarkedly—but they are able to repair themselves and function properly once again.The key strategy is to give daily doses of radiation large enough to kill ahigh percentage of the rapidly dividing cancer cells, while at the same timeminimizing damage to the more slowly dividing normal tissue cells in the samearea.Besidesattacking the tumour, radiotherapy can help to relieve some of the symptoms thetumour causes such as shortness of breath. When used as an initial treatmentinstead of surgery, radiotherapy may be given alone or combined withchemotherapy.

Today, many patients who have a small localized lung cancer, butwho are not candidates for surgery, are being treated with a radiationtreatment technique known as stereotactic body radiation therapy (SBRT).Patients who are poor candidates for surgery include the elderly, patients withchronic heart failure, and patients receiving a blood thinning drug that putsthem at risk of surgical bleeding. SBRT involves treatment with a multitude ofsmall, focused radiation beams tracking the lung tumour along with itsrespiratory movement, typically in three to five treatments. This treatmentdelivers very high doses of radiation therapy to the lung cancer in patientswhere surgery is not an option. SBRT is primarily used in the setting of earlystage, localized disease.

(Cancer research)Most often, radiation therapy isdelivered by the external beam technique, which aims a beam of x-rays directlyat the tumour. Treatment is given in a series of sessions, or fractions,usually over six to seven weeks for conventional treatments, and over one tofive treatments for patients that can be treated with SBRT. Three-dimensionalconformal radiation therapy or intensity-modulated radiation therapy (IMRT) arefairly new techniques based on a 3-D image of the tumour taken with CTscanning. This image serves as the target for a high-dose radiation beam thatcan change in shape and size to match the tumour. This method minimizesradiation exposure of nearby normal lung tissue.       Figure 2:Radiation therapy equipment used for lung cancer patients Typicalradiation therapy can be damaging to the body and cause unpleasant sideeffects, such as:v Temporary loss of appetite is apossibility.v Skin irritation is the rule after afew weeks of radiation therapy.

The affected area may be reddened, dry, tenderand itchy. This reaction can become quite severe during a long course oftreatment.v An inflammation of the lungs calledradiation pneumonitis may develop three to six months after radiotherapy isover.

It causes coughing and shortness of breath as well as fever but in mostcases calls for no specific treatment and gets better within two to four weeks. v Esophagitis, inflammation of the tubethat conveys food from the mouth to the stomach, is common after radiotherapyfor lung cancer and can be severe. The oesophagus is very sensitive toradiation, and worse damage occurs in patients who also receive chemotherapy.Esophagitis makes it difficult to swallow and some patients have lost 10percent or more of their body weight as a result.  LASERS:Psoriasis isa noncontagious skin condition that produces plaques of thickened, scalingskin. The dry flakes of skin scales are thought to result from the excessivelyrapid proliferation of skin cells triggered by inflammatory chemicals producedby specialized white blood cells called lymphocytes. Psoriasis commonly affectsthe skin of the elbows, knees, and scalp.

Some peoplehave such mild, limited psoriasis that they may not even suspect that they havethe disease. Others have very severe psoriasis that affects their entire bodysurface.Psoriasis isconsidered an incurable, long-term (chronic) skin condition. It has a variablecourse, periodically improving and worsening. It is not unusual for psoriasisto spontaneously clear for years and stay in remission. Many people note aworsening of their symptoms in the colder winter months.Severaltypes of psoriasis exist. These include:v Plaque psoriasis:  The most common form, plaque psoriasis causesdry, raised, red skin lesions (plaques) covered with silvery scales.

Theplaques itch or may be painful and can occur anywhere on your body, includingyour genitals and the soft tissue inside your mouth. You may have just a fewplaques or many.v Nail psoriasis: Psoriasis can affectfingernails and toenails, causing pitting, abnormal nail growth anddiscoloration. Psoriatic nails may become loose and separate from the nail bed(onycholysis). Severe cases may cause the nail to crumble.v Scalp psoriasis. Psoriasis on thescalp appears as red, itchy areas with silvery-white scales. The red or scalyareas often extend beyond the hairline.

You may notice flakes of dead skin inyour hair or on your shoulders, especially after scratching your scalp.v Guttate psoriasis: This primarilyaffects young adults and children. It’s usually triggered by a bacterialinfection such as strep throat. It’s marked by small, water-drop-shaped soreson your trunk, arms, legs and scalp. The sores are covered by a fine scale andaren’t as thick as typical plaques are.

You may have a single outbreak thatgoes away on its own, or you may have repeated episodes.v Inverse psoriasis: Mainly affectingthe skin in the armpits, in the groin, under the breasts and around thegenitals, inverse psoriasis causes smooth patches of red, inflamed skin. It’sworsened by friction and sweating. Fungal infections may trigger this type ofpsoriasis. (NHS)Psoriasis signs and symptoms can vary from person to personbut may include one or more of the following:v Red patches of skin covered withsilvery scalesv Small scaling spots (commonly seen inchildren)v Dry, cracked skin that may bleedv Itching, burning or sorenessv Thickened, pitted or ridged nailsv Swollen and stiff joint                                                 Figure3: Skin showing psoriasis  Today, thereis option for treating psoriasis: excimer lasers, which deliver ultravioletlight to localized areas of the skin.

Thistreatment uses intense, focused doses of laser light to help control areas ofmild to moderate psoriasis without harming healthy skin around them. Targetedlaser therapy is similar in effectiveness to traditional light therapy, but itworks in fewer sessions with stronger doses of light that can reach deeper intothe affected skin. The handheld laser wands are also good for reachingpsoriasis in hard-to-treat areas, such as the elbows, knees, palms of thehands, soles of the feet, and scalp.Laser treatmentsfor psoriasis use one of two types of lasers: a pulsed dye laser (PDL) or anexcimer laser.Pulsed dyelasers create a concentrated beam of yellow light. When the light hits theskin, it converts to heat.

The heat destroys the extra blood vessels in theskin that contribute to psoriasis, without harming nearby skin.                                                    Figure4: pulsed dye laser Excimerlasers aim a high intensity ultraviolet B (UVB) light dose of a very specificwavelength — 308 nanometres — directly at the psoriasis plaques. Because thelaser light never touches the surrounding skin, it reduces the risk of UVradiation exposure.

Excimer lasers are used to treat mild-to-moderatepsoriasis.With excimer laser therapy, patientsusually have two treatments lasting 15-30 minutes each week for three or moreweeks, with at least a 48-hour break between treatments. With pulsed dye lasertherapy, sessions go for 15-30 minutes every three weeks. (WEBMD)                                                      Figure 5: Excimer laser usedto treat psoriasis As well astreating this skin condition, it also has some side effects which include:  redness, skin discoloration, and sores,though these side effects are generally mild.ULTRASOUND:A fractureis a broken bone. It can range from a thin crack to a complete break. A bonecan fracture crosswise, lengthwise, in several places, or into many pieces.

Typically, a bone becomes fractured when it is impacted by more force orpressure than it can support.There aretwo types of fractures: open and closed.In an openfracture, the ends of the broken bone tear the skin. When the bone and skin areexposed, they are at risk of infection. This type of fracture is also called acompound fracture.In a closedfracture, the broken bone does not break the skin.

This type of fracture isalso called a simple fracture. But these fractures can be just as dangerous asopen fractures. Both types require medical attention.

(HEALTHLINE)Mostfractures are accompanied by intense pain when the injury occurs. Thisdiscomfort can become worse when the injured area is moved or touched. Somepeople may pass out from the initial pain of a fracture. Others mayfeel dizzy or chilled from shock.

Common symptoms that accompany a fracturealso include:v The sound of a snap or grinding whenthe injury occursv Swelling, redness, and bruising inthe injured areav An injured area that appears deformedor has a portion of the bone pushing through the skin.                                      Figure 6:Bones fractured in different ways Therapeutic ultrasound is a modalitythat has been used by physiotherapists since the 1940s. Ultrasound is appliedusing the head of an ultrasound probe that is placed in direct contact withyour skin via a transmission coupling gel.      Figure 7:Therapeutic ultrasound used to treat fractured bone The effectof ultrasound via an increase in local blood flow can be used to help reducelocal swelling and chronic inflammation and promote bone fracture healing.

Theultrasound waves are generated by a piezoelectric effect caused by thevibration of crystals within the head of the probe. The ultrasound waves thatpass through the skin cause a vibration of the local soft tissues. Thisvibration or cavitation can cause a deep heating locally though usually nosensation of heat will be felt by the patient. In situations where a heatingeffect is not desirable, the ultrasound can be pulsed rather than continuouslytransmitted. (PHYSICALTHERAPY) A typicalultrasound treatment will take from 3-5 minutes. In cases where scar tissuebreakdown is the goal, this treatment time can be much longer. During thetreatment the head of the ultrasound probe is kept in constant motion.

If keptin constant motion, the patient should feel no discomfort at all. Asultrasound is thought to affect the tissue repair process and so it is alsohighly possible that it may affect diseased tissue in an abnormal fashion. Inaddition the proposed increase in blood may also function in spreadingmalignancies around the body.

Therefore a number of contraindications should befollowed when using therapeutic ultrasound.Nuclearimaging uses low doses of radioactive substances linked to compounds used by thebody’s cells or compounds that attach to tumour cells. Using special detectionequipment, the radioactive substances can be traced in the body to see whereand when they concentrate.

Two major instruments of nuclear imaging used forcancer imaging are PET and SPECT scanners.The positronemission tomography (PET) scan creates computerized images of chemical changes,such as sugar metabolism, that take place in tissue. Typically, the patient isgiven an injection of a substance that consists of a combination of a sugar anda small amount of radioactively labelled sugar.

The radioactive sugar can helpin locating a tumour, because cancer cells take up or absorb sugar more avidlythan other tissues in the body.Afterreceiving the radioactive sugar, the patient lies still for about 60 minuteswhile the radioactively labelled sugar circulates throughout the body. If a tumouris present, the radioactive sugar will accumulate in the tumour. The patientthen lies on a table, which gradually moves through the PET scanner 6 to 7times during a 45-60-minute period.

The PET scanner is used to detect thedistribution of the sugar in the tumour and in the body. By the combinedmatching of a CT scan with PET images, there is an improved capacity todiscriminate normal from abnormal tissues. A computer translates thisinformation into the images that are interpreted by a radiologist.PET scansmay play a role in determining whether a mass is cancerous.

However, PET scansare more accurate in detecting larger and more aggressive tumours than they arein locating tumours that are smaller than 8 mm and/or less aggressive. They mayalso detect cancer when other imaging techniques show normal results. PET scansmay be helpful in evaluating and staging recurrent disease (cancer that hascome back). PET scans are beginning to be used to check if a treatment isworking – if a tumour cells are dying and thus using less sugar. Similar toPET, single photon emission computed tomography (SPECT) uses radioactivetracers and a scanner to record data that a computer constructs into two- orthree-dimensional images. A small amount of a radioactive drug is injected intoa vein and a scanner is used to make detailed images of areas inside the bodywhere the radioactive material is taken up by the cells. SPECT can giveinformation about blood flow to tissues and chemical reactions (metabolism) inthe body.

In thisprocedure, antibodies (proteins that recognize and stick to tumour cells) canbe linked to a radioactive substance. If a tumour is present, the antibodieswill stick to it. Then a SPECT scan can be done to detect the radioactivesubstance and reveal where the tumour is located.  


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